OK Guys...I'm baffled. I have read through the forums, but haven't found anything exactly like my problem. Most of the fixes I've found, haven't worked.
Here's what's happening: I have a 95 Cobra SVT 5.0. I put in a new short block 2 weeks ago, and have spent the last week rebuilding the T5 and getting it installed. I drove it for the first time yesterday so it has less than 45 miles on it. But today it started overheating BAD. There is no steam, no leaks, no blown gaskets. I checked the head compression and all cylinders are running 90-110psi and holding the pressure. I've checked for vacuum leaks and found nothing (I even sprayed carb cleaner all over the engine looking for leaks). The water pump has no visible leaks, no sign of bearing wear, and is pumping water through the heater core. During the engine build, the pump was inspected and all looked good. I replaced the thermostat (TWICE - once with a 180 and now with a 195), still no change. I put in a mechanical temp gauge to rule out a faulty dash gauge, and it's showing the same results. I've replaced the temp switch and the temp sensor. I checked the oil for water and it's clean and golden clear. There is never any dieseling or knock. All in all, everything looks good. Except that it's getting extremely hot, extremely fast.
When it heats up, and it really heats up fast, it never seems to open the thermostat. At 210-220* the upper rad hose is still cool and flimsy. I'm not seeing any flow in the radiator, and it's not kicking on the fans. I ran the diagnostic and the self test kicked on the fans with no problem and showed no CELs. I directly connected the fan to power and ran it on high to see if it would help reduce the heat, but it didn't help.
Here's the strange part - when it heats up, it will go to about 212*, hang there for about 30sec, then JUMP to 230-240*. I turn off the engine asap when this happens.
This is the strangest overheat problem I have ever encountered and I am totally out of ideas.
Sorry this is so long, I just wanted to show what all has been done.
Any ideas??
Here's what's happening: I have a 95 Cobra SVT 5.0. I put in a new short block 2 weeks ago, and have spent the last week rebuilding the T5 and getting it installed. I drove it for the first time yesterday so it has less than 45 miles on it. But today it started overheating BAD. There is no steam, no leaks, no blown gaskets. I checked the head compression and all cylinders are running 90-110psi and holding the pressure. I've checked for vacuum leaks and found nothing (I even sprayed carb cleaner all over the engine looking for leaks). The water pump has no visible leaks, no sign of bearing wear, and is pumping water through the heater core. During the engine build, the pump was inspected and all looked good. I replaced the thermostat (TWICE - once with a 180 and now with a 195), still no change. I put in a mechanical temp gauge to rule out a faulty dash gauge, and it's showing the same results. I've replaced the temp switch and the temp sensor. I checked the oil for water and it's clean and golden clear. There is never any dieseling or knock. All in all, everything looks good. Except that it's getting extremely hot, extremely fast.
When it heats up, and it really heats up fast, it never seems to open the thermostat. At 210-220* the upper rad hose is still cool and flimsy. I'm not seeing any flow in the radiator, and it's not kicking on the fans. I ran the diagnostic and the self test kicked on the fans with no problem and showed no CELs. I directly connected the fan to power and ran it on high to see if it would help reduce the heat, but it didn't help.
Here's the strange part - when it heats up, it will go to about 212*, hang there for about 30sec, then JUMP to 230-240*. I turn off the engine asap when this happens.
This is the strangest overheat problem I have ever encountered and I am totally out of ideas.
Sorry this is so long, I just wanted to show what all has been done.
Any ideas??
