Hey, i am new to the 86 community and i was wondering if anyone has any answers.

So i recently bought an 86 and i noticed that this one time it went to "HOT" when it was left out in the sun for 5mins while i pumped gas into the car. Then it dropped back to the middle so i thought it was nothing.

But yesterday, I wanted to see how fast the car is so i pressed the throttle hard and shifted to 3rd then slowed down. Few seconds later it went to HOT like instantly. and stayed there. I let it cooled down for 10 mins and it went back to the middle when i started the car again.

Another 10 minutes later right when i was about to be home the gauge went to HOT again. i'm not sure what's messed up. Is the engine actually overheating? Because it wasn't that hot when i popped the hood. IT was like warm.

The real temperature of the coolant in the engine cannot rise or fall instantly like
a switch being turned on and off. It can only rise and fall gradually as the engine
heats up or cools down. To go from normal to hot would take several minutes, and
cooling down would take much longer.

Here is the location for the gauge sensor...



It is the brown one with a single spade connector (clip not connected) next to the
greeen plug that the guy is holding. Check to see if the clip is firmly in place on
your sensor. If it is very loose and dirty, it could be momentarily losing contact with
the movement of the car. If need be, give it a clean and tighten up the clip with a
pair of pliers. Check to see that the wire is in good condition as well.

When the engine is cold, take the radiator cap off and make sure there is coolant
right up to the neck. Should be some (an inch or so) in the overflow tank as well.

Cheers... jondee86

I'll second jondee86 with checking the connector for proper connection and cleanliness and also making sure the you have coolant up to the neck of the radiator (like he said, check when cold). I have a leak somewhere in my 4ac cooling system and I get the same symptom if I neglect to add coolant on a semiannual basis. I can be driving on flat and straight and have no issue, then start going up a hill and temps go all the way to the H[ot] end of the gauge, or be on the freeway going around a corner and again the needle goes to the H. What's happening is the sensor for gauge temperature (the brown one in Jon's pic) stops seeing water temps and instead sees hot air temps. I've also had issues on my s13 where I don't bleed the cooling system sufficiently and an air pocket gets trapped right where the sensor for the gauge is, so it may also be worth it to purge the air out of the system completely. But easy stuff first though, make sure the connection is solid and your cooling system's full.

@jondee86
@purovida94

I checked the sensor and it looked pretty clean to me. What do you think? It's really hard to pull the plug out so i assume it has a solid connection.
Coolant is okay i think(checked when cold) what do you guys think?
me too!!! this happened when i was going up a small hill and it just instantly went to HOT.

How do i make it see water temp only then? instead of hot air temp.

Well so far everything seems okay. what do you guys suggest i do?












free upload pictures

Coolant looks clean, and you haven't mentioned any of the classic "engine overheating"
symptoms... like "need to keep topping up the coolant" or "steam and/or bubbles in
the overflow tank" or "radiator too hot to touch" etc. So I'm going to stay with a faulty
sensor or gauge diagnosis.

Time to break out the multimeter and check...
1. that the brass sensor body has continuity to ground (essentially zero resistance), and
2. remove the clip and check the resistance from the terminal to ground.

The FSM suggests that the resistance should be 226 Ohms +/-35 Ohms @ 122 degF and
26 Ohms +/- 2 Ohms @ 239 degF. Now 122 degF is a bit above warm, but 239 degF is
above boiling point, so don't try that at home Just make sure that when your engine
is cold the resistance is higher than 226 Ohms and when it is at operating tempertaure
the resistance is 60 or 70 Ohms or thereabouts.

Sine you are trying to trace what appears to be an intermittent fault, make sure you
give the gauge wire a bit of a shake while you have the meter connected. If possible,
keep the meter in your car so you can check the next time the gauge goes to HOT.

Cheers... jondee86

@jondee86

My friend told me I should add more to the coolant because it looks like it needs to be topped off. What do you think?

Sorry I am new to the ae86 community and also in the automotive world. :/ but isn't radiator always hot after driving?

I never used a multimeter before.
1. what do you mean by continuity to ground?
2. And what do you mean by check resistance from terminal to ground?

What's FSM?
So do you suggest I do the multimeter check when engine is cold and hot?
So I should drive the car around and if it goes to hot again check the sensor gauge with multimeter?

