Help! 3.8 Problems


New Member
Dec 11, 2013
So I got a 95 3.8 mustang in pieces and put it all back together and got it running and driving. Then the prob started. Sitting in the driveway at idle everything is fine great heat but once I drive it the temp goes up and it blows cold air once it gets to L in normal it drops back down and I get heat for a min then it starts blowing cold again working back up to the L in normal. Wtf ! Please help
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I've been researching and just found out there is a coolant filling procedure so I'm gonna try that and hope it works. I will let everyone know the outcome thanks for the help
The V6's have a convenient bolt in the top of the coolant system. Slowly loosen the bolt while the car is running, and tighten it down when you get coolant leaking around the bolt threads. Your coolant system has now been purged of air. Check the radiator and make sure it is full as well.

If you have a stock thermostat, the temp gauge should go up to about the "o" in NORMAL, then drop down a bit. If you let the car idle, the temp will eventually go over halfway; the fan should kick on and bring the temp down a little under halfway. If everything in the system is working fine the temp should never get very far past "M", if I recall.

The Mustang coolant system is a pressurized system; if it can't maintain 16psi the temps will rise faster and higher than normal. If you're still having trouble you may want to rent a coolant pressure tester and check out your system. Most times, the hose clamps aren't quite tight enough.