Hello from Alaska, I have had issues with various sealants as well,in reallycold weather. When a saw is setting at 40-50 below zero, then are run to operating temp. Crazy heat up cool down fluctuation.
Mostly in snowmachines and chainsaws.
Some will find this improper, but I once lost the seal on a Bearcat 340 upper and lower case halves. The backfires were so severe, it would blow the mikuni roundslide carb right wide open. I was 47 below zero. I kept it at about 15-20 mph and it got me home.
I used right-stuff gasket maker, knowing fully well it was not the best choice for resistance to gas. BUT, it said "rated to -65 below zero" on the tube.
That repair is still holding up.
I've since used Right-Stuff on 3 chainsaw builds. I ported an echo cs-530, a stihl ms 310, and an echo cs 6700. All three are running great.
On the echo cs 530, I tore a felt walbro carb gasket, I even repaired that with right stuff. It has no carb issues.
Another time, I got caught in sweepers with a hunting rifle slung across my back. The forearm was torn off the barrel. I sealed it in place with right stuff. A gunsmith had a bear-of a time separating the forearm from the barrel to re-finish that ugly thing. He had to CUT the forearm off the barrel!
Anyhow, it's good stuff and I use it for bush repairs every year, often being many miles from any road or town.
Another top notch sealant in extreme cold is yamabond.
Last three saws sealed with right stuff: