12v Silicone rubber heater pad on oil pan
 

So there is a lot of talk about block heaters etc. Which are fine so long as you aer near power. But what if you are not.

I'm looking to decrease warm up time for my TDI VW 140pd engine.

I've already purchased one of these heater pads. (search ebay: 250w 12v silicone heater pad)
And they get very hot, reasonably quickly. They have a small thermistor that turns them off at a specified temperature, they click, like a tiny relay.

I wanted to put one of these heater pads on my oil pan, on a timer (press the button once, and it activates a relay for 10 minutes and then turns off) to try warm up the engine oil faster during cold starts.

I plan on making a bracket to press this up against the pan. Along with high temp silicone sealant around the edges to keep it sealed. Maybe with insulation on the other side (non pan side) to keep all the heat in instead of wasting it warming the air around it.

The extra current draw on the alternator also means more load which = helps warm the engine up faster too. My only worry is if I overload the alternator. 14v @ 250w = ~18 amps. So I should be fine?

Any thoughts and considerations.

I doubt it would save fuel - ultimately you're burning more fuel to heat the engine up more quickly, to save fuel. If it's to reduce engine wear, you're running the engine harder for a bit while it's cold to make it warm up faster, so I don't think you'll come out ahead from that perspective either. The only place it might help is if you simply can't get it to warm up, but I don't think it gets that cold in the UK?

I just installed a 120v one on mine, which I combine with a block heater. They're on a timer together, and turn on a little while before I get up in the morning.

http://i.imgur.com/v5k0q2Y.jpg

http://i.imgur.com/NyVSaaV.jpg