More cooling woes

[THAWA]

I finally got the timing belt and wawa pump changed. I had hoped this would solve my overheating issues, but alas still has the problems. Here's what I've got so far. After it gets too hot, the resivoir fills up and coolant bursts out of it, I can't hear or see if because I'm driving but when I open the hood theres a fair amount of coolant around the cap, and there's plenty driping right under it. Could this be from the radiator cap being too old or something, allowing too much coolant to go into the resivoir? IT's been flushed/refilled 3 times in the past month and a half or so. When ever the engine is around 3k rpms it starts to cool down, this seems very odd to me. None of this mess started until the day I switched to 20w-50 oil (don't ask why i did it). I had no overheating problems before that day, but since then it's been nothing but hell. Could this be part of the problem? So far I've changed thermostat, radiator and water pump but nothing has changed anything. I'm begining to think it does have a blown headgasket (probably the worst thing to happen right now).

[vrg3]

If coolant comes out of the radiator cap when it gets warm, two things spring to my mind: air bubbles and/or a bad cap.

Air expands a lot more than coolant when it gets hot. So if you have air bubbles and the system is full, it'll likely be way overfull when warm.

The cap could also just be bad. It's good to replace them periodically anyway. The spring wears, reducing system pressurization, and the o-rings can develop leaks.

[HomeSlice]

yah get a cool sti one i got one on my leg----
the cap is suposed vent a lil i thought.

[JasonGrahn]

underneath the cap, you'll notice there is a spring. As the coolant gets hot, it expands, pushing on the spring. Depending on what PSI your spring is at, this will determine when you cap starts letting out excess fluid.

anyone care to comment on the dynamics of water under presser and the temperature this makes it boil at?

[spoore]

Hey I think we have the same problem. I have changed the timing belt and water pump. It has new hoses and a new radiator. It just keeps over heating though. When I bought it the radiator cap had no spring and the thermastat was non-existant. My overheating didn't start until I put a new thermastat in and a new radiator cap. Now the only way I can keep it from overheating is to run without a thermastat. I hope one of us figures out what the heck is wrong soon.

[THAWA]

hehe, i was going to hijack your thread spoore bnut decided against it. Anyway, the coolant doesnt come out of the radiator cap (least I don't think so), it just fills the resivoir and comes out of the resivoir cap. I don't doubt it's the rad cap, but why would it happen the day I changed my oil. I had always payed attention to the water temp when I was driving, it never went above a lil below half ever, but after i changed the oil it goes hella hot in under 5 mins of driving? Maybe I should switch back to a thinner oil. :\ I dunno, thanks for the suggestion though.

[vrg3]

If your system fails to pressurize enough, the coolant's boiling point may not be high enough to operate safely without boiling anywhere in the engine.

Watch out for the STi caps, though... They run at a higher pressure than the cap specified for your car, so they stress all the seals, gaskets, and hoses a little more than they're meant to be stressed.

THAWA - by "reservoir" you mean the overflow tank, then? Maybe the coolant is boiling in localized hot spots or something, even if the overall system temperature stays cool.

I don't know what an oil change would have to do with it. Is it possible that you accidentally did something else at the same time?

[THAWA]

yeah I couldnt think of the correct name for it, but i did mean the oberflow tank. I also don't know what oil change owuld do, but it just seemed a little too odd that it would be coinciedence, know what i mean.

I've been hearing some wierd noises though, while refilling/burping the coolant. I turned the engine off and hear three pretty loud clicks like something was moving or something. Then after I got home today I went back outside after a few mins and heard, "tick tick hisssssss, tick tick hisssssss, tick tick hisssssss". I couldn't get a good bearing on where it was coming from nor see it because it was too dark, but it sounded like from behind the engine on the passenger side. Too many wierd things :\

[ciper]

Air in the cooling sounds like the most likely cuplrit. How the air got in the system is the bigger question. A leaking head gasket would be my first guess.

[THAWA]

I noticed today when I stopped at work that something was leaking, I looked around and it appeared to be coming from the same spot, right above the control arm. Didn't have a chance to fully inspect it cause I was late, but do you think It could be one of the coolant lines(going to the heater core or soemthing) that has a crack in it or is loose or soemthing. It could explain a lot. I'm going to check it out tomorrow (no sun sucks) but just wanted to get an idea if there are even coolant lines running in that area or whatever.

[THAWA]

better yet does anyone have a diagram of the cooling/heating system? google, a search here and in josh's scans turned up nothing

Well the thing that was leaking is just a tube that sticks down from the firewall on the passanger side righ above the first cat. It didn't look or smell like coolant but more like water. Is that thing supposed to do that?

[petridish38]

if you're talking about what i think you're talking about, that is your drainage for your evaporator. When the AC is on, it is normal to see water dripping out of there. the "tick tick hiss" might have just been the water dripping onto the hot exhaust causing the metal to contract and the water to evaporate. (Just a theory)

I would get my coolant "sniffed" to check for exhaust gases in the coolant.