Sorry man I'm really new to this. If possible if you have time do you think you can make a quick 30 second video explaining? I know it's a lot to ask if you can't its cool.

Everyone has to start somewhere... we were all new to this stuff once

The FSM is the Factory Service Manual, and you can download it from here...
http://files.aeu86.org/manuals/4A-GEManual.pdf (big file 92MB)
For a start, I would suggest you download the manual and have a read. It will give
you a good overview of the engines mechanical and electrical systems... don't try
and understand it all at once, just be aware of where to look when you are trying
to sort out a problem.

If you didn't cover basic electrical circuit theory in class, then you can find any
number of youtube videos that give an introduction automotive 12 volt electrical
systems. You will also find videos and articles that show you how to use a multimeter
for testing electrical circuits and components. This link is one place to start....
Electrical Fault Finding 02 - CONTINUITY Testing

Get yourself a multimeter... doesn't have to be a flash one. I'm using a $35 digital
one, but I used a $15 analog one for years. You only need to be able to measure
DC voltage and resistance to sort most problems.

Cheers... jondee86

Swooki wrote:My friend told me I should add more to the coolant because it looks like
it needs to be topped off. What do you think?

Looks fine to me. When the radiator and expansion/overflow tank are working
properly, the radiator will always be full right up to the cap. Yours looks like it is.

Swooki wrote:Sorry I am new to the ae86 community and also in the automotive world.
but isn't radiator always hot after driving?

Yes, you are right, it will be hot. Bad choice of words on my part. However, there
is a difference between "normal" hot and "overheated" hot An overheated engine
will usually be blowing steam into the expansion tank when you stop the car and
pop the hood. It will smell hot and be throwing off so much heat that you won't want
to touch any part of it. That's when it pegs the gauge to HOT !!!

Cheers... jondee86

jondee86 wrote:Everyone has to start somewhere... we were all new to this stuff once

The FSM is the Factory Service Manual, and you can download it from here...
http://files.aeu86.org/manuals/4A-GEManual.pdf (big file 92MB)
For a start, I would suggest you download the manual and have a read. It will give
you a good overview of the engines mechanical and electrical systems... don't try
and understand it all at once, just be aware of where to look when you are trying
to sort out a problem.

If you didn't cover basic electrical circuit theory in class, then you can find any
number of youtube videos that give an introduction automotive 12 volt electrical
systems. You will also find videos and articles that show you how to use a multimeter
for testing electrical circuits and components. This link is one place to start....
Electrical Fault Finding 02 - CONTINUITY Testing

Get yourself a multimeter... doesn't have to be a flash one. I'm using a $35 digital
one, but I used a $15 analog one for years. You only need to be able to measure
DC voltage and resistance to sort most problems.

Cheers... jondee86

Oh okay cool. Thank you so much for the Manual.

I will look more into how to use a Multimeter so i can measure the sensor.
This is the Multimeter i bought from Amazon. Would this work?
https://www.amazon.com/gp/product/B01IS ... UTF8&psc=1

There are also some things i noticed today when i tried to bleed the air out of the Coolant System.
1. When i first started the car the temperature gauge was already at normal? ( i haven't started the car for 2 days) and 1 minute later it drops to Cold. (went back to normal after couple minutes or so)

2. The sensor seems kind of loose. Unless it's supposed to be like that what do you think and suggest i do about it?
https://www.youtube.com/watch?v=7Bv90qc ... e=youtu.be (Uploaded a video for you) [kind of shaky sorry about that]

3. The water pump has like pink coolant corrosion or whatever you call it on it. Does it mean there's a leak? and Radiator hose looks intact and fine.





image url

And regarding your SECOND post. I feel like it needs a little more coolant in the radiator. On the other hand, when i bled the system there was no air bubbles at all. The coolant was still like a rock. But it seems like it needs a little more topped off. Opinion?

The engine was just warm and was not blazing hot at all when i popped the hood a couple days ago!! GOOD SIGN! =) It was just warm. My strut bar was just warm also. Nothing like what you mentioned where it would be too hot to even get close to!

That multimeter will be fine.
- Measure DC volts using the 20 setting at 10 o'clock.
- Measure Ohms (resistance) starting on the 2000 setting at 6 o'clock and
moving to the 200 setting if the values you are measuring are small.
- Measure continuity with the setting next to 200 that has the two symbols
alongside. This should give you a "beep" when you touch the probes together.

