PontiacBonnevilleClub.com

I have a 2002 Bonneville se that I picked up with multiple issues. I've repaired the other issues, but it overheats every now then. I've replaced the thermostat when I got it because it was overheating constantly. Fixed the two leaky elbows and drove it from my mechanic buddy's house to mine (about 60-70 miles) and it never had an issue. Now when I first start running her for a few minutes she gets hot, the reservoir is full, I can open the radiator cap and it'll fill and run fine, but it keeps happening. I'm not sure if I didn't vent it good enough to get the air out of the lines. I've done the block test, the heads are fine, no leaks, fans are blowing, no other issues. It just keeps flushing the coolant into the reservoir and doesn't vent it out fast enough or something. Could it be the aftermarket radiator cap? I'm lost and couldn't find any good info with the search function

Is the seal on the radiator cap good? If it is torn or damaged that could be causing your problem? Does the temp gauge go up and come back down while running? If not maybe the thermostat is stuck? hows the coolant? If it isn't nice and clean I would flush it out.

The seal looks ok, but I bought another cap. The coolant isn't bad looking, due to the previously leaky elbows the coolant is almost new but I'll probably flush it anyway. The temp will bump up a little then go back to normal 200ish, then it'll just go up until I vent the cap, after I vent the cap it stays at a steady 200. I'll mess with it some more after work and see if the cap makes a difference combined with bleeding it again

Changed the cap, bled the lines and she stays at a steady 200. Dude I bought her from put on an aftermarket cap that wasn't up to oem specs

Orvis wrote:Changed the cap, bled the lines and she stays at a steady 200. Dude I bought her from put on an aftermarket cap that wasn't up to oem specs

Don't you just love it? Maybe one of the reasons the car gave the previous owner so much trouble - didn't want to spent the extra dollar to make it run properly. Penny wise, pound foolish. - BC

I could tell dude was tired of messing with the car, I got it for $300, and it's nicer than my 91 which also had a slew of minor problems when I got it. It's a solid car again. Still trips me out that the cap made that much difference

Off topic - when are you going to clean-er up and post photos of the car (interior and exterior)? - BC

Soon. After I replace the water pump that went out. She ran great for a couple days, then the water pump bit the dust.