Where is the thermostat in a 1999 Pontiac Grand Prix 3.8L V6

Asked by May 22, 2014 at 02:47 PM about the 1999 Pontiac Grand Prix 2 Dr GTP Supercharged Coupe

Question type: Maintenance & Repair

I need to Locate the Thermostat on my 1999 Grand Prix, It is over heating suddenly & I was wondering if I could start with a possibly a cheaper fix than  taking it in for diagnostics & a new water pump, which is something I couldn't do myself.
Out of the blue on the 1st 80 degree day my car over heated and died after a 40-45 min. ride with an abnormal amount of idling due to wonderful construction. I have driven it to & from work twice since then, a 20-30 min. ride. It did not  die but it was quite over heated by the time I got home.

1 Answer

5,285

Assuming you have checked the coolant level and found it to be OK, the thermostat is a good thing to check in your diagnostic process. When they fail, they either let coolant flow without restriction (engine will be slow to warm up) or the stay shut and prevent coolant from getting to the radiator to be cooled down (your overheating symptom). I do not know the specifics of your car, but thermostats are typically mounted in a housing that is bolted to the front, top side of your engine block and has the hose to the radiator coming off of it. When the engine is cool, unbolt the housing and swap the radiator that sits in the cavity inside it. It is directional, so install it in the right direction. Ask the person at your parts store if you are unsure.

Your Answer

Pontiac Grand Prix Experts

  • #1
    Js08016
    Reputation
    4,420
  • #2
    Tom Demyan
    Reputation
    3,050
  • #3
    munron
    Reputation
    2,470
View All

Related Models For Sale

Used Chevrolet Impala
537 Great Deals out of 35,318 listings starting at $900
Used Pontiac Bonneville
504 listings starting at $3,699
Used Chevrolet Monte Carlo
3 Great Deals out of 1,279 listings starting at $1,488
Used Ford Mustang
591 Great Deals out of 36,392 listings starting at $1,200
Used Pontiac Grand Am
1,080 listings starting at $994
Used Chevrolet Camaro
452 Great Deals out of 30,864 listings starting at $2,495
Used Chevrolet Malibu
973 Great Deals out of 66,057 listings starting at $1,000
Used Pontiac Firebird
3 Great Deals out of 769 listings starting at $2,500
Used Nissan Maxima
267 Great Deals out of 22,949 listings starting at $1,499

Used Cars For Sale

2008 Pontiac Grand Prix For Sale
9 Great Deals out of 394 listings starting at $1,995
2007 Pontiac Grand Prix For Sale
14 Great Deals out of 390 listings starting at $1,449
2006 Pontiac Grand Prix For Sale
421 listings starting at $3,995
2005 Pontiac Grand Prix For Sale
5 Great Deals out of 340 listings starting at $1,450

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.