If the gauge reading jumps up or down quickly, it looks more and more like
a faulty sensor, or more likely, a bad electrical (ground) connection between
the sensor body and the water neck casting. I see some signs of corrosion
around the sensor, and there could be a layer of corrosion in there preventing
a good contact between the sensor and the casting. This is the reason you
are going to test for electrical continuity between the sensor and ground
with the engine cold then hot. If you can test when the needle has pegged
to HOT, that would be even better.

In a car GROUND is any part of the engine or chassis that is connected by
wiring to the battery negative (aka ground) terminal. Because the sensor
has only one wire, it connects to ground thru the outer casing. Two wire
sensors don't need a connection to ground, and are not affected by corrosion
between the sensor and the surrounding housing.

The thermostat housing (the part the bottom radiator hose connects to) is
sealed to the back of the water pump with a paper gasket that is notorious
for leaking. Unless you can feel water under the housing when the engine
is cold, I would not worry about replacing it just now.

The AE86 cooling system has an expansion tank that is designed to accept
coolant pushed out of the radiator when the engine heats up, and then allow
it to be sucked back into the radiator when the engine cools down. This
means that when everthing is working properly, if you take the cap off a cold
radiator (or hot if you are feeling lucky) the rad will be full right up to the
underside of the cap. This assumes that the radiator was filled up to the
neck to begin with.

After that no topping up is normally required, but you do need to keep an
eye on the level in the expansion tank. Add coolant there if the cold engine
level goes under the minimum line. There will normally be a difference of
about 1/2" in the expansion tank level between a hot and a cold engine.

The connector on the sensor can move around a bit. So long as it has some
grip (not totally loose) it will be OK. You can check for continuity with your
multimeter just to be sure

Cheers... jondee86

jondee86 wrote:That multimeter will be fine.
- Measure DC volts using the 20 setting at 10 o'clock.
- Measure Ohms (resistance) starting on the 2000 setting at 6 o'clock and
moving to the 200 setting if the values you are measuring are small.
- Measure continuity with the setting next to 200 that has the two symbols
alongside. This should give you a "beep" when you touch the probes together.

If the gauge reading jumps up or down quickly, it looks more and more like
a faulty sensor, or more likely, a bad electrical (ground) connection between
the sensor body and the water neck casting. I see some signs of corrosion
around the sensor, and there could be a layer of corrosion in there preventing
a good contact between the sensor and the casting. This is the reason you
are going to test for electrical continuity between the sensor and ground
with the engine cold then hot. If you can test when the needle has pegged
to HOT, that would be even better.

In a car GROUND is any part of the engine or chassis that is connected by
wiring to the battery negative (aka ground) terminal. Because the sensor
has only one wire, it connects to ground thru the outer casing. Two wire
sensors don't need a connection to ground, and are not affected by corrosion
between the sensor and the surrounding housing.

The thermostat housing (the part the bottom radiator hose connects to) is
sealed to the back of the water pump with a paper gasket that is notorious
for leaking. Unless you can feel water under the housing when the engine
is cold, I would not worry about replacing it just now.

The AE86 cooling system has an expansion tank that is designed to accept
coolant pushed out of the radiator when the engine heats up, and then allow
it to be sucked back into the radiator when the engine cools down. This
means that when everthing is working properly, if you take the cap off a cold
radiator (or hot if you are feeling lucky) the rad will be full right up to the
underside of the cap. This assumes that the radiator was filled up to the
neck to begin with.

After that no topping up is normally required, but you do need to keep an
eye on the level in the expansion tank. Add coolant there if the cold engine
level goes under the minimum line. There will normally be a difference of
about 1/2" in the expansion tank level between a hot and a cold engine.

The connector on the sensor can move around a bit. So long as it has some
grip (not totally loose) it will be OK. You can check for continuity with your
multimeter just to be sure

Cheers... jondee86

Okay thank you so much!! will try the multimeter when it arrives =)

Is this normal for the gauge to be so out of place when the car is off? lol



Yeah. It jumped to normal when i started and went back to cold instantly after 1min.

Hm. Ground. So can it be like any metal part of the car? I remember learning something like that to put it on something as a ground when jump starting.. aha

Oh okay cool. I was worried about the water pump, but i will feel for water tomorrow when engine is cold ( will update you ).

