hello, I just purchased a 99 grand prix SE about 2 months ago, has a 3.1, 240,000 miles on it. Seems to run great but it got down to -20 degrees about two weeks ago and the car started to overheat driving to work, so i pulled over, shut it off, waited 15 mins and restarted and it was cool and stayed cool. ran fine coming home and ever since, dont seem to be losing any antifreeze and just changed oil sunday and found no water in the oil. the antifreeze however is very dark brown, could barely tell the rating which was -22 degrees so im thinking the coolant froze, engine got hot, and coolant thawed and started to circulate. the car has not got hot since that incident however my main question is the car has had a random misfire that comes and go since it got hot, never once did it before it got hot on cylinder number 6 (the back one) so its damn near impossible to thread my compression gauge hose into. Thinking it could be a head gasket or intake but like i say theres no water in the oil, and i dont seem to be losing antifreeze. also heat stays hot and car does not go above thermostat temp. (190ish) any ideas? i dont want to throw alot of money into it if its an intake or head, only 600 into it. Could also be a spark plug or coil or wire but think its weird it started doing it after over heating.
Overheated, Misfire
- Thread starter bracy67
- Start date
Badgers4life
New member
when you say "overheated" what exactly happened?
"My main question is the car has had a random misfire that comes and go since it got hot, never once did it before it got hot on cylinder number 6 (the back one) so its damn near impossible to thread my compression gauge hose into."
Try Switching the Coils to see if the Misfire moves with the Coil, if it does then the Coil is bad.
You can do that with the Spark Plug Wires also, Keep track of which wire came from where so you can determine which one is bad
or get a wire off the Parts Car and use the different wire on Cylinder #6 to see if that clears it up
Lack of Compression shouldn't give a misfire code.
Try Switching the Coils to see if the Misfire moves with the Coil, if it does then the Coil is bad.
You can do that with the Spark Plug Wires also, Keep track of which wire came from where so you can determine which one is bad
or get a wire off the Parts Car and use the different wire on Cylinder #6 to see if that clears it up
Lack of Compression shouldn't give a misfire code.