Going to replace the upper/lower hoses and thermostat before a trip on my 2003 Impala 3.8. The GM shop manual doesn't say anything about the pressure relief fitting on top of the thermostat housing. I plan on replacing the coolant, running the car for 10 minutes, let it idle and slowly crack the relief fitting on the thermostat housing and re-tighten.
Does this sound like a good plan?

Thanks,

John
1965 Malibu
Team #144

John,
Just my opinion but ... unless the car has a mess of miles on it, or the hoses look and feel bad, I would leave it alone. Twice in the past I have been "bitten" by trying to do maintenence right before a trip. Once was a new thermostat that decided to stick shut after about 200 miles, the other time a fuel filter change that ended up having some crud get into the carb after about 250 miles. Had fun rebuilding the Q-jet at a New Jersey Turnpike rest stop :( After those two experiences I will never do anything to a car other than maybe an oil change any sooner than a month before a trip.

If you decide to do it, the valve you are talking about is an air bleeder valve. Make sure you get the correct procedure and get all of the air out of the system.

Bill,
Thanks for the tips. I do have all the parts and will start it this week. Vacation is still a month away so will be able to test drive it before leaving. My son called and has a Haynes manual that describes the bleeding process. So much for spending $150 for GM manuals.
Have you ever re-used the GM spring clips with out any leaks? I'm tempted to try re-using the one on the driver's radiator side. It's a tight fit and probably have to remove the air cleaner box to use a regular clamp.
John

Sorry GM!! The bleeder screw IS mentioned on Page 6-470 of Vol. 2. Must be my old age! Fill slowly with bleeder screw open. Close bleeder, put radiator cap on and run for 10 minutes. Let sit and re-check fluid levels. Guess my $150 did pay off.
John

Bill,
Thanks for the tips. I do have all the parts and will start it this week. Vacation is still a month away so will be able to test drive it before leaving. My son called and has a Haynes manual that describes the bleeding process. So much for spending $150 for GM manuals.
Have you ever re-used the GM spring clips with out any leaks? I'm tempted to try re-using the one on the driver's radiator side. It's a tight fit and probably have to remove the air cleaner box to use a regular clamp.
John
As long as you do not distort the clamp..the constant tension hose clamps are reusable and reliable.