[Where can i even get the water pump or thermostat? like AutoZone? would any thermostat or waterpump work?]

I guess the radiator wasn't filled to the neck lol when i opened the radiator cap, it looked kind of low like it needed more top off.
Should i fill it to 1st line or 2nd line?



Okay. So far the coolant in the expansion tank is always in the middle when cold.
I will check when it's in normal temp again.


Sick!! i was worried aha i thought it shouldnt have any play at all.

P.S. you're the only one that has helped me a lot. Thank you so much bro i appreciate it and Merry Christmas!

I will update you soon!!

The gauge is an electric one, so it does drop into a "parked" position when the
ignition is turned OFF. I'll have to check mine a bit later and see where it sits.
EDIT: Yeah... sits just under the C like in your pic.

GROUND will be any bare metal part that has an electrical path back to the battery
negative terminal. The shorter and more direct the path, the better. Corrosion
forming under ground wire connections is a common cause of electrical problems.

Replacement water pumps are readily available thru autoparts stores. You do need
to make sure you get the correct one for an AE86. The RWD ones are different from
the FWD (FX-16) versions. Thermostats come in all shapes and sizes to suit different
makes and models of cars. So you do need to get one that is correct foe an AE86.

Fill the radiator to the second line. Any higher than that and it will just make a
mess when you put the radiator cap back on

Cheers... jondee86

jondee86 wrote:The gauge is an electric one, so it does drop into a "parked" position when the
ignition is turned OFF. I'll have to check mine a bit later and see where it sits.
EDIT: Yeah... sits just under the C like in your pic.

GROUND will be any bare metal part that has an electrical path back to the battery
negative terminal. The shorter and more direct the path, the better. Corrosion
forming under ground wire connections is a common cause of electrical problems.

Replacement water pumps are readily available thru autoparts stores. You do need
to make sure you get the correct one for an AE86. The RWD ones are different from
the FWD (FX-16) versions. Thermostats come in all shapes and sizes to suit different
makes and models of cars. So you do need to get one that is correct foe an AE86.

Fill the radiator to the second line. Any higher than that and it will just make a
mess when you put the radiator cap back on

Cheers... jondee86

Oh okay. now i get it. sorry i don't understand how all these work lol. I guess there's nothing to worry about then.

How would i fix corrosion from wires?

Okay i haven't gotten a water pump yet. I was touching the bottom of it and it was dry. There's nothing leaking(only corrosion pink coolant stuff on top like the photo you saw)

But i did get a Thermostat today. I will switch it out shortly.


Oh okay! Thank you!!! I tried finding coolant at a autopart store but they only have universal ones? Would that work? Or is itbetter to get the OEM one from Toyota Dealership? 28.99 each(1 gallon) How many gallons does it hold? I might do a complete flush.

best, swooki

There is a saying... "If it ain't broke, don't fix it". So while I don't want to dampen
your enthusiasm for fixing up your car, I'd suggest that you don't really need to replace
a water pump unless it actually needs replacing. It's not like an oil filter that you just
unscrew the old one and screw a new one on. It's not a 5 minute job, and if you haven't
done one before, it can get a bit complicated.

Replacing the thermostat kind of fits in the same category. It's an easier job, but still
one that I wouldn't do until I knew the thermostat had crapped itself. That pink coolant
tends to make any dampness caused by gaskets weeping look more serious. My theory
is that if you check a few times under the housing or whatever gasket seems to be leaking,
and you can't pull your hand out with liquid on your fingers, then the "leak" is not worth
trying to fix. When it starts leaving a puddle on the floor like a dog with a urinary infection,
that is the time to replace the gasket

Better check that thermostat as well. I just put one in my car and it looked like this...



It might work, but you don't want to find out that it won't fit when you have all your
coolant in a bucket and the stores have closed. I'll see if I still have the packet somewhere
and get you the part number I ordered from Toyota.
EDIT: I bought this one... http://www.japanautopartsusa.com/thermo ... 03046.html
Fits a few different cars

If you are only topping up the coolant, you would be OK to use a some bottled drinking
water. The coolant will be mixed at least 50/50 with distilled water, so a little bit more
won't be a problem. Your coolant looks clear, so it's probably been replaced not so long
ago, and the pink stuff should be a "long-life" type of coolant.

