few thermostat questions

[skatanic28]

alrite, so pretty much everytime ive started my car in the past 3 or 4 days, after about 5 minutes of driving, then temp guage would go all the way to H, stay there for about 20 sec., then come right back down and everything would be normal. i searched around here and im pretty sure its just a sticking thermostat. so im gonna bleed the cooling system and replace the thermostat. where do you guys buy one? i went to autozones website and it said it was special order only. i cant see this being good for my car so i was kinda hoping i could do it today after work. so if anyone can point me in the right direction or give me a few tips i would appreciate it.

side note: i went to check out an s13 with my friend on sat....thought you guys would enjoy this.
90 coupe
135000 miles
missing front fascia
mangled hood
fair amount of rust
price.......3500 :rofl:
called to the guy to ask what he was thinkin, said a kid was comin with cash today.

[i-love-my-s14]

if your radiator cap i leaking that could be the problem. my car did the same thing, it would just randomly go all the way to hot then back down. i replace the thermostat and that did nothing, so i replaced the cap and it fixed it. so if it is leaking that could be the problem.

[skatanic28]

thanks for your input, do you remember how you went about picking up the thermostat? i havent really ever done anything with cooling systems before, but if the cap isnt holding the pressure wouldnt it be overheating pretty steadily and not come right back down after it hits H?

[i-love-my-s14]

no problem, umm i went to carquest or some auto parts store like that and they had a thermostat in stock. the temp would go up when i would hit the gas or when i was making the engine rev, because the pressure would go beyond what the cap could hold and then it would over heat. because my cap would hold the pressure sometimes and sometimes it wouldn't is why i think i would go up and down. im not saying it is your cap, but if it is leaking it is easier to replace the cap than the thermostat just to check.

[S14DB]

Your Radiator cap is not holding not your themostat. Get a 1.6Bar one.

[skatanic28]

oh alrite i get what your saying. cuz the water pump is belt driven so when the rpms increase more pressure is made and then its leaks. yeah ill definately check the cap too, and just run to a few stores lookin for the thermo. thanks for the help :)

[skatanic28]

well that was a pretty big pain in the ass to get to. everything seems to be fine now, i just ended up replacing the thermostat. i drove it around for about 15 minutes, then parked it and felt the lower rad hose, and it wasnt hot at all, but still a little warm. but no overheating at all, even with a half hour on the thruway today at 80. only thing that bothered me was when i drained the radiator, the coolant was dark green/brown. i really hope that its just really old or somethin, and not a head gasket leak. i checked the oil and it looked pretty good. i guess im gonna hafta try a compression test just to make sure. is it normal for the coolant to be dark like this?

[Dream240]

Well how many miles on your car? It sounds like rust in your coolant system. In most cases replacing the radiator is your best bet. Also replacing your upper and lower hoses at the same time.

Also flushing the coolant system professionally before you replace the radiator that way you get most of the rust out of your block.