DeathRattle

I hope I am posting in the correct section and I apologize if I am not in the right place. Anyway, I have a 1996 Lincoln Mark VIII as well as an 03 Mustang GT and a 1995 T-Bird. I am having overheating issues with my Mark VIII and I am asking help because it has the 4.6 DOHC engine and I am new to the 4 valve engines. I replaced the thermostat, the water pump, the radiator, the coolant reservoir cap, and the engine coolant temperature sensor. I made sure that each new part was operating properly before I installed it. I made sure to carefully burp the system several times (by filling the coolant through the crossover and so on...). I am positive that there are no air bubbles in the system. The temp gauge keeps reading that the car is overheating but there are no boiling sounds from under the hood and no coolant has leaked from the reservoir after I turn the car off. After letting the car sit I return and check the levels again and the levels are all fine. I suspect that I have a faulty temp gauge or perhaps the connection to the temp sensor is faulty. BTW, the fan does come on but the temp gauge does not decrease. I have been scouring the internet for weeks and I have stalked numerous forums for answers but I can't seem to fix this problem. Is there anything that I may have over looked? Could it be a faulty connection to the temp sensor? Could it be ECU related? I installed a CAI so could that be the problem? I noticed that I have no A/C, could that be the cause of my problem? Thanks for any and all suggestions and again I hope I posted this correctly...

DeathRattle

So I went out to my car and cleaned off the connection for the temp sensor and the gauge is still reading that the car is overheating. The fan also switched on and ran continuously. I ran the car until the gauge was almost in the red and checked under the hood and there was no coolant forcing its way out of the reservoir. I also did not hear any boiling sounds from the reservoir or the radiator. I squeezed the upper and lower radiator hoses and they were hot and pressurized but they did not burn me. The check engine light did not come on and there are no codes. Does anyone have a clue as to what the problem could be? I am thinking that it is ECU related but I am not sure. Tomorrow I am going to borrow an infrared temp gun just to see what the temp actually is. In the meantime I'd appreciate it if anyone could tell me what could cause this type of issue. Thanks again...!!

5.0 85 GT

the only thing i cna throw out there...o wait its no a/c i thought u said no heat...i was gonna say a heater core....but nevermind....i would say its a faulty gauge...but is the fan coming on at the right temp to jsut keep the car at normal temp...or does it only ocme on when the gauge skyrockets?

DeathRattle

Well I programmed the fan to come on at 160 degrees as an experiment. I wanted to see when it came on in relation to where the temp gauge needle was. The fan came on and the gauge needle was over 3/4 up so I think it's a faulty gauge. I then ran an infrared temp gun to the engine after driving the car and it went up to 220 degrees but the temp gauge was in the red. Again the coolant was not boiling or forcing its way out of the reservoir. The infrared temp dropped to around 195-205 after stopping the car and letting it idle but the temp gauge was still over 3/4 up. Next I ran my T-Bird for a comparison and it also went up to about 220 degrees but it cooled down to about 185-195 at idle. The only problem is that I do not know what thermostat is in the T-Bird. Is 220 too high for a vehicle to operate at? I was driving the car pretty fast...

dirtydave289

iirc 220 is an ok temp
but wait for someone else to answer

DeathRattle

Thanks Dirty...I'm gonna buy the gauge sensor tomorrow and see if that helps at all...if it still reads overheating then I'm gonna just buy an aftermarket temp gauge because this is annoying...