I'm having a weird overheating issues with my integra gsr, any help would be great! Three weeks ago, the car started to overheat after a top speed run... It didn't lose coolant, it would randomly start to get hot but would go down by it self (when fan kicked on?) so I changed the tstat to a brand new OEM honda one.. Didn't have issues for over three weeks, even autox the car last weekend also, but yesterday driving to the track after a hard 3rd gear pull, it started to act up the same way as before. If I were to put it in neutral and rev it, the temp gauge would go right back down.

The car doesn't loose any coolant, there's no smoke, but the top radiator hose is hotter than the lower radiator hose. I hard wired the fan to see if it was the problem, car hasn't overheated yet ever since the time on the highway. Could it be possible that the brand new tstat is faulty? Could it also be a head gasket problem? Or could it be the fan switch?


Thanks!

 

its not ur tstat because it will either be stuck open, stuck close, or operating the way it's suppose to
if u dont smell coolant thru the vents, see no coolant leaks at all, and are'nt experiencing smoke, then u could eliminate the head gasket
which leaves u one thing...your fan.
just run back all these test to assure what ur problem is before u buy any more OEM parts g/l

 

^ Thanks a lot. I think my brand new oem thermostat is stuck closed because the top radiator hose will get hot while the bottom is cold. Even when I jumped the fans to come on, the bottom hose will be still be cold which leads me to believe the tstat is bad. Has anyone heard of a new OEM going bad?

 

not the t-stat. a hot upper rad hose is indication that the t-stat is opening, allowing hot coolant from the engine to enter the radiator. the lower rad hose should be cooler than the upper, as it has just passed through the radiator, but not cold. if it is, you may have blockage in your radiator.

first thing i'd probably do, because it's the easiest, is determine that the fan is kicking on when it should be. start the car up and let it idle. if the fan doesn't come on before it starts to overheat, you've got a problem with the fan motor, relay or the switch. jump the fan directly with 12v power and ground. if it doesn't come on, the problem is the motor. if it does, jump the relay with 12v power and ground. if it doesn't come on, problem is the relay or wiring between it and the fan. if it does, jump the switch connector with 12v power and ground. if it doesn't come on, problem is the switch, or wiring between it and the relay

if the fan kicks on, make sure that the rad cap is performing correctly. it should allow coolant into the reservoir at higher temps, and then allow it to be pulled back into the rad when cooler temps are reached. if the rad cap is not placing pressure on the system, the car will overheat.

you can check for blockage in the rad by draining the coolant (save it if it's relatively new). pull the upper and lower rad hose. run water through the upper rad hose inlet with a garden hose. it should come out the lower outlet at a steady stream, pretty much the same speed as it is coming in

 

I'm guessing it's a bad fan switch. Cheap to replace. Try it.

 

test the theory first. always

 

also did you bleed the cooling system after you replaced the thermostat

http://techauto.awardspace.com/overheating.html

 

Thanks, yes I tested the theory you posted and the fans do come on when I jumped the switch so looks like I'm going to replace the fan switch.. I will also replace the radiator cap and flush the coolant system. The lower radiator hose is a lot colder than the upper hose, but I will check the blockage of the radiator tomorrow.

 

so the fans didn't come on without being jumped at the switch connector? just wanna be clear here

 

Yes it will not come on unless it is jumped.

 

I have had this happen and it was air trapped in the cooling system not allowing the thermostat to operate proper!
Try a thorough bleeding of the cooing system.
Good luck

 

I agree replace switch then wouldn't hurt to make sure coolent is bleed free from any air in the system.

 

I would also replace the switch and to the bleed. I agree for the most part it's a fan issue.

 

Thanks guy, I changed the switch and it wasn't it. So I exchange the relay with another one I had, it was the relay that was the culprit! I re-bleed the system and replaced a new radiator cap anyways.