Hello,
I have a 1994 Ford E150 van, 5.0 liter gas engine. There is an overheating problem that defies analysis.
Normally, my temperature gauge read low, with the needle sticking on the N part of NORMAL on the gauge. It stayed the same in almost any weather or condition. Then, one hot day with the a/c on, the gauge went up to M and A.
A mechanic checked it out. He replaced the thermostat and fan clutch, and he flushed out the radiator and the engine block. The radiator is only about 10 months old, and seems to be ok.
This accomplished nothing. Then the mechanic replaced the temperature sender and the radiator cap. This simply moved the temperature reading up a notch, and the idling engine now read OR on the gauge. But on a hot day, with the a/c on, the temp moved up to MA.
He measured the actual temperature, and found it to be around 205 degrees at the OR level, ad about 217 degrees at the MA level. He said that this was a bit high, but not yet dangerous.
His opinion was that my old thermostat had been stuck in the open position, thus always causing a low tempeature, and that the new thermostat brought things more up to normal. But he could not explain the overheating.
During one of the flushes, he found some thick gunk on the inside of the radiator cap. This was a tan-colored emulsion or oily substance. The mechanic wondered about oil getting into the coolant and possibly clogging something, so he ran a check for hydrocarbon emissions in the radiator water. But apparently there were none. His opinion was that there was probably not a problem with the headgasket, nor with a cracked block. So he flushed the system again, but he did the have the facilities for a high-powered flush.
Then I took the vehicle to the Ford dealer, assuming that the experts must know something. They ran a test and found nothing, and charged me $110 for the useless test. I had them do it again, and this time they measured the high temperature, and managed to say that something was wrong, but they did not know what. They charged $220 total for this, and explained that they charged for their time, and not for any results. They offered to do more tests at more expense, with no guarantee of any true diagnosis, but I declined.
Today, the weather was around 90 degrees, and the temperature gauge went right up to the MA without the a/c on, and later to the L. At this point, I turned the vehicle heater on, which brought the temp back to MA. So things are getting worse.
Also today, another unusual thing: my oil pressure guage, which sometimes reads on the M but usually on the R, today read low, around the NO. Then, on the freeway, before the water temp got really high, the oil pressure guage went up to MO and stayed there. Then, abut ten minutes later, it flopped down to NO, and later down to the middle of the N, staying there.
So there it is, a confusing mixture of things. Does anyone have any insight into this? Any advice would be highly welcome. If you reply directly, please send to snipped-for-privacy@starcenter.com .
Thank you.
Sincerely,
Robert