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GTP: A few Coolant problems

A

Alphaketo

New member
98 Grand Prix GTP

First problem: Coolant leak at what looks where the throttle body meets the supercharger housing. Now I just removed the throttle body to clean everything out. I didn't notice a leak before that. I assume that I need to change the gasket. However, should there be coolant in that area even with a gasket? I thought only air should be passing through there? If there is another leak behind the throttle body how do I tell where it's coming from and would I be able to change the gaskets of the supercharger or would I have to repair/replace?

Second problem: Just yesterday my car started overheating. It was also the day I removed the throttlebody and noticed that leak so it could be related. However I'm getting no heat and a cold radiator. Hot upper hose and relatively (for being next to unshielded headers) cold lower hose. From what I know these are classic signs of a blocked cooling system. So i just back flushed until i got clear water from both top and bottom of the radiator. The fact that there was water coming from both sides of the radiator leads me to believe there is nothing blocking it. I have a relatively new 160* Tstat also. So I go to refill it and I can only get in about half a gallon of coolant before the radiator starts overflowing. I drain it again, close the cap and pop the Tstat housing and try filling from there but get the same results, I can only get about half to 3/4 a gallon before it starts backing up on me. Unlike the leak I always noticed this problem. I just thought I was misjudging how much coolant I had but after flushing I would think I would be able to get atleast 2 gallons in there

Any ideas?
 


I have searched the forum for the answer but only saw answers that applied to NA grand prixs, and since the SC replaces the upper and lower IM I need an answer that is specific to the GTP
 
The TB has a coolant passage in it to make sure the tb plate does not freeze in the winter. Get a new gasket for that.

160º is WAY too cold, get a OEM 195º, you dont need to run anything cooler than that.

So you've pulled the lower rad hose and drain all the coolant from the rad and half the motor and can still only get 1 gallon in there?

I would just fill the LIM with coolant, bolt the thermo housing back on, fill the rad, run the car with the bleed screw open to vent any air, and keep adding coolant as needed. Bleed till alll the air is out and close up the cooling system and shut the car off, or take it for a drive
 
I am running a few mods and a 180 was suggested over a 195

I never pulled the lower rad hose I let it drain from the drain plug...should I have or would that suffice?
 


Alright, I appreciate the fast help. If autzone has it Ill do this tonight by candle light. If not ill try it early in the AM
 
One more question. Since this gasket is failing. Is the coolant leaking internally also? Am I getting coolant sucked into my blower? I only ask to know if it's OK to drive to the dealership in the morning or should I just let it sit till I replace the gasket. Last thing I want is a hydro-lock situation
 
It shouldnt go into the motor, but its posssible it could.

Just replace the gasket, fill with coolant and start her up and bleed it and all should be good.

Why's it going to the dealer?
 


I can't find the part listed at autozone and I don't have the time to wait for it to be delivered. So to the dealership i go.
 
Idk if anyone on here has experinced the issue but thermostats are cheap and can come bad. Not likely but possible. Also, did u just run water through the rad or through the motor too? Cuz u werent specific. Probably should've ran water through ur heater core hoses too
 
bps02gtp said:
Idk if anyone on here has experinced the issue but thermostats are cheap and can come bad. Not likely but possible. Also, did u just run water through the rad or through the motor too? Cuz u werent specific. Probably should've ran water through ur heater core hoses too
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I backflushed, which means i flushed through the inlet hose and it came out of both sides of the radiator.
As for the thermostat, I hadn't checked it, and I should check to see if it opens. But i figured since the top hose was hot there was coolant going through there
 
Dealership isn't likely to have it either. Call ahead.

As for the local places having it... they should be able to have it same or next day.
 
BillBoost37 said:
Dealership isn't likely to have it either. Call ahead.

As for the local places having it... they should be able to have it same or next day.
Click to expand...

No one had it so I went with closest GM place that would let me next day order over the phone. I should have it installed by tomorrow afternoon and I'll update on how it's running
 


Alright...pretty big f*** up





I repaired everything, and the car was running fine. I went to take my wife to work and it started overheating a bit. We were close and running a little late so I tried to tough it out...bad move. It got close to the red fairly quickly so I immediately pulled over and popped the hood. Apparently I hadn't fastened the inlet hose back tight enough and it blew. I had white smoke or steam coming from my dipstick and when i opened the oil fill tank there was sizzling/bubbling inside. And the coup de gras, bubbling coming from around where the fuel injection lines meet the crank case. So what do you think I have screwed up and how much of my money and time will I have to forfeit to fix it?
 
After it cooled down and i replaced the hose and put some more coolant in, i drove it and it stuttered badly at idle everytime i stopped. After a while it stopped. I still wasn't getting any hot air from the heater though.
 
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