Cheers... jondee86

jondee86 wrote:There is a saying... "If it ain't broke, don't fix it". So while I don't want to dampen
your enthusiasm for fixing up your car, I'd suggest that you don't really need to replace
a water pump unless it actually needs replacing. It's not like an oil filter that you just
unscrew the old one and screw a new one on. It's not a 5 minute job, and if you haven't
done one before, it can get a bit complicated.

Replacing the thermostat kind of fits in the same category. It's an easier job, but still
one that I wouldn't do until I knew the thermostat had crapped itself. That pink coolant
tends to make any dampness caused by gaskets weeping look more serious. My theory
is that if you check a few times under the housing or whatever gasket seems to be leaking,
and you can't pull your hand out with liquid on your fingers, then the "leak" is not worth
trying to fix. When it starts leaving a puddle on the floor like a dog with a urinary infection,
that is the time to replace the gasket

Better check that thermostat as well. I just put one in my car and it looked like this...



It might work, but you don't want to find out that it won't fit when you have all your
coolant in a bucket and the stores have closed. I'll see if I still have the packet somewhere
and get you the part number I ordered from Toyota.
EDIT: I bought this one... http://www.japanautopartsusa.com/thermo ... 03046.html
Fits a few different cars

If you are only topping up the coolant, you would be OK to use a some bottled drinking
water. The coolant will be mixed at least 50/50 with distilled water, so a little bit more
won't be a problem. Your coolant looks clear, so it's probably been replaced not so long
ago, and the pink stuff should be a "long-life" type of coolant.

Cheers... jondee86

Oh aha... I probably won't do the water pump then.
For the Thermostat i can't find videos on how to check if it's broken when the thermostat is connected to the hose hidden?
Oh okay aha. I didn't feel any liquid from the bottom of the water pump.

I was thinking of just switching the thermostat out anyway what if it's the problem?
As for the thermostat i checked autozone website and it said it fits my 1985 toyota corolla!! =)

For the list you sent me i don't see any hatchback gts? only coupes!

I found out that i need the red coolant instead of the pink one. I called toyota and they're like that 1980 and so on is red coolant and 2005-present is pink coolant. I think i'm go Autozone and pick up some 50/50 red coolant and add it to my car.
Eventually i'll do a full flush.

Swooki.

The thermostat is opened by the expansion of wax capsule that pushes a plunger
out against the spring when it gets hot. When it cools down the spring closes the
valve. Because heat has to transfer into the wax capsule to make it expand, even
if you drop a cold thermostat into boiling water, it still takes a minute or so for
the thermostst to open fully.

The obvious symptoms of a bad thermostst are (1) stuck open, when the engine
takes forever to get warm, the needle stays near the cold end of the gauge when
its cold out, and your heater does not blow hot air. Or (2) stuck closed, when the
engine overheats with the needle steadily moving over to the hot end of the gauge
as you drive. Eventually it will start to boil and you will see steam coming out from
around the edges of the hood

If you don't have any of these symptoms, then your thermostst is working OK.

Cheers... jondee86

jondee86 wrote:The thermostat is opened by the expansion of wax capsule that pushes a plunger
out against the spring when it gets hot. When it cools down the spring closes the
valve. Because heat has to transfer into the wax capsule to make it expand, even
if you drop a cold thermostat into boiling water, it still takes a minute or so for
the thermostst to open fully.

The obvious symptoms of a bad thermostst are (1) stuck open, when the engine
takes forever to get warm, the needle stays near the cold end of the gauge when
its cold out, and your heater does not blow hot air. Or (2) stuck closed, when the
engine overheats with the needle steadily moving over to the hot end of the gauge
as you drive. Eventually it will start to boil and you will see steam coming out from
around the edges of the hood

If you don't have any of these symptoms, then your thermostst is working OK.

Cheers... jondee86

Okay..(1)the engine doesn't take forever to warm.. warms up after like 5minutes+.. i have no heater so that's out.. (2) hmm no steam whatsoever. so i should return my thermostat then or just swap it out just incase?

Do you recommend a full coolant flush. I might do that.


