electric heat for motor oil - how effective?

[lancaster,pa]

I'm considering pre-heating my 7.3 with a 120v pad on the oil pan. Will enough heat from the hot motor oil flow up into the engine and warm it and the coolant? If so, to what temperature? How effective would this be compared to using a ZeroStart in the cooling system (would really like to get the engine temp and coolant up to about 140F before starting)? Thanks.

[JimmyDee]

Living in PA, I seriously doubt that it is needed. For what ever reason you want to heat the engine up to 140 degrees, your engine will start without any additional help well below zero.
To answer your question, I don't think the pan warmers will heat the oil to anywhere near 140 degrees. An additional water jacket heater will raise the temp almost to operating temp.
I thought that plugging my truck in would give me a little better mileage in the winter and if it did, it was insignificant at best. It did however give instant warm in the cab.
Jim