Our 1992 F350 7.3L IDI--
... has got thermostat problems, again. It's on its third thermostat in the past three years. Once a year it's been in the shop to have it replaced. I don't understand why they keep failing? On a side note, this truck only has 55,200 miles on it to date. It sits quite a bit of the time. It only gets driven for farm work, ie, feeding cattle, putting out hay, moving hay, general around the farm driving. I change the oil and filters twice a year, simply to change the fluids and filters. It doesn't accumulate 5,000 miles annually, obviously.
So my question is, to all the other IDI owners, does the amount of time this truck sits have something to do with the fact that the thermostat keeps failing? This is especially difficult in the winter when these things keeps failing because the old battle wagon is cold blooded enough as it is. Stupid thermostat goes out, and it won't warm up at all. I've stuffed empty feed sacks behind the brush guard to make a grill cover to try and lock in a little heat for it (redneck enginuity, I'm aware. If anyone knows of a decent grill cover kit for the OBS, feel free to pass me some info on that!)
I know Motorcraft thermostats are supposed to fail in the open position, which is what happens since it won't warm up. And I know its had Motorcraft parts used on it because this truck has been serviced at the same Ford dealership that sold it new since day 1.
Any input would be appreciated.