OK everyone and anyone who can help - my turbo GSR is giving me all hell when it comes to keeping cool for more than about 20 min of driving.

I decided I had a blown headgasket initially (MONTHS ago); replaced HG. When head was off I checked for cracks and warps and everything seemed fine and dandy. Before this I couldn't drive 5 minutes - after HG replaced it was as it is now... fine if I baby it, but if I try to pass or accelerate or anything silly like and drive for more than 20-25 min then it starts overheating.

I've tried:

new thermostats (2 or 3 - currently Jackson Racing 160F)

drilled 6 x 3/16" holes in thermostat

new radiator caps (3)

redline water wetter w/ all distilled and with 50% coolant

checked water pump - was replaced about 12000 miles ago and is in perfect condition

pressure tested radiator; no leaks

In any case when the car starts heating up, running the heater full blast keeps her cool even if I drive pretty hard.

I still kind of suspect a warped cyl head is allowing the HG to leak but perhaps less than before; the only check for this I've heard is to run the engine with the rad cap off. Before I replaced the HG I could see bubbles coming up the filler neck when I did this. Now I don't see the bubbles but the coolant DOES gradually overflow the filler neck if I idle it without the cap on.

One question I don't know the real answer to: does coolant ENTER the radiator through the UPPER hose or the lower hose?

When I had original headgasket problem I used a lot of "stop leak" aluminum powder type products in hopes that my coolant loss was through a leaky radiator (and at dad's advice) and now I'm wondering if this stuff has completely blocked flow thru the radiator in places and this back pressure is why the radiator overflows when the cap is off. Of course if the coolant flow is the opposite direction from what I'm thinking that wouldn't work. Right now I'm running some heavy-duty radiator flush in hopes that it might break up some of the stuff, just in case this is what's going on. Dunno if it will help but worth a shot.

Thanks for any help in advance.

 

i dont knwo exactly which way the water flows, but it does sound like one of your passages are maybe plugged up. makes me thnk that even more since you said the radiator over flows when the cap is off. keep trying to fluch it maybe that will help. i assume you fan is kicking on at the correct temp?

 

Once the coolant heats up, it will always expand and overflow. That much is normal. I'm thinking the radiator is clogged. keep your fingers crossed that its not the headgasket still.

 

You could try flushing the radiator and removing the middle part of the thermostat housing, that will allow it to cool down alot faster. Or just get a Fluiddyine radiator and that should solve problem. Our race car would over heat every time after one pass but since we put the Fluidyine radiator it keeps it at the right temp.


[Modified by 11sec.ALL MOTOR, 2:42 AM 10/31/2001]

 

Do the fans come on before it overheats? You shouldn't have put that stop leak **** in the coolant, someone has made shitloads of money selling that bullshit - does your dad use snake oil too? The coolant flows from the thermostat housing to the radiator. Get a funnel that fits into your radiator neck tightly and fill it with coolant/water mix. Start the car. Let it idle up to temperature (fans kick on). Once fully warmed- rev the engine to 2-3000 rpm. Watch for large quantities of bubbles. (the bubbles should become less and less as air is bled) If it starts to overheat- feel both hoses to see if they are both hot. Did you use new headbolts when you replaced the headgasket? It is possible that your radiator is plugged full of that "miracle" stop leak. Usually stop leak eats away at all of the coolant hoses- usually the upper hose gets it the worst.

 

Are your fans cut from having the turbo? That might hinder their ability. Could try getting some slim high-perf. fans... they might increase the airflow enough. Or try getting a Fluidyne/C&R radiator... all aluminum, larger than stock.

 

OK both my fans are working fine; i'm beginning to think more and more that stopleak is my real problem. I ran some heavy-duty coolant flush for around 4 hrs drive time; drained the coolant and rinsed her out about 4 times and got lots of yuck out of the system, but not nearly enough to have cleared a serious clog; refilled her with 50/50 coolant/water and some water wetter, and she still heats up after about 35 minutes to teh point that I have to drive with the heater on all the time the rest of the way to my destination.

I pressured up each cylinder at TDC to about 100 psi with the radiator full and the cap open; I assume that if the HG was leaking, the coolant level would rise or bubbles would escape through the radiator neck; this did not happen at all. There is also no sign of oil in coolant or coolant in oil so I'm assuming the head/block interface is not leaking.

I'm going to take it to a radiator shop again and see if they can find any sign of it being clogged from the stop-leak crap.

I'm considering the possiblity that maybe my "fixes" actually fixed the problem but that the chemicals have put a leak in my radiator (all hoses have been replaced in the last month) because after my 45 minute drive home last night (after filling, bleeding, refilling) I still had to add about 16 oz. water to the radiator to fill her up this morning. I know it didn't get hot enough to boil that much off, unless there was still a lot of air left in the coolant after my first bleeding attempt.

 

in our past experiance the stock rad is not sufficent to cool a turbo car.also the addition of the stop leak products could have further reduced the cooling of the rad.we use c&r racing radiator products here,good stuff.i would also do a leak down on each cyclinder with a leak down gauge,just to rule out a hg prob.hope this helps.

 

yea thats me joe,thanks for the kind words !! we try to provide good parts at good prices.just an update for you-we just finished up a b20/vtec for our race car.we are
still in the tuning stage for this engine.ran a 7.45 @ 94 mph last nite at the local
1/8th.have only made a couple of shake-down runs on the 1/4 with the best of
11.9 @ 114 mph.