coolant leak

35

Asked by Sep 14, 2016 at 06:47 PM about the 2003 Pontiac Grand Prix GT

Question type: Maintenance & Repair

I have a small amount of coolant on the ground between the back of the engine and the firewall.  Pressure tested, no loss of pressure with the tester on all day.  Not intake manifold, just replaced the gaskets.  Not the elbows.  Not a freeze plug.  It leaks when the car is cold.  If it is warm or running, it doesn't leak.  The drip is coming between the oil pan and the transmission fluid pan.  I've checked hoses.  Car does not over heat, just noticed small amount on drive.  Maybe a few tablespoons.  

9 Answers

35

Sorry, forgot to provide info. 2003 Pontiac grand prix, 3.8L, not super charged

1 of 1 people found this helpful.
25,585

I would isolate the heater core and test that individually. See if the puddle is near the drain tube from the heater core box. You may have a tiny leak in the heater core that is dripping out the drain tube to the ground. When the engine is running and everything heats up the leak seals.

2 of 2 people found this helpful.
69,275

Check your belt tensioner. There's two plastic elbows that carry coolant from the engine, through the tensioner, to the heater core. They can be sneaky leakers. If that is the problem replace them with the better metal elbows. The two heater hose connectors on the belt tensioner are also suspect. Check them as well. HTH. -Jim

69,275

The knock sensors screw directly into the cooling system. Check them. HTH. -Jim

69,275

Did you do the lower intake? Or just the upper? Did you replace the plastic upper intake and not reuse the original one? They crack. HTH. - Jim

35

It's not the elbows, replace intake upper and lower gaskets. Gaskets are metal. Coolant collects on a bolt between the tranny and oil pan. Where are knock sensors located?

1 of 1 people found this helpful.
69,275

Knock sensors screw into the bottom of each head. One per head. You'll have to jack up the front of the car to see them from underneath. HTH. -Jim

35

Seems like the only way to see the leak is to drop the tranny. What are options? Freeze plug? Rear seal? Anything else?

1 of 1 people found this helpful.
69,275

There is a dye you can add to the coolant to trace leaks using an ultraviolet light. Freeze plug is a good suspect. These engines rarely, if ever, have head gasket issues. So I'd rule that out unless there's definite evidence of it. The block and heads are cast iron like in the old days so that's a big plus! The intake gaskets fail because you have plastic, aluminum, and cast iron all bolted together. Each has a different expansion and contraction rate when heated then cooled. Personally I wouldn't drop the transmission unless it's absolutely necessary to get to the freeze plugs. I've never replaced the freeze plugs so I really don't know (yet) what's involved there. Try the dye and see what you can find out from that. HTH. -Jim

Your Answer

Add photo

Related Questions

  • coolant leak 9 answers

    I have a small amount of coolant on the ground between the back of the engine and the firewall. Pressure tested, no loss of pressure with the tester on all day. Not intake manifold, just replaced th...

    2003 Pontiac Grand Prix GT

    -

    Maintenance & Repair

  • Coolant leak 4 answers

    I have a coolant leak that I can't find the where abouts, I've replaced the elbows, and reservoir/reservoir line.

    2001 Pontiac Grand Prix GTP

    -

    Maintenance & Repair

  • coolant leak 2 answers

    Drove 15 miles to work when I parked most of the coolant was on the ground and my car overheated. The coolant was under the lower radiator hose. Now looking for the leak the car retains fluid and keep...

    2005 Pontiac Grand Prix

    -

    Maintenance & Repair

  • Need help finding coolant leak on 1999 Pontiac Grand Prix 6 answers

    I've got a 1999 Pontiac Grand Prix 3.8 Supercharger which has had some odd coolant issue for a while. About two months ago I noticed the car seemed hot when running and especially when idling, but the...

    1999 Pontiac Grand Prix 4 Dr GTP Supercharged Sedan

    -

    Maintenance & Repair

  • Power steering leak 2 answers

    Leak in power steering. Put 12 ounces in this morning, 4 hours later, No power steering. Yes, there is noise also.

    2001 Pontiac Grand Prix GT Coupe

    -

    Maintenance & Repair

Grand Prix

Looking for a Used Grand Prix in your area?

CarGurus has 2,754 nationwide Grand Prix listings starting at $1,200.

ZIP:

Search Pontiac Grand Prix Questions

Pontiac Grand Prix Experts

#1 Js08016
Js08016
Reputation 4,370
#2 Tom Demyan
Tom Demyan
Reputation 2,970
#3 munron
munron
Reputation 2,350
View All

Related Models For Sale

Used Chevrolet Impala
574 Great Deals out of 34,604 listings starting at $695
Used Pontiac Bonneville
3 Great Deals out of 524 listings starting at $1,799
Used Chevrolet Monte Carlo
14 Great Deals out of 1,333 listings starting at $995
Used Pontiac Grand Am
1,069 listings starting at $1,599
Used Ford Mustang
731 Great Deals out of 42,661 listings starting at $1,300
Used Chevrolet Camaro
412 Great Deals out of 31,557 listings starting at $2,395
Used Pontiac GTO
11 Great Deals out of 467 listings starting at $5,995
Used Chevrolet Malibu
1,177 Great Deals out of 77,666 listings starting at $1,500
Used Pontiac Firebird
11 Great Deals out of 811 listings starting at $1,900
Used Honda Accord
971 Great Deals out of 62,362 listings starting at $999

Used Cars For Sale

2007 Pontiac Grand Prix GT For Sale
73 listings starting at $2,400
2006 Pontiac Grand Prix GT For Sale
7 Great Deals out of 73 listings starting at $1,800
2005 Pontiac Grand Prix GT For Sale
3 Great Deals out of 106 listings starting at $2,350

Content submitted by Users is not endorsed by CarGurus, does not express the opinions of CarGurus, and should not be considered reviewed, screened, or approved by CarGurus. Please refer to CarGurus Terms of Use.