Pontiac Grand Prix Richard Petty Edition coolant problem

[Rixhardprix]

I know that Pontiac’s have a history of overheating but this seems a little odd. I have a 1992 Pontiac Grand Prix Richard Petty edition that has the 3.6 L V6 dual overhead cam and whenever it gets warm, it seems to leak coolant from someplace but only if it’s warm. I don’t know what is going on. My mom said that when she owned it, she got mad at some thing that went over the battery that had to do with the cooling system. If anyone can help and help me figure out what is going on I would be greatly appreciative. Thank you :-)

[JUSTA6]

Pic's would be helpful from the top and bottom directly under the leak.  You can cover your phone in saran wrap to make sure it doesn't get wet.  Only leaking when it warms up is usually a rubber hose connection/clamp.  But keep in mind rubber products only last so long and your car is 30yrs old.

[Last Indian]

1 hour ago, Rixhardprix said:

I know that Pontiac’s have a history of overheating but this seems a little odd. I have a 1992 Pontiac Grand Prix Richard Petty edition that has the 3.6 L V6 dual overhead cam and whenever it gets warm, it seems to leak coolant from someplace but only if it’s warm. I don’t know what is going on. My mom said that when she owned it, she got mad at some thing that went over the battery that had to do with the cooling system. If anyone can help and help me figure out what is going on I would be greatly appreciative. Thank you 🙂

I believe you mean 3.4L & the 3400 are notorious for intake coolant leaks. Very difficult to find most of the time as the engine is really stuffed in. Lots of times in the very cold weather if the car sits out they will go into a very high idle because they also will get a vacuum leak because the intake is actually warped. So until the engine equilibrate to temp it stay high. Often times it’s simpler to just redo the intake.

[Frosty]

Last Indian - point of clarification from your comments.

1. Are you suggesting just an intake gasket replacement? Or....

2. Does the intake need to be checked for warpage and may need to be machined / trued up?

I definitely support examining the hoses and consider replacing them and the hose clamps.

[Rixhardprix]

Thank you for all the responses! I checked for leaks yesterday by putting a piece of paper under the engine yesterday after letting it run for a while and no leaks were found. I’ll be sure to check all the hoses when I get a minute. Thank you everyone!

[Last Indian]

11 hours ago, Frosty said:

Last Indian - point of clarification from your comments.

1. Are you suggesting just an intake gasket replacement? Or....

2. Does the intake need to be checked for warpage and may need to be machined / trued up?

I definitely support examining the hoses and consider replacing them and the hose clamps.

Frosty, to be clear I never did this repair so I don’t know what the dealer did. My daughter owned a 91 Grand Prix 3.4 & her car suffered the vacuum leak! What a headache. Her car did the the high rpm on startup for about a month. Every time she took the car to the dealer, by the time she got there the issue had resolved. Finally I went over to her place two different weekends to try & figure it out. Second weekend I took some ether with me. Took about 5 minutes in zero temps to find. I could actually see the small gap in the intake once I found it. Finally got the dealer to keep it overnight outside, but the car was under warranty so I don’t know what they did. 
Also had two different friends that had 3.4 who had coolant leaks from the intake, but again while I found their leaks I didn’t fix them so I don’t know what the outcome was.

Sometimes I just assume that folks do the easy checks, hoses, fitting connections, radiator, etc. So I often don’t mention them, but of course those should be checked first.

Edited April 21, 2023 by Last Indian