Guess what?! I drove my AE86 out today at night i just wanted to see if it's still overheating. I started the car and sensor was already at normal temp already and dropped after 1 minute.
2nd- I drove around the block for 8 minutes then all of a sudden it jumped to HOT and i pulled over and then 10 seconds later it dropped to NORMAL operating temperature again. Then another 10 seconds later, it jumped to HOT.
So i shut off the car and popped the hood it was warm not blazing hot. I did notice this weird smell but i might be tripping also.

I gave it 10minutes again and it dropped to normal and drove home.

The sensor must be fooling me... or the gauge is broken?

I got my multimeter! doing research how to use.

Your pictures show that your car has an aftermarket aluminum radiator and Samco
hoses, so someone put a bit of effort into upgrading the cooling system. The coolant
looks clean which would suggest that it is not that old. If you bought the car from
somewhere close to where you live, then I would guess that it has the correct grade
of corrosion inhibitor/anti-freeze for your winter temperatures.

If you want to renew the coolant that is fine, but don't use any chemical flush. Just
run some fresh water thru it and then fill it with the recommended coolant. If it is
a concentrate, mix it with distilled or de-ionized water as per the label instructions.

The sensor must be fooling me... or the gauge is broken?

I'd bet money on it !! And you are going to use your new meter to figure out if it is
the sensor or the gauge

Cheers... jondee86

jondee86 wrote:Your pictures show that your car has an aftermarket aluminum radiator and Samco
hoses, so someone put a bit of effort into upgrading the cooling system. The coolant
looks clean which would suggest that it is not that old. If you bought the car from
somewhere close to where you live, then I would guess that it has the correct grade
of corrosion inhibitor/anti-freeze for your winter temperatures.

If you want to renew the coolant that is fine, but don't use any chemical flush. Just
run some fresh water thru it and then fill it with the recommended coolant. If it is
a concentrate, mix it with distilled or de-ionized water as per the label instructions.

The sensor must be fooling me... or the gauge is broken?

I'd bet money on it !! And you are going to use your new meter to figure out if it is
the sensor or the gauge

Cheers... jondee86

Yeah it has koyorad. came like that. i topped off the coolant with distilled water now it's on the line so it's good. Bought it from like 30-40 miles away from where i live.

UPDATE: so i got the voltmeter today but i still couldn't figure out how to fix it so my friend suggested that i buy a new coolant temp sensor at oreily's and i did for like 12 bucks. I switched the new one in and i drove around the block for like 2hours on and off. So far so good until 15minutes ago i was driving and it went to HOT instant again, i pulled over and popped the hood. It wasn't blazing hot at all it was warm so i closed it and went back inside the car. The gauge was at normal temp again.

Does that mean the sensor wasn't the problem? What is the problem..

How do i test the gauge if it's broken btw?

EDIT: I tested the continuity of the new sensor and it was at 0 sometimes go up by 1/2/3 and go back to 0 maybe im moving too much aha
and for the resistance with the wire i only got 68? I put the red probe on the wire and black on negative battery terminal and got 68. (I did drove it like 2hours ago though maybe that's why?)

Am i doing it correctly? what should i do now.

pictures of sensor and plug close up.

The wire connected to that female spade connector you are holding, looks like
it has been affected by corrosion and has broken strands. You need to clean that
up first. Cut the wire back by half an inch or whatever it takes to reach clean
copper wire, and then crimp on a new female spade connector. Any electrician or
half decent mechanic will do that for you in about 2 minutes for a couple of bucks.

Then see if you still have a problem.

Cheers... jondee86

jondee86 wrote:The wire connected to that female spade connector you are holding, looks like
it has been affected by corrosion and has broken strands. You need to clean that
up first. Cut the wire back by half an inch or whatever it takes to reach clean
copper wire, and then crimp on a new female spade connector. Any electrician or
half decent mechanic will do that for you in about 2 minutes for a couple of bucks.

Then see if you still have a problem.

Cheers... jondee86

Hey so i contacted local mechanics and electricians and most of them said no to me lol only one person said yes and he was like i don't do that kind of stuff we do diagnostics for 80 and use the 80 bucks for the parts. He's full of it.. zzzz

Can i do this at home? Go to a local hardware store and get a female spade connector and do it myself??
Is there a video recommended?


Cut here?


and then twist the wires together into the female spade and electric tape over it?

