Well, ive finally managed to diagnose the first problem ive had with my Teg so far. Sunday I noticed coolant leaking… we ruled out a radiator leak and today concluded that its the thermostat. (upper radiator hose very hot, coolant leaking from base of hose during hard or extended driving.) Anyway, I was wondering if there is a specific thermostat that needs to be purchased for Integras or if theyre a one size fits all part that I can pick up at Pep Boys. Also, any useful advice you guys have from your thermostat experiences I would really appreciate.
go to your local autoparts store, tell them you have a 91 integra and they will get you the right thermo. Diffent cars use different shape, sized, and temperature thermostats, so you want one for your teg.
It should cost $10-$15 and its super easy to install. But if its just a leak then i wouldn’t think its the thermostat, more of a hose, gasket or seal problem. If the car is overcooling, or overheating then you probably need a thermostat.
Lastly: BUY A MANUAL. Your manual will give you instructions on the thermostat install, as well as details on how to test a thermostat and what temperature thermo your car requires.
good luck
Yeah, I have they Haynes manual, its got all the info and troubleshooting info that led us to this conclusion. Im not thinking its the hose, because it only starts to trickle when it gets really hot in there, the thermostat isnt closing or something (which explains why too much coolant is running through there). I might try they test they have in the Haynes manual for the thermostat to be 100% sure. Thanks for your help.
OK, ive got the clamp off but the damned radiator hose wont budge, how do I get it off???
If it’s just to fix the leak,
replace the hose first and use
good aftermarket hose clamp.
The one that you have to turn
the screw to tighten.
If thermostat is bad, temp gauge
will tell you. Did you noticed
it take longer to warm up or
needle went past the middle ?
I havent driven it long enough to tell if it overheats or not, the temp gauge is right around the middle. It does take awhile to warm up it seems, i dont know what an appropriate time is, but it hovers around 1500rpm for a couple minutes on cold starts. I drove it hard a couple times around the block to test it and the hose was about 5x hotter than the other hoses with steam coming from where the hose connects with the thermo. Coolant was dripping from the hose only when it got hot (not when the car is first started though). I have a feeling it would have began to overheat if I drove it around a few more times, because there was already steam coming out. Im afraid ill blow the hose though which is why im trying to drive it as little as possible.
most likely its not your thermostat. I’d guess its either the end of the hose has a flaw, the hose clamp isn’t functioning properly, or the seal where the thermostat meets the block isn’t good anymore.
here is what you should do:
-pull off the hose, inspect it for any cracking (especially around where its leaking).
-while you’re there you might as well pull the thermostat out, clean off the mating surface and re install it with some gasket sealant or a new gasket (i can’t remember if it uses a gasket or just liquid sealant). While the thermo is out you might as well test it to make sure its working.
a properly functioning thermostat shouldn’t allow the needle to be in the middle. My thermo is new (so i know its good) and the needle just barely reaches the little design thing on the gauge. So, probably a bit more than 1/3 of the way up on the full range.
If the hose is good, and you reseal the thermostat and its still leaking then it could be the hose clamp.
Also, the coolant will leak more when its hot because there will be more pressure in the system.
I forgot to mention that the leaking occurs immediatley after the car is turned off, which is when i hear the depressurizing sound from where the hose and thermo meet. I dont think a new hose alone would solve the problem of why the area is overheating so much. The thermo has to be restricting something…
if the thermostat was restricting flow then your car would be overheating. You wouldn’t be able to drive it around for any longer than it takes to warm up before you notice that the temp gauge is reading high and is steadily rising. That would be if its stuck closed.
If its stuck open then its letting in plenty of coolant. The only problems you’d be having would be excess time to warm up, and over cooling when driving at night, at high speeds…
Ok now I got trouble… i checked the hose, cleaned out the buildup and took it for a 15 minute drive. This time the car DID overheat… i pulled into the driveway and there was lots of smoke coming from the radiator and coolant now on the radiator (appears it had sprayed out from the cap). Now i know its not the hose… im hoping that its JUST the thermo and not the radiator also. Seeing all that smoke freaked me out, took me back to the days of the '87 civic 
first of all its not smoke, its steam.
second, when you say cleaned out the buildup, what exactly are you talking about? did you remove just the hose? or did you remove the thermostat as well?
I took the hose off and there was like a buildup of a gravel-like substance where the hose meets the thermostat… i dont know what the hell it was or how it ended up there, maybe deposits from metal corrosion in the radiator or something. I didnt take the thermo out yet, the nuts are hard to get off. Anyway, the leak didnt come from there anymore after I did that but after about 10 minutes of driving the radiator was letting out a substantial amount of steam. The thermostat must be stuck closed.
Well, first off it sounds like originally you did have a problem with the connection at the end of the hose. That seal only leaked when the pressure had built up in your system. The stuff you cleaned off is from calcium and other mineral deposits in your tap water. This is why smart cautious people use reverse osmosis water in their coolent system.
Have you checked your coolent level?
Have you made sure that the fans are working?
Do you let your oil temp get to a reasonable level before you take it above 5000 rpm? (this has nothing to do with your current problem, but it will prolong engine life.)
Did you take out your thermostat and throw it in a cup of boiling water to check it before you buy a new one?
The seals dont leak until the car begins to overheat. I opened up the hood when this started to happen and saw the steam was clearly coming out from where the upper radiator hose meets the radiator. I also noticed that the fans were not on. As for the thermostat, the bottom bolt for the thermostat housing wont budge. Im using socket wrenches right now, do I need a tourqe wrench or something to get it off?
Well if you already made up your mind and went ahead to replace that thermostat…
Stubby wrench should help. I had no problem with
the bottom bolt but the one located on the right of the therm. housing was a b*tch.
Originally posted by LudeKiller91
The seals dont leak until the car begins to overheat. I opened up the hood when this started to happen and saw the steam was clearly coming out from where the upper radiator hose meets the radiator. I also noticed that the fans were not on. As for the thermostat, the bottom bolt for the thermostat housing wont budge. Im using socket wrenches right now, do I need a tourqe wrench or something to get it off?