over heats

i have a 95 lumina 3.1 w/air i changed w/pump, now i think i need to change the stat. im having a hard time doing it, and wondered if i was doing it right.
help!!
thanks
bob h

A repair manual is a necessity to do anything that requires opening the cooling system on these cars. There is a specific coolant fill procedure that, if not followed, will allow air to remain trapped in the cooling system. This air can lead to rapid overheating and head gasket failure.

i agree, you need a repair manual but in short, you drain all the antifreeze, buy some of the high milage stuff, a new thermostat, pull your old one out, new one in, bolt everything back, idle engine and fill antifreeze until it starts to bubble out, cap it, and your done

get that thermostat changed out and get it filled as much as you can with the bleeders open and whatnot. see if it gets hot. if it doesnt great. if it does i know those 3.1s can trap air like you wouldnt believe. what i usually do is this. warm the car up at an idle until it reaches operating temp then hold the throtttle at about 1200-1300 rpm. when it starts to get hot rev it up to about 2200-2400 and let off till it comes back down to 1500ish and rev it back up to 2200-2400 and repeat several times. you should be surging the engine like youre getting ready for a badass takeoff, in park . thats how it should sound anyway. what youre doing is working the cooling system to try and purge the air since the high spots are hard to work the air out of. after you do this warm it up as high as it will go without overheating and shut it down and walk away. let it cool down for 30-45 mins and check the overflow. fill it back up tot he hot line and do it again. hope this helps. i know when i do anythign to the cooling system on those bastids 9/10 i have to do this to get the air out even after i opened the bleeders and whatnot.

Be careful, as it doesn't take long to overheat one of these motors when air gets trapped. If you don't know what you're doing, you may be better off taking it to a garage that does. A $7 part causing you to blow your engine isn't an economical way to DIY.

Great forum. I had the same issue with my '99 Lumina 3.1 yesterday. I changed the water pump, got new hoses, and a serpentine belt. Actually I had to go back and fourth to AutoZone b/c they gave me the wrong belt, anyway. Everything went great got all things complete and did a short road test and everything checked out fine.

My wife took it to work today (4 mi) ad she said it was overheating. After reading the forums I figured I would have the local shop do the thermostat and they would also bleed the coolant correctly. Well they told me to just bleed the coolant and that was it, I didn't get charged for a new stat.

Anyway thanks for posting previously. It made me think about the problems and get the right fix.