Why do gloplugs only fail when it is sub-zero???

[mobetta]

well, no start this morning.
only three below.
after a few trys, the glo lite didnt come on. So i grabbed a tester, and 2&4 are burned out. I replaced all 5 last winter, outside, when it was -7*F out. Used bosch duraterm from autozoo. made in france.

then, this fall, 1&2 failed. replaced them w/ autolite's, because that is all I could get. so now 2&4 are out- that means 3/5 bosch didnt last a year, and 1/2 autolite's didnt last 2 months.


I am going to drain the rotellla 5-40 and put in Mobil 1 0-40.
so a $60 oil change, 2 more gloplugs, and I might be able to start this ol girl in subzero temps again.

I did finally just install a circulation tank heater, had that going for 1/2 hour this morning. not enough to get her started. I need to pick up a timer today, so it will be ready when I am.

right now she's sitting out there w/ the 1000w tank heater, a 150 watt oilpan magnet, and the rollaway charger cranking.

I suspect she'll fire up in a bit, even with only 3 gloplugs.