Engine Overheating?

Cklopp9 · 2015-05-05T16:42:19+00:00

HI.. I have a question concerning my 2001 Chevy Venture 3.4L. It is experiencning overheating problems , seems to be air in the cooling system. However everytime we go to start the van we need to let it heat up for about 20 minutes prior to driving it or it will overheat and sometimes it will overheat and all of a sudden drop to normal temperature. We have bled the air out and then it works fine for a few days and then starts to overheat again...could there still be air in the system?? Another problem it is having is that we were driving on the highway a little over a half tank of gas and all of a sudden the engine starting like puling when pushing the gas down and then we slowed down to stop and the engine turned off. When we went to try to turn it on it wouldnt turn on right away but after waiting for a few minutes it started. We ran a few feet and it started doin the same thing again. We were able to make it to our house by hardly pushing the gas down because everytime we pushed the gas it started the pulling again . COuld this be either the camshaft or crankshaft sensor??? Please help.