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

3,230

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

3,230

Pressure test and go from there

3,230

Are the fans running?

3,230

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

3,230

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.

3,230

Fan relay or fuse blown.

3,230

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

3,230

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

3,230

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

So what's my next steps?

3,230

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 64 nationwide Grand Prix listings starting at $1,999.

Postal Code:

Pontiac Grand Prix Experts

  • #1
    Js08016
    Reputation
    4,470
  • #2
    Tom Demyan
    Reputation
    3,110
  • #3
    munron
    Reputation
    2,500
View All

Related Models For Sale

Used Chevrolet Impala
174 Great Deals out of 1,093 listings starting at $1,500
Used Pontiac G8
16 listings starting at $7,300
Used Dodge Charger
57 Great Deals out of 741 listings starting at $3,488
Used Chevrolet Monte Carlo
19 listings starting at $4,900
Used Ford Mustang
16 Great Deals out of 1,078 listings starting at $3,995
Used Pontiac G6
6 Great Deals out of 144 listings starting at $1,250
Used Pontiac GTO
4 listings starting at $13,900
Used Chevrolet Malibu
124 Great Deals out of 1,875 listings starting at $850
Used Chevrolet Camaro
926 listings starting at $13,495
Used Dodge Challenger
8 Great Deals out of 710 listings starting at $11,495
Used Chrysler 300
144 Great Deals out of 909 listings starting at $2,411
Used Jeep Grand Cherokee
154 Great Deals out of 3,611 listings starting at $3,500

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.