I have a Kenmore 7cf chest freezer that, according to the sticker on the back, I've had since 2013. So, it's 10 years old, which is old but not ancient. It spent about half its life as an uncollared keezer (picnic taps inside) and in the second half of its life I built a collar and set up proper taps. I've always used it with a Johnson Controls temp controller (it was the very early days of Inkbird back then, I think). Recently, I noticed some foamy pours and it happened to coincide with moving where the temp probe was. I took the opportunity to add a fan and set the probe in a thermowell in a beaker of water. At that time, I was already getting some frost in one corner of the keezer. I also chalked this up to having a few intermediate temp probe locations before I settled on the beaker of water. However, the unit seems to be constantly running these last few days or weeks, and the temperature is stuck around 42-43°F (setpoint 38°F with a 2°F differential). Checking poured beer temps, it is close to the temp probe reading, a few degrees higher.

I'm wondering if it's worth paying someone to pressure test the cooling loop and potentially recharge it / fix a leak if present. There was no recent change made to the keezer that should have impacted how good the sealing is, and I've never touched the cooling loop. If it's just a small leak and I get another ~10 years out of it by recharing the coolant, I'd be totally fine with that. Even if there's a sizeable leak but the all-in cost of repairing and recharging the freezer is ~$300-$400, I would consider it. Unless I can find a close match, I'd have to rebuild a collar. So the cost would be close to a wash. Believe it or not, my biggest emotional connection is to the stickers I've accumulated on it.

Just trying to get some opinions from the community, and if there's any additional troubleshooting I can do to figure out if it's low coolant or a bad compressor or something else. In the meantime I'll keep an eye out on craigslist and other places. 7cf units seem pretty common.

Here is a picture of the model information and the inside, showing frost starting from one corner: https://imgur.com/a/7NAMnU0