2003 Pontiac Grand Prix OVERHEATING

Asked by Sep 27, 2017 at 09:47 PM about the Pontiac Grand Prix

Question type: Maintenance & Repair

I have a 03 Pontiac Grand Prix GT that I
bought from a guy a cpl years ago. Started
to have overheating problems....took it to a
shop they flushed my cooling system n told
me some idiot who owned the car b4 me
filled the radiator with Stopleak. So long
story short for 3 yrs I constantly was
flushing my cooling system to get all the
brown gunk outta my cooling system. So
about 1 1/2 yrs ago I replaced my radiator
water pump timing belt at same said shop.
Just recently my car started overheating
really bad no white smoke but smell of
burning coolant in the cab bogged down
accelerstion, heat coming through the floor
vents etc. So I replaced the head gaskets,
radiator cap,stretch bolts, replace coolant,
bleed air outta system & had machine shop
machine the heads and check for cracks
chips all came back good. All was well for a
cpl days n now it's overheating fairly quick
after cold start and leaking coolant....so I
need HELP PLEASE!!!!

16 Answers

4,420

Possibly small crevices in the engine that are supposed to funnel coolant could still be clogged with stop leak. Did you replace the thermostat? I did not see this on your list. Coolant temperature sensor...is this original? Have you pressure tested system to make sure it is holding pressure?

Yes replaced therm

Yes replaced thermistat the only thing I can think of any more is cracked water pump or clog in the system sum where

4,420

Pressure test and go from there

4,420

Are the fans running?

4,420

You may be right in that there might be something wrong with the water pump. Impeller not turning?

4,420

Was the thermostat installed correctly? Not only the correct way of flow but upside down will not let the system bleed on some models. Does yours have a small hole on the rim? If so this needs to be installed in the 12 o'clock position.

4,420

Fan relay or fuse blown.

4,420

Check engine light on for coolant temperature sensor circuit that might uncover wiring issue.

4,420

Is your leak a visible leak or using so you don't know where it is going?

Correct I'm not sure if the impellers not turning or if there's a crack in the water pump..no check engine light. Well small puddle but no visible leak while cars sitting idle

Yes fans are kicking on a about 1/2 temp

Yes therm installed correctly

4,420

That small leak is enough for it to overheat. It is not holding pressure with a leak.

So what's my next steps?

4,420

If you are not exactly sure where the leak is, I would pressure test so you can see the leak. (Might not leak until it is under pressure). Then fix it so it holds the right amount of pounds that your system is designed to hold. (Generally 13 - 18 lbs). Your cap will sometimes have this number. If not test at 13 lbs. if you do not see a leak and you are losing pressure, test the cap and if it passes, you have an internal leak. Generally head gasket.

Your Answer:

Grand Prix

Looking for a Used Grand Prix in your area?

CarGurus has 57 nationwide Grand Prix listings starting at $8,600.

Postal Code:

Pontiac Grand Prix Experts

  • #1
    Js08016
    Reputation
    4,820
  • #2
    munron
    Reputation
    3,040
  • #3
    Dorian Hendricks
    Reputation
    2,420
View All

Related Models For Sale

Used Chevrolet Impala
24 Great Deals out of 924 listings starting at $2,400
Used Pontiac G8
10 listings starting at $7,484
Used Dodge Charger
35 Great Deals out of 885 listings starting at $3,995
Used Chevrolet Monte Carlo
13 listings starting at $7,999
Used Pontiac G6
127 listings starting at $2,994
Used Pontiac Grand Am
36 listings
Used Pontiac GTO
4 listings
Used Ford Mustang
55 Great Deals out of 1,554 listings starting at $2,900
Used Chevrolet Malibu
36 Great Deals out of 1,790 listings starting at $2,995
Used Dodge Challenger
31 Great Deals out of 847 listings starting at $9,750
Used Chevrolet Camaro
20 Great Deals out of 1,009 listings starting at $10,500
Used Chrysler 300
37 Great Deals out of 1,075 listings starting at $4,500
Used Pontiac Firebird
19 listings starting at $19,995
Used Jeep Grand Cherokee
54 Great Deals out of 5,522 listings starting at $3,950

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. Content will be removed if CarGurus becomes aware that it violates our policies.