I am in desperate need of help. I changed my thermostat a few weeks ago because I was not getting any heat through the vents inside my car. I did this once to my 92 camry, and it solved the problem.

After replacing the thermostat on my 98, I now have heat through the vent. However, the temp gauge consistently rises unless I turn my heat on full blast. I attempted to get all the air out but I thought that there was still some in, or possibly it needed a coolant flush. So, I took it to a mechanic my neighbor recommended because I had never flushed the system myself, and I was still unsure if I got all the air out.

Well, after $300+ and a new radiator (the mechanic said that's what it needed, but it didn't fix the problem) I am still having the same issue.

The fans do work when I turn on the A/C, but they are not coming on when my car idles and the temp starts to rise.

What could be causing this? Could it be a bad thermostat causing the fans not to kick on?

I am reluctant to take it back to the shop and tell them I'm still having the same problem. I do not trust them and I do not want to be scammed any further.

Any help would be greatly appreciated.

 

When does the temperature rise, hwy, idle, stop and go?

The fans have their own temperature switch, location depends on the engine model. If a 4 cylinder it is on the tank on the bottom of the radiator, fireside.

 

It willl rise mostly during idle. Going down the interstate it is fine. It seems to fluctuate a bit during stop and go, but once I get going fast again, it settles back to the mid-level point. I assume this happens because the air is hiting the radiator.

 

Did you use a OEM T-stat?

I had the same problem and the guy that installed the t-stat used after market, once I changed to OEM the problem was solved. You might also check to see if the fans are coming on at idle, the temp switch on the bottom of the radiator might not be working

 

Yes, check the switch at the bottom of the radiator.

Note: As a test, if the ign is on and you remove the electrical harness plug from the switch, the fans should turn on.

 

I unplugged the switch at the bottom of the radiator and the fans immediately came on. I am planning on installing a new fan switch this afternoon.

Could the aftermarket t-stat be the root cause of this? My dad is adamant on me getting a toyota t-stat from the dealer. If I have to replace it, I will... but I really hope that this nightmare will end with the fan switch.

 

It appears the fan system is OK, this leaves the switch. The switch grounds the fan electrical circuit which is why when the plug is disconnected the fans turn on.

You can test the switch in hot water, it should OPEN (no continuity) around 199F. But have continuity below 181F.

 

After replacing the switch, I am still having the same problem. I replaced the t-stat with an OEM this morning. Right now, I do not beleive the coolant is circulating because while the upper hose is hot, the bottom hose is cold. Please advise.

EDIT: I believe I bled the system of air thoroughly. After letting it run and "burping" the car by squeezing the upper and lower radiator hoses, I checked underneath the radiator cap and it was full to the top. I do not know what to do at this point. Any advice would be greatly appreciated.

 

Did you install the T-stat correctly. Spring side of T-stat facing engine (not radiator hose) and small hole or loose rivet on flange oriented upward?

Is the engine now overheating?

The engine will take a few minutes for the coolant to warm up to around 180F and start to circulate.

Typically burbing the hoses repeatedly for the full length of the hoses gets most of the air out, however if the T-stat has not yet opened up there will still be some air in the system.

How long did you leave the engine running before concluding the upper hose was hot and the lower was still cold?

 

Yes, the t-stat is in correctly. I did not know about the loose rivet being faced upward. Why should this matter? I will make sure I get that fixed tomorrow.

The engine would heat up normally, then after a short drive around the block, I would park it and let it idle and the temp would start to rise on the gauge.

I let the engine run for aprox. 15-20 minutes, including the drive around the block, which I assume would get the engine warmed up pretty well. The bottom hose was still cold.

What I plan to do tomorrow after church is remove the t-stat and unhook both radiator hoses and pump water through the system. See if there is a blockage. If there isn't, I plan on putting the old t-stat in and seeing what will happen.

Today I also put the aftermarket t-stat in boiling water and watched it open up. I doubt I will be able to take it back to the auto store since the quack mechanic I took it to drilled a hole in it.

Any other suggestions/advice would be greatly appreciated.