[Piwoslaw]

I had a chance to get under the car today, so I used my new IR thermometer to check how the heating pad is working. I preheated the engine for an hour before driving two houses down the street to my brother-in-law's garage. By the time I got under the car and took the engine tray off, the oil pan and heating pad registered 26.6°C, while the rest of the car was between 10°-15°C. I plugged the pad in and its temperature started to rise very fast. After about 3-5 minutes it was almost 200°C, while the oil pan was 55°-75°C, depending on how far from the pad.

I've been monitoring engine coolant temps just after start-up and it seems that the oil pan heater doesn't have much effect on those, the difference is noticeable after a few seconds when the coolant hardly cools once it starts to flow through the engine. In fact, the coolant+oil pan heaters in tandem work so well that my engine hardly notices that the glow plugs are faulty - the ECU only throws a code after a cold start. Absolutely no problems when starting the engine, only the battery's age (6 years, of which at least the last 3 had really cold winters) is starting to catch up - sometimes, after killing a warmed up engine at a red light, it turns 2-3 times before it catches on. Gotta start researching replacement options. I'd invest in a deep cycle battery only if I could turn the alternator off, otherwise I don't think it is worth the extra cost.