Just got back from doing some tuning and finally got it real close with street tuning. The last WOT run was in 3rd gear and went from about 70 to 120. Well when I let off of the throttle to coast back down, coolant sprayed up the passenger side of the car and the temp went up. I shut her down and pulled to the side of the road and popped the hood. All the hoses where intack and the coolant seemed to come from out of the overflow jug!! Well the first thought was a stuck thermostat, so we opened the bleeder valves and let off the pressure before opening the cap. Well the raditor was only about 1 quart low. So I pulled the thermostat out and it was open, but had no coolant. I added about 2.5 gallons of coolant and drove the car 80 miles home on the freeway with no issues. Temp was normal etc... Right before I get home, I went WOT through 2nd gear and stopped in my driveway. Only to find that I had blew out more coolant!!

Do you think I am lifting the heads at higher boost? I am making 13psi with a D1SC. The car idles and runs fine. No water in the oil or bubbles with the radiator cap off..

Also I noticed that I am pushing alot of oil out of the drivers valve cover. I will check to see if the gasket is bad or pinched, but should the valves covers see that much pressure?

 

how do you have your breather hose on the passenger side hooked up?

 

Both the breather hose on the passenger side and the PCV valve on the intake are connected to the suck side of the blower.

 

I had the very same phenomena occur to me. I'd driven the car for a few months and enjoying the boost frequently but never really holding into it for a really long stretch. Then I happened upon a liter sport bike at a stoplight. We took off on the green and I easily pulled away from him but had to feather the throttle in 3rd because it was starting to spin for a bit (M6 tranny). That was the longest continuous blast under boost. Next morning, when doing my normal pre-flight fluid checks, I saw for the first time that coolant was low. I added some then drove the car to work. Before I drove home after work, I checked the coolant. Phock! It was low again. I spent the next week or so checking and always finding the overflow bottle had increased and the radiator was low. First thing I did was to replace the radiator cap(stock one had been on there since bought new in '96). No change. I then went to Autozone and rented a pressure checker and checked the system. It held pressure just fine while it was not running/cold. I also took off the radiator cap(when cold), started the motor and rev'd the motor to see if any bubbles were showing while I viewed the open coolant. I assumed I harmed a head gasket so I bought some more FelPro 1074s and put them on. Didn't change a thing though (DOH!). Still pushing coolant into the overflow bottle. I decided I must have warped the head(s) so I ordered some Canfields. Meanwhile, I was in Autozone and saw a bottle of Prestone Super Sealer. Hmmm... Since I was waiting for the Canfields to arrive anyway, I decided "What's the harm? I'll give Prestone a try". Well I'll be damned... It stopped pushing the coolant! I now have a set of pristine Canfields awaiting to be installed someday. I don't need them right now. The car is keeping it's coolant and working fine! Btw, I've talked to more that a few FI guys that said they've used sealers like this to combat the same issues.

 

I would be really suprised you are having any issues with the heads and would not recommed using the radiator stop leak stuff. It sounds like your building pressure with your cooling sytem and it is being blown out the over flow tube. Im sure someone has fixed this and can help. If something is blocking the flow it will build pressure so high that it has no where to go but out that tube. Immediately after shutdown the engine enters heat soak. Its caused by the cooling system being inoperative while engine temps being still high. If it reaches boiling point it may push some out the overflow tube. As long as it doesn't happen often it is considered normal. Could be cracked head, block or manifold or faulty radiator cap. I would replace the cap since its so cheap and see if it helps. Maybe have the system pressure checked.

 

Here is the issue.. It will only force coolant out the overflow when I go WOT and hold it for more than a quick burst (5+seconds). It will spray out immediately. If I drive the car with little boost it does fine and doesn't spit out any coolant. There is no white smoke or other signs of leaks, just the overflow bottle.

 

Having too much coolant can cause this. Don't add anymore but make sure your not low and see if it continues. My old car would lose coolant and I would keep filling it. I stopped doing it and it hasn't leaked a drop since.

 

Kinda sounds like you are pushing boost into the coolant system?

Can you easily pull the blower belt and run it NA to see if this is still happening at high RPM? Just a thought.

-Scott.

 

For what it's worth, Advanced Induction ships a packet of official "GM Stop Leak" tablets with their finished product (to me anyway) which are designed to plug any small leaks/voids in the coolant system, even casting porosity if they occur.

I think it's great insurance to prevent a leak even if you have one. In reality it could be lifting the head slightly just enough to make a leak with all the combustion pressure.

If stop leak works, use it forever!

 

dookie..... send me that d1sc man!...lol...get an f1

 

Allready thought about an F1.. make me an offer and maybe I'll consider.
I hear the F1 is more for track use though?

 

ive drove a f1a car on the street. it was very streetable except for the whine.