Hello everybody

Has anyone tried the stick on oil pan heaters from JC whitney? There the only ones I can find on the internet. A friend of mine bought me one of the magnetic type but if you leave them plugged in for to long they can burn your oil. Also looking for a recirculating heater but I have not been able to find one. I would like to at least put the oil pan heaters on my 03 SD 6.0 and 85 6.9 diesels any input would be great thankx.

2003 F250 6.0 FX4
1985 F250 6.9
1976 F150
1975 F250 Highboy