Propane Refrigerator failure
We purchased a Crystal Cold propane refrigerator about ten years ago so that we could get through the long low-sun periods of Vermont without regular generator use. Suddenly, the refrigerator has failed. We've cleaned the flue, the burner and the orifice without improvement. We've "burped" it by letting it sit on its side, then top and then first side again for 30 minutes each. No help. It lights but the flue doesn't seem to be at normal "high heat" --- gives no significant cooling. Perhaps one clue is what looks like maybe a small rust stain on the rear, possibly starting at a tube weld and extending down? We've never seen anything dripping, or anything on the floor, but don't remember this "feature" when new - and wonder if it is likely evidence a new and very slow leak. Other than that, we wonder about possible thermostat failure.
No propane service people known within reach, so we're looking for advice on how to best proceed. In other discussions I've seen mention of replacing components but am not sure how to diagnose and what to get, or whether replacement of a thermostat or cooling system is practical. If a new unit seems warranted, any tips on the relative merits of Crystal Cold versus EZ Freeze (or other 18 cf +/- options) would be appreciated.
Thank you for any help.