Rear main seal or heads gasket? high temp!
 

:confused:Hi everyone.
Ok, so here's the problem.
I recently have been having surging high temp (all the way to the 270 reading!). It climbs shortly after 10 or 15 minutes running the car at idle. When I went for an oil change, the guys told me that I may have blown my heads, head gaskets or rear main seal, since the oil was coming out like chocolate milk! They said its most likely oil and coolant mixing as a result of the leak depressurizing the coolant system causing no circulation and hence no cooling. However after the oil change I looked under the car and didn't see any drippage.
How do I know which one is the problem? How do I effectively diagnose it? Can't make it to the shop because it starts to overheat 2 blocks away from my garage! I need to know because I'm planning to work on the car early spring.
Thanks!:confused:

Re: Rear main seal or heads gasket? high temp!
 

The leak they are referring to is not external, it's an internal leak. You have a blown head gasket IMO.

Re: Rear main seal or heads gasket? high temp!
 

If your car feels fine, coolant looks clean, no loss of oil level, exhaust normal, fan turns on after a few minutes and you changed temp sensor, and it reads way to the right hot, then you might want to try buying an economical temp gauge at autozone under 20 bucks, unplug stock gauge wire, connect new one to the temp sensor, and check the temp on the new gauge"you can just hold it in your hand", I was running super hot so i thought, the new gauge never went over 200, fan kicked in right at 200, where as the stock gauge read about "L" from NORMAL, near red when the fan would turn on, Bad gauge much better than blown head gasket. Stock mustang gauges are notorious for failing, I mean does your oil pressure gauge actually move, im working on a water temp, oil pressure, tach w/ light triple pod cause of this. Hope your as lucky as me and just have a bad gauge.

95 gt 5speed

Re: Rear main seal or heads gasket? high temp!
 

i agree, i've heard of guages crapping on foxes all the time. but given the milky oil, i would have to second the head gasket suggestion.

Re: Rear main seal or heads gasket? high temp!
 

+1...another vote for a head gasket