The check engine light can be any of several hundred problems, so my only advice there is to have the codes read and then cleared and see what comes back after driving.
As far as the overehating, if turning on the heater cooled it off, then you have a radiator restriction or flow problem. WIth the engine cool, make sure the system is absolutely full. Then operate the engine and feel of the radiator as the engine comes up to normal temp. If the heat does not transfer from the inlet to the outlet side efficiently, then it is a "flow" problem.
If you want to try to remedy it yourself, then a proper "flushing" will be the first step.
Many products are available to do this, and following the instructions carefully, you just may solve this problem yourself.
Wednesday, July 18th, 2007 AT 3:35 AM