To Pre-Heat or Not?, That is the Question.

[Thomas M]

A diesel tech told me that heating the engine with a block heater could aggravate or cause or accelerate some sort of galvanic or electrolytic corrosion within the engine. He recommended not doing it unless the temperature is really cold. Just to be clear, this is the type of heater that fits into one of the plug holes on the back of the block and has an electrical coil in the coolant and uses AC current...about 400 watts.
Is it advisable to NOT heat the engine if the temps are mild???????

Thoughts on this, please.

[surfcam]

I don't see that happening. I've worked a little bit with corrosion on vessels and pipe lines. It's more of a DC thing. You can't plate anything and sacrifice the anode with AC current. That is what the electrolytic corrosion is. Galvanic can be accelerated with DC current as well. There is some corrosion in a car caused by friction. DC current flows and parts of the car are sacificed. Salt and water helps the process along. For $200 you can buy a annode and DC charger that is said to slow the process down when installed in your car. The heat from the block heater may cause a small amount of accerated corrosion but I put it on the very small side. Starting a cold engine is a way worse oppostion.

[82vdub]

Over 400k miles on ole 82 and that gets regular block heater use every fall and spring until the temps warm up. The car is parked in the snow months, but it's still going well. I think Surfcam said it best, but if there's galvanic action going on, it's not done anything that I can detect with my car.

[FineFrank]

If you're worried about it, use an oil pan heater instead. It warms everything from the oil up-and warm oil flows. One like this:

http://www.amazon.com/Kats-24150-Watt-U ... B000I8TQD6

Thank your mechanic, and continue using the block heater. It won't hurt a thing.

[Thomas M]

Kind of what I suspected..............

I've been doing it religiously for 290,000 miles since new in 1991.

The oil pan heater looks interesting as I have wondered if the oil gets any heat from the block heater.....heat moves from hot to cold so I guess it would have to slither through the oil pan into the oil........not too likely for a short preheat.

I estimate that the block heats to about 120F degrees with the 400 watt coolant heater.... in my climate zone....the Pacific Northwest, USA.