This issue is on my brother's car. For some reason the temperature gauge shows the car is overheating but I checked coolant on the resevoir and there's no singns of overheating. He had this problem long ago but had stopped, I think they replaced the thermostat, but now it's back again, could it be a faulty sensor?

 

well what model is this on? i've heard people say time and time again that the 4th gens have funky temp gauges.

and have you made sure the thermostat is opening and also that the fan is kicking on?

 

i would think its a faulty guage....unless the thermostat went on it again which is possible

 

When the car is reading that it is overheating, check the bottom radiator hose to see if it is hot or cold.

If cold, your T-stat is NOT opening and that is where your overheating problem is.

If the hose is hot, then the T-stat is doing its job and your problem lies elsewhere.

Some other things to check:
-Radiator fan is working or running when the car is hot
-Coolant level is sufficient
-No air bubbles in the coolant system
-Radiator is not clogged up

If you have another gauge sender unit, it may be worth while to swap that out and see if it reads differently.

 

It's a 92 si 4ws, I'll check what you told me. Thanks

 

triple check the grounds.

The ground to the thermostat housing and the valve cover on the drivers side.

 

It could be overheating but not bad. My car had a bad radiator and I thought it was a bad reading because I would let it get hot (230 or higher) and didn't seem hot at all...finally i let it go until something happened and at about 260 degrees i smelled coolant.

Take it on the interstate to get some airflow to eliminate the fan issue

Feel the hoses

Look at the bottom of the radiator....does it look bad towards the bottom?

Any CELs?

Bipass the thermostat if needed...i ran a summer without one. It won't do any harm. Just put it back in if you want your car to heat up this winter

 

A bad ground can cause the guage to red hot even if it isnt.

 

I had the same problem. First I changed the radiator because mine was the original 1992 one and didn't look too good. That worked for a week then my gauge cluster started to overheat to the 3rd bar everytime the fan would come on. Changed the tstat and still did the same thing. Changed the ground on the valve cover and that fixed it. So check your grounds.

 

I'll tell my brother to check all that tomorrow, thanks to all of you!!

 

YES! Double check all of your grounds, transmission, cylinder head, battery, ECU, etc...

 

The lower radiator hose is kind of warm, does it have to be real hot?

 

After driving around, it should be just as hot as the upper radiator hose. If you're just letting it idle its not going to get very hot quickly. I'd suspect the thermostat is stuck closed. Is the radiator fan even kicking on? If not, its definitely the thermostat blocking coolant from reaching the ECT sensor.

 

Fan is fine, I'll have time to check it out tomorrow since I have a day off, thanks.

 

i had the same problem brought it to a mechanic and they couldnt even figure it out. i put a new thermastat in and still over heated. so one i day i just let it sit and idle with the hood up and i could hear a tiny little whistle, there was a slit in my heater core hose way in the back and right near the clamp. sooo maybe check all the hoses?

 

try this too, its a easy trick, but check everything. this is only for the easy fix so u can drive your car. run the car then turn your heater on. it cools down the engine. see if the temperature on the gauge goes down.

 

Apparently there was some bubbles on the system, It needed some antifreeze also, might be leaking somewhere, temperature gauge didn't go all the way up, thanks a lot for your help.

 

lol! no problem.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by bb_one &raquo;</TD></TR><TR><TD CLASS="quote">When the car is reading that it is overheating, check the bottom radiator hose to see if it is hot or cold.

If cold, your T-stat is NOT opening and that is where your overheating problem is.

If the hose is hot, then the T-stat is doing its job and your problem lies elsewhere.

Some other things to check:
-Radiator fan is working or running when the car is hot
-Coolant level is sufficient
-No air bubbles in the coolant system


-Radiator is not clogged up

If you have another gauge sender unit, it may be worth while to swap that out and see if it reads differently.</TD></TR></TABLE>


mine is doing this and i replaced the thermostat today.the system was bled properly. the lower hose is still cold after the top one is very hot. the car seems to still run the same but i think the coolant is not circulating properly. i am going to try looking at the coolant with the radiatior cap off and look for bubbles. if i can determine that the headgasket is not the problem is the only thing left is the water pump, right? i just hope the head is not warped

 

well I think I just found out that I have a headgasket problem White residue inside the tailpipe would mean burned coolant, right? Also did see slight bubbling at the radiator with the cap off.