Lot of pirates around your way huh ?? What about a car audio or alarm installer ??
They are crimping terminals onto wires all day and are usually into cars. Just roll
up with the car when they are not flat out busy and ask for a favour... having a
couple of beers in one hand wouldn't be a bad idea

Sooner or later you are going to want to have a crimping tool and a few terminals
in your tool box. but I wouldn't go to that trouble right now. If that connector you
have in your hand still has half the strands connected it is not going to fall off in
the next day or two. And since all the evidence points to a poor connection in your
wiring, there is no reason to worry about the gauge jumping up and down.

Like, your car is running fine and not overheating, so poke around until you find
someone to replace the crimp (friend, friends father, sisters boyfriend, old man
who lives down the road who is always fixing stuff, anyone who doesn't want you
to bend over for a 2 minute job) and get it done. If the problem stays, you will be
getting into action with your meter

Cheers... jondee86

jondee86 wrote:Lot of pirates around your way huh ?? What about a car audio or alarm installer ??
They are crimping terminals onto wires all day and are usually into cars. Just roll
up with the car when they are not flat out busy and ask for a favour... having a
couple of beers in one hand wouldn't be a bad idea

Sooner or later you are going to want to have a crimping tool and a few terminals
in your tool box. but I wouldn't go to that trouble right now. If that connector you
have in your hand still has half the strands connected it is not going to fall off in
the next day or two. And since all the evidence points to a poor connection in your
wiring, there is no reason to worry about the gauge jumping up and down.

Like, your car is running fine and not overheating, so poke around until you find
someone to replace the crimp (friend, friends father, sisters boyfriend, old man
who lives down the road who is always fixing stuff, anyone who doesn't want you
to bend over for a 2 minute job) and get it done. If the problem stays, you will be
getting into action with your meter

Cheers... jondee86

Yeah man lol can't trust these mechanics..

I guess the car is fine aha. I just freak out although i know it's not overheating.
I'm going to top off the radiator with distilled water because when i took the sensor out a lil coolant came out.

I'm going to go to my local hardware store and get a female spade connector and find someone to help me i guess lmao buying the tool is too expensive for a simple job .

Yeah i get how to use the meter now but did i tell you that when i measured the resistance of the female spade connector i only got 68 resistance max? not even close to 226 like you said.

New Years assignment
EDIT: Read this first... https://www.carid.com/articles/digital- ... asics.html
Then do the tests like this...
1. Disconnect the terminal from the sensor.
2. Put one probe on the male spade terminal.
3. Put the other probe on the water neck close to the sensor.
4. Wriggle the probes to make sure they are getting a good contact with the metal.
5. Set meter to Ohms and read the resistance (should be something like 250 Ohms).
6. Move the probe that is on the spade terminal to the brass hexagon on the sensor.
7. Keep the other probe where it is on the housing.
8. Read the resistance (should be zero Ohms).
9. Repeat the procedure until you get the same reading each time.
10. Report back.

Cheers... jondee86

jondee86 wrote:New Years assignment
EDIT: Read this first... https://www.carid.com/articles/digital- ... asics.html
Then do the tests like this...
1. Disconnect the terminal from the sensor.
2. Put one probe on the male spade terminal.
3. Put the other probe on the water neck close to the sensor.
4. Wriggle the probes to make sure they are getting a good contact with the metal.
5. Set meter to Ohms and read the resistance (should be something like 250 Ohms).
6. Move the probe that is on the spade terminal to the brass hexagon on the sensor.
7. Keep the other probe where it is on the housing.
8. Read the resistance (should be zero Ohms).
9. Repeat the procedure until you get the same reading each time.
10. Report back.

Cheers... jondee86

Just finished reading the article. I have a better understanding but i did not see a resistance part.
This is what i did earlier.
1. Disconnected the female spade terminal from sensor.
2. Put red probe on female spade terminal and black one on water neck next to sensor.
3. Moved around the probe to ensure connection.
4. Set to Ohms i tried all settings and highest i got was 071. Not even close to 250ish. I notice the ohms would be 300+ then drop to 071 maybe i'm moving? I doubt it tho. (Engines cold)


Next i put red probe on the gold brass hexagon thing top on top of the sensor at the top of red circle
and kept black on housing and i got 0.

OK... zero is a good result for the sensor body to housing resistance. That means
the sensor has a good ground to the engine/chassis.

