Thread: Overheating with alot of pressure in cooling lines.

1997 Grand Prix SE. 2 days ago the temp started climbing after I replaced the air intake housing that holds the MAF sensor. I think its the throttle body. (I changed from a 98 Grand Prix GT for the new style MAF sensor). I checked the thermostat and it was stuck shut. That seems to fix it and it was running cool around 150 - 210. Replaced and today i started it and after about 2 mins of driving 45 MPH it blew out the thermostat seal and i could hear it releasing pressure for a few seconds after that. The temp at that point was over 210. Once it blew the seal it stayed around 150. The water pump is working and it was circulating through the entire system. Any ideas on what that could be?

I don't have a/c and ya i bleed out the air while it was idling and added coolant until it was full. old maf sensor was part# ending in 04 new one was ending in 05. car runs alot better with the new one and ran like crap with the old one.

my fans came on just over 150. i thought that meant it was ready.

so far i have found 2 versions of the maf sensor. yes i did modify it it for the transmission vacuum. i don't understand what your trying to say there blueguy. are you saying to put my old on back in? the one that was in this 98 gt has the large hole that went all the way into the housing (and that the same style my gtp has) and my old one had a small hole about 1.5 in deep and bottomed out in a cast housing. which i did replace new but didn't help.

On the other note about overheating, could it have been attrib to my my air intake changeover? also gonna change my seal again and wait longer to bleed the thermostat housing.

Blew TB gasket. Replaced and bleed out again. Running ok.