Cheap silicone oil pan heaters?

Looked at magnetic ones, decided against it for two reasons. First, the surface area is very small. Second, seems like an awful lot of the cheap ones melt down. ETA: Also, haven't physically looked at one but seems like the magnet could inhibit direct contact and thus heat transfer.

The ones I was thinking about are flat silicone pads with the heating element sandwiched inside. They are adhesive backed. Just clean the bottom of the sump real well and slap 'em on. Good, uniform contact, and greater surface area for heating.

Lol, yeah, been there, done the cold weather caulking thing. :-D

I put a 50 watt silicone heat pad on a pressure washer pump for a mobile washing company once, it kept freezing up on him. Worked great.
I also install larger 100-150 watt units on vehicles that only have a provision for a water-jacket freeze-plug type heater, since they are cheap and you risk leaks or even worse sudden loss of coolant from it blowing out.
The newer cars all have cartridge type heaters that fit into a dry socket in the block or cylinder head.

I use Kat's brand silicone pad heaters but an automotive store will likely hit you for at least $40 for even a small 50 watt. Depending on how cold it is and your water/coolant capacity, a 25 watt one might even work.

I say give the chinese ones a try! Just don't expect them to release easily if it fails.

Here's an example. From the stated power density and size, it's actually around 110w, not 250w as stated in the title. This kind of thing is fairly common from Chinese sellers. But they range from 9 to 12 bucks, might be worth trying. Maybe even put 2 on. Also gotta be careful regarding things like whether or not it already has a plug (and type) and whether the wattage is based on 110v or 220v.

www.ebay.com/itm/110-130V-250W-Engine-Oil-Pan-Sump-Tank-Heater-Mat-Pad-Silicone-rubber-210cm-6KV/264543126057?hash=item3d97ffc229:g:6PsAAOSwxcJd2QdS