How JustAnswer Works:
  • Ask an Expert
    Experts are full of valuable knowledge and are ready to help with any question. Credentials confirmed by a Fortune 500 verification firm.
  • Get a Professional Answer
    Via email, text message, or notification as you wait on our site. Ask follow up questions if you need to.
  • 100% Satisfaction Guarantee
    Rate the answer you receive.
Ask Anthony Your Own Question
Anthony, ASE Certified Technician
Category: Pontiac
Satisfied Customers: 11808
Experience:  ASE Master Automobile Technician with over 20 years exp. in this field.
Type Your Pontiac Question Here...
Anthony is online now
A new question is answered every 9 seconds

2004 Grand Prix: I just flushed..cooling system..temperature gauge

This answer was rated:

On my 2004 Grand Prix, I just flushed and filled my cooling system using the service manual procedures. I also replaced the thermostat. Now, the temperature gauge gets nearly to the 'danger zone' and that has never happened before. Anyone know what would cause that? Could it be the wrong thermostat? Or might I need another part also.

Hi and welcome to Just Answer!


How was the system before you flushed it?

Customer: replied 8 years ago.
The system was OK. I am meticulous about the maintenance and the vehicle has 226,000 miles on it. It was due for a cooling flush so I replaced the hoses, cleaned the reservoir, replaced the thermostat, radiator cap, etc. The old coolant had about 100,000 miles on it and the temp gauge never got above 3/4. Now, after being on for only 20 minutes or so, the gauge gets to the 'red zone'. So of course, now I'm leery of driving it until I know what's wrong.

Check over the procedure below. Was this what you did?



Customer: replied 8 years ago.
Yes, exept I also followed the 'flush' procedure where I filled it with clean drinkable water first then ran the engine for 20 minutes. Then I let it cool, drained it, and filled with the 50/50 dex-cool.
Ok, you let it sit and filled it all of the way up, right?
Customer: replied 8 years ago.
Yes, I let it sit then filled it up all the way (the best I could tell). I could only find one bleeder screw (above the thermostat) and filled it until coolant was coming out of that hole. Had the reservoir half full also. If it was not completely full, how could I tell?
How many times did you warm it up and try to add some coolant?
Customer: replied 8 years ago.
Just once. Was nervous about keeping the engine on - plus it was getting dark. Might I need to do this several times to get enough coolant in there?
Yes. Also if it refuses to circulate, you may want to do the thermostat again and fill the engine right up to the bottom of the thermostat housing through one of the heater hoses with a funnel before you put another one in.
Anthony and other Pontiac Specialists are ready to help you
Customer: replied 8 years ago.
Thank you, XXXXX XXXXX I will do. I appreciate the help. With tomorrow being Sunday, I just want to get as much info as necessary in case I need to get parts because I need the vehicle to be drivable by Monday.
Thank you also and you are quite welcome! If you need any help tomorrow, Ill be here just so you know.
Customer: replied 8 years ago.
Just for my own curiosity, the service manual talks about cooling system bleeder screws (plural). Is there another one I should be concerned about? Other sites talk about it being near the water pump but I could not find any such thing. Also, on the 2004 Grand Prix (3.8L non-supercharged engine), do you know which is the inlet heater hose (top or bottom)? Not very clear in the manual.
The heater hose wont matter which one you choose to fill.
Customer: replied 8 years ago.
Thanks. First thing this morning, I filled the coolant and ran the engine for 20 minutes. The temp. gauge did not get above half way. I will do this a couple of more times to make sure there is sufficient coolant in the system. Thanks for all of your help.
You are quite welcome and i am glad to hear you got it.