Just recently purchased a 1996 V-6 body mustang with a 95 5.0 engine. It seems like it takes forever to warm up, but once it does, it overheats. Sad face!!!! I have flushed the engine and radiator, put new antifreeze and a thermostat in it. Still overheats. Any ideas??
Overheating Problem
- Thread starter Matt Shaw
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jozsefsz
15 Year Member
Radiator is the same for the V6 and GT, believe it or not. The only variations for our years are for Automatic (for the transmission cooler ) or manual transmissions. There's a lot of things that can cause the engine to overheat. And there are a lot of things that can make it look like the engine is overheating.
* The system should be sealed, and take 16lbs of pressure. If the system can't take that pressure, the temperature will rise faster than normal.
* The ECT (engine coolant temperature) sensor could be bad. It tells the car's computer the coolant temp, and if it fails the computer will run the engine hotter than normal.
* The CTS (coolant temperature sender) is only used for the gauge in the instrument cluster. If it's bad, it would only look like the engine is overheating.
* Your new thermostat could be bad, though unlikely.
My first check would be to buy or borrow one of the pricier code readers, one that can read PIDs. That feature will let you see the output of the ECT. Next, I would buy or rent a radiator pressure tester kit. As its name implies, it will let you test how much pressure your coolant system will take. If it can't take 16lbs of pressure, you'll find a leak. The leak will usually be a hose clamp that isn't tight enough or a pinhole leak in a hose.
* The system should be sealed, and take 16lbs of pressure. If the system can't take that pressure, the temperature will rise faster than normal.
* The ECT (engine coolant temperature) sensor could be bad. It tells the car's computer the coolant temp, and if it fails the computer will run the engine hotter than normal.
* The CTS (coolant temperature sender) is only used for the gauge in the instrument cluster. If it's bad, it would only look like the engine is overheating.
* Your new thermostat could be bad, though unlikely.
My first check would be to buy or borrow one of the pricier code readers, one that can read PIDs. That feature will let you see the output of the ECT. Next, I would buy or rent a radiator pressure tester kit. As its name implies, it will let you test how much pressure your coolant system will take. If it can't take 16lbs of pressure, you'll find a leak. The leak will usually be a hose clamp that isn't tight enough or a pinhole leak in a hose.
jozsefsz
15 Year Member
The reason I ask about the radiator, is that it having been a v6, there's a good chance it blew a head gasket before the swap. If it's the original radiator, there's nothing better than a can of 'block sealer' to have destroyed it. 
I'd also guess that the v8's running with the '95 OBD-I computer, so I don't think a PID-reading code-reader is available? (I've never checked since I have a quarterhorse which does the same).
The fan question is important, because it's possible someone didn't swap in the right CCRM or that the pinout's screwed up.
All of Cythar's feedback is very good too for troubleshooting general overheating issues. My feedback was more focused on what someone can potentially screw up doing a v8 swap.
I'd also guess that the v8's running with the '95 OBD-I computer, so I don't think a PID-reading code-reader is available? (I've never checked since I have a quarterhorse which does the same).
The fan question is important, because it's possible someone didn't swap in the right CCRM or that the pinout's screwed up.
All of Cythar's feedback is very good too for troubleshooting general overheating issues. My feedback was more focused on what someone can potentially screw up doing a v8 swap.
The reason I ask about the radiator, is that it having been a v6, there's a good chance it blew a head gasket before the swap. If it's the original radiator, there's nothing better than a can of 'block sealer' to have destroyed it.
Good point. OP did say he flushed the radiator, but it still could be plugged.
The 94-95 computer does show PIDs, just not as many as an OBD-II computer. I can read my ECT value with the Autoxray EZ-Scan 5000 I bought some years ago.
I don't know if the car will run with a V6 CCRM, but it's a valid thing to check. You can do a V6 to V8 swap fairly easily with a donor car, but it's always possible someone did it cheap or did it wrong.
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