Hello,
I have a 1994 Ford E150 Club Wagon van. It has always run well, and the temperature gauge has always read in the low range, no matter what the driving conditions. The temperature gauge needle has generally pointed at the "N" in the "NORMAL" letters on the gauge.
Recently, however, while idling with the air conditioner running on a warm day, the temp needle went past the middle of the range, pointing to the "A." At the same time, I heard some gurgling sounds coming from the engine area. I turned off the air conditioner, and the temperature reading slowly returned to normal.
A mechanic looked at it. He changed the thermostat, then flushed the radiator and engine block. But this did not help. He checked the temperature sender on the engine block, and he thought that it was ok.
The mechanic did a pressure check, and the system is not losing any coolant. There are no apparent leaks. A new radiator from radiator.com was installed less than a year ago.
Then he noticed that the fan clutch was weak. He changed the fan clutch. This improved the cooling somewhat, but the problem was still there.
At present, I can drive the vehicle on a cool day, and the temperature needle will point at the "N," with no increase. But if the day is hot, or if I turn on the air conditioner, the needle, after pointing to the "N" for 15 or 20 minutes of driving, will suddenly go up to the "M" or "A" and stay there.
Other curious things --- sometimes, the temp needle will not go down until I shut off the engine and let it cool awhile. For instance --- sometimes, turning off the air conditioner will be followed by the temp reading going down; but sometime, the needle just hangs there.
Also --- when the engine is off, but the ignition is turned on --- the temp needle will alowly oscillate, up a little down a little, now on the "O," now on the "R," and then the "O" again.
At this point, neither the mechanic nor I know what to do. He also tried putting in a thermostat with a larger flow area, but this did not help.
Is there some kind of electronic control that allows or inhibits the coolant flow, or is there something else which we might not have considered?
Does anyone have some knowledge about this? If you write to me directly, please send your email to: robert1111 at starcenter.com
Thank you.
Sincerely,
Robert