But you measured at the FEMALE spade when you should be measuring ay the MALE
spade to check the sensor resistance. Try again. Report back

Cheers... jondee86

Out of curiosity, I measured the resistance from the terminal to ground on
my water temp sensor, and it measured 1.214 kOhms (1214 Ohms) @ 12 deg C.
This is a bit more than I would have guessed, so it seems that the sensor has
a fairly steep rise in resistance as the temp goes down.

Gauge was working fine when I last drove the car, so I'd say the reading is legit

Cheers... jondee86

jondee86 wrote:OK... zero is a good result for the sensor body to housing resistance. That means
the sensor has a good ground to the engine/chassis.

But you measured at the FEMALE spade when you should be measuring ay the MALE
spade to check the sensor resistance. Try again. Report back

Cheers... jondee86

jondee86 wrote:Out of curiosity, I measured the resistance from the terminal to ground on
my water temp sensor, and it measured 1.214 kOhms (1214 Ohms) @ 12 deg C.
This is a bit more than I would have guessed, so it seems that the sensor has
a fairly steep rise in resistance as the temp goes down.

Gauge was working fine when I last drove the car, so I'd say the reading is legit
Cheers... jondee86

Oh LOL i was tripping out i thought you accidentally put male my bad ahaha
I will check again.
By the way i have two questions.
1) I was driving my car for 15minutes to see if it overheats and it didnt. So i touched my top radiator hose it was warm and the bottom was cold? Then i checked again in 5 minutes after driving. It turned warm but the top radiator hose is definitely hotter than the lower. Does that mean my thermostat needs replacing if the temperature is different? Shouldnt it be the same?

2) You never told me how to check the gauge. Or you did? Is it the male terminal? lol

I don't think that there is any easy way to test the gauge, so put that on your
"things to worry about later" list Do the easy stuff first.

The radiator's job is to get rid of the extra unwanted heat generated by the engine
while it is working. The harder it works, the more unwanted heat that needs to be
transferred from the coolant to the atmosphere. So, if you like, the radiator can be
described as a single pass water to air heat exchanger.

Heat transfer occurs when the coolant entering the radiator is hotter than the air
flowing thu the cooling fins... as the heat from the coolant is transferred to the air,
the coolant temperature drops. Since the hot coolant enters at the top of the radiator,
the collant leaving at the bottom of the radiator will be at a lower temperature, and
bottom hose will always be cooler than the top hose.

When the engine is idling the amount of unwanted heat is small, and easily removed
by the radiator, so the bottom hose will be barely warm. But when you have been
pushing the engine hard, there will be a lot of heat to remove, and the bottom hose
will get hot, but never as hot as the top one.

So your cooling system is working as it should

Cheers... jondee86

jondee86 wrote:I don't think that there is any easy way to test the gauge, so put that on your
"things to worry about later" list Do the easy stuff first.

The radiator's job is to get rid of the extra unwanted heat generated by the engine
while it is working. The harder it works, the more unwanted heat that needs to be
transferred from the coolant to the atmosphere. So, if you like, the radiator can be
described as a single pass water to air heat exchanger.

Heat transfer occurs when the coolant entering the radiator is hotter than the air
flowing thu the cooling fins... as the heat from the coolant is transferred to the air,
the coolant temperature drops. Since the hot coolant enters at the top of the radiator,
the collant leaving at the bottom of the radiator will be at a lower temperature, and
bottom hose will always be cooler than the top hose.

When the engine is idling the amount of unwanted heat is small, and easily removed
by the radiator, so the bottom hose will be barely warm. But when you have been
pushing the engine hard, there will be a lot of heat to remove, and the bottom hose
will get hot, but never as hot as the top one.

So your cooling system is working as it should

Cheers... jondee86

Okay aha so far it's been good i drove for 30 minutes straight over bumps and it's still normal temp.

OHHHHHH!! i got it!! sick!! people told me that i need to change it because it should be around same temperature. I believed them because i remember reading if the bottom one is cold and top is hot that means the thermostat is stuck opened. And mine was cold and turning warm so i assume it was starting to break ahahah

Now i get it. I'm relieved that it's normal for bottom hose to be at a lower temp than the top. Thanks for the insight brother!!

I did the resistance test of male terminal and i got = 1182 is that okay? EDIT: (Engine was cold, hasn't started in 24hours)