As part of my cooling upgrades, I went with the STi higher pressure radiator cap (in addition to my C&R radiator, Samco hoses, and Crucial 160deg thermostat). I kept having temp fluctuations that I attributed to not burping the system fully (cap went on at the same time as the tstat).

However, I've noticed a white streak down the inside of the fender area below the turbo. My first thought was the coolant return line, but the clamps are tight and there is no sign of coolant on the line itself (no white streaks). Getting under the car, I can see the same white streaks on the outside of the oil return line from the turbo. The streaks follow the line and then onto the front axle. There are a couple of drops of coolant on the axle as well. I've never seen any coolant below the car in a puddle or whatnot so I believe the leak is occuring while moving (and under boost/power). There has been a definite coolant smell after shutting the car off.

My question is where is the leak coming from? It seems to be turbo related? Is it possible the higher pressure is causing/identifiying a leak within the turbo itself? Or possibly at the coolant connections on the turbo? The rubber coolant lines themselves appear to be fine and there is no evidence of leaking. Anyone else had a similar experience or thoughts on what it might be?

I may just have to go to the trouble of pulling the turbo and looking underneath the thing.

BTW, it is a VF30.

edit: with the stock cap on the problem is gone or reduced to such a slight trickel that I don't notice it.

 

i've heard of this happening. you most likely split the end tanks of your radiator, which is not rated to the same pressure as the STi version. a search on this board or others may have prevented it.

in general, steer clear of uprated pressure caps. lower temp thermostats are fine.

good luck,
ken

 

Did you even bother to read the post?

1) The leak is somewhere near the turbo.

2) I have a C&R Radiator, not the stock one with the plastic tanks.

 

to answer your question then, no.

i don't have that problem, i haven't seen a problem like that, nor have i ever heard of anyone but you with anything remotely like it.

ken

 

 

nice.

for someone asking for help you're sure acting the dick.

 

Sounds like you solved your problem?

 

sounds kinda bad, is there temp variations?

 

Was your original response help? You didn't even bother to read the post before giving me a canned answer that had absolutely nothing to do with my situation. I tried to be extremely clear on what my particular problem was. Then when I pointed out that you had not read information that was in the very first sentence of my post, you left me a smart **** reply. All I am trying to do is get some answers on a problem.

 

I haven't really solved the root cause and I was hoping some of the other folks that have put GReddy or STi caps may have seen this problem and fixed it. I know there are other folks running a complete upgraded cooling path (tstat, radiator, and cap). It's just odd that I can't see the exact source of the leak.

 

Yep. The new tstat dropped my temps by 8 degrees or so, but they would start climbing at stoplights after a couple of days. At a stoplight I would see temps quickly rise to 210 degrees. I just assumed I hadn't burped the system completely, but after filling and burping twice now, and noticing the white streaks below the turbo, it appears to be a leak.

 

Have you reseated all the coolant lines? I know you said the clamps were tight.

Have you watched the area while someone revs it up? Must only leak under pressure. Good luck.

 

Mike, could it be leftover SeaFoam stuff? I remember that you had it leaking from an uppipe gasket when you did that, right? Otherwise, I have heard of other people getting leaks from the STi cap. I'm avoiding one for that reason myself.

 

Kevin,

It's definitely coolant. I think Dan is going to come by Saturday and rev it for me while I lay under there (if the weather holds out). I'll just put the stock cap back on, but I was really hoping to find the source of the problem since there is still a slight leak with the stocker.

MP,

All of the lines are tight. My suspicion is that it's the actual connection of the hard coolant line to the turbo, which is of course in a spot you can't easily see.

 

I finally got a chance to pull the coolant drain line off the turbo and inspect it. This is the rubber line that goes from the bottom fo the turbo to the engine block. It usually has a corregated metal hose over it for heat protection. That hose is why I never saw the leak. The rubber line inside of it has a small split in it. I almost didn't see it at first, but when you bend the rubber hose, it is obvious. Now I've got to find a candy cane shaped hose or piece something together in time for the next track day (dealer can't get this part in time). One mystery finally solved.