Overheat light coming on

[Maliki2]

So about a month ago I drive to a store and I get out, I come back out and start my car with the AC on lowest setting and the overheating light comes on. I immediately shut off the car and look at the manual. I turn on the heat full blast...its 90 out and open the windows...and the light goes off.

Fast forward to yesterday. Waiting in line with my kid at MCDs, with the low ac setting on again.....the overheat light comes on again. I pull over shut off the car and then turn it back on and the light goes out. No smoke was seen but this car has smelled bad for quite awhile now. When I go to work sometimes you can smell a burnt smell coming from the engine area, I have opened the hood and it has been really hot in there.

Not sure what is going on but this isn't the firs time I have had problems with the engine and I'm starting to wonder about the integrity of the engine at this point...any clues?!?! Thanks.

 

[acamacho104]

My first question might seem a little silly, but is there enough coolant? If it's low you might want to try filling it the rest of the way.

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[Maliki2]

My first question might seem a little silly, but is there enough coolant? If it's low you might want to try filling it the rest of the way.

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First thing I looked at and there is plenty. Been to dealership few times and nothing about it. Very random. And I'm very pissed and untrustworthy of this car. I'm starting to think its a lemon, eventually the engine will go. And they really don't care.

 

[acamacho104]

Seems strange, maybe the thermostat isn't functioning properly

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[Stew]

The next thing I would do is confirm the engine temp is high, easiest way is with an Ultragauge/Scangauge type of OBD II connected device.

 

[Blue hedgehog]

The next thing I would do is confirm the engine temp is high, easiest way is with an Ultragauge/Scangauge type of OBD II connected device.

And.... If the coolant temp. sensor is going bad and registering say 240* when its really at 120* the scan guage/ultragauge will show 240* confirming what I suggest a infrared thermometer.

 

[acamacho104]

But if the sensor is bad that would explain the light and therefore solve his problem

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[Blue hedgehog]

But if the sensor is bad that would explain the light and therefore solve his problem

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But using the possible bad sensor to tell you what the temp is does nothing for the diagnosis. Another thermometer that you know is accurate must be used. Using a ultragauge to read the sensor data gives the exact results as the light. If the light says its overheating because the sensor is telling the ECM its too hot, the ultra gauge will report what the sensor is telling the ECM.

 

[Stew]

And.... If the coolant temp. sensor is going bad and registering say 240* when its really at 120* the scan guage/ultragauge will show 240* confirming what I suggest a infrared thermometer.

You're right about that. I should have worded that better, I meant simply confirm what the coolant temperature is, not to try and determine whether or not the ECT sensor is bad. The owner manual does not say, at least that I saw, what the threshold is for the warning light to turn on.

Certainly a separate know good thermometer would be the best way to take readings and rule out the ECT sensor at the same time, but from the OP's first post I got the impression something like this was beyond the scope of their ability.

Edit: I suppose knowing what the temperature actually is probably doesn't matter in the end, the fact that the light is coming on at all indicates something isn't right. Best bet is take it in to be looked at.

 

[SuperFudd]

Is the radiator fan working properly?

 

[Maliki2]

Is the radiator fan working properly?

I tried everything I could do to get the fan to come on and it still hasn't moved at all.

 

[$ub$onic]

I tried everything I could do to get the fan to come on and it still hasn't moved at all.

Try swapping relays.

Fuse box under hood, bottom right, two grey relays, swap spots.

You can also pop the cap off a relay and manually trip it out to insure the fan it self is working.

 

[Maliki2]

Try swapping relays.

Fuse box under hood, bottom right, two grey relays, swap spots.

You can also pop the cap off a relay and manually trip it out to insure the fan it self is working.

Will give it a shot tomorrow. Engine has been running hot for a long time but Ive always been told there is nothing wrong. I have had that overheat light problem now....when its VERY hot outside...in Vermont 80-90+ is hot. When I'm idle it comes on. When I start moving it goes out.

 

[$ub$onic]

Will give it a shot tomorrow. Engine has been running hot for a long time but Ive always been told there is nothing wrong. I have had that overheat light problem now....when its VERY hot outside...in Vermont 80-90+ is hot. When I'm idle it comes on. When I start moving it goes out.

As sucky as it may sound. Kick on the heater. It will drop engine temp pretty quickly

 

[Maliki2]

Try swapping relays.

Fuse box under hood, bottom right, two grey relays, swap spots.

You can also pop the cap off a relay and manually trip it out to insure the fan it self is working.

I've started to take video of these problems to show the service people who think I'm nuts...

http://youtu.be/e8lyyJphmL4

 

[Maliki2]

As sucky as it may sound. Kick on the heater. It will drop engine temp pretty quickly

I did slap that on...had my 7 year old in the car...its around 90 out and had all the windows open...horrible...I was roasting from the inside out!

 

[$ub$onic]

I did slap that on...had my 7 year old in the car...its around 90 out and had all the windows open...horrible...I was roasting from the inside out!

I would get a ultra guage. I have had a "no fan" problem in my sonic since may ish.

No cel, just never kicks on. I am suspecting the temp sensor in the rad. I have a alarm set on my ug at 225 to assure I do not over heat it.

 

[mowcowbell]

You'll find the motor regularly hits 225F (at least that's with the 1.4L). That is by default to improve engine efficiency. My old Toyota never got above 205F.

 

[$ub$onic]

You'll find the motor regularly hits 225F (at least that's with the 1.4L). That is by default to improve engine efficiency. My old Toyota never got above 205F.

Stock my 1.8 never went about 220. Tuned was 205-208. So 225 for me was a perfect limit.

 

[Maliki2]

Try swapping relays.

Fuse box under hood, bottom right, two grey relays, swap spots.

You can also pop the cap off a relay and manually trip it out to insure the fan it self is working.

So I swapped relays and the fan (assuming the radiator) didn't move. How would I go about getting it to move or run. I let it run, swapped heat and ac and nothing it just sat there. Now that I think of it , I don't ever remember seeing it move or heard it ever.