How long should the freezer/fridge stay warm after defrost?

Inglis Side-by-Side style Manufacture Date: 01-11. No icemaker/water dispenser installed. Mechanical timer auto defrost.

My freezer and fridge temps are all over the place. My freezer has been defrosting most items at least once a day (ice packs get melty even). It seems to be related to the defrost cycle which I am told runs every 9ish hours. My landlord cleaned out some ice from the coils,etc and replaced the defrost timer, but no change.

2-3 times a day… The freezer will rise to temps as high as 5C to +7C/44.6F and then take an average of 1.5 hours (sometimes bit longer, sometimes bit shorter) to lower down to -18C/0F and then it usually stays -21C/-4F for a little while.

During this time, the fridge also rapidly rises in temp up to 9C/48.2 (but has even been as high as 13C/55F) and overs around 6 to 7C (43-44.5F) for around 3.5 to 4 hours (sometimes little more or less) and then will get to the maximum safe temp of 4C and slowly drop til the average of about 1.5-2C (34.5-35.5F).

The fridge also rises fast when the door is open even briefly and I don’t hear the compressor kick back on like I have with other fridges. I know that is somewhat normal in summer, but it’s very fast, like from 2C all the way up to 9C and often takes hours to cool. This is using 3 styles of thermometer and getting about the same readings.

I think this is not normal operation. I know temps get can pretty high in defrost, but I’ve been reading the MAX freezer temp should be around 0C/32F and it should not stay there long. I also read the fridge should only be rising to about 4.5C/40 to maaaybe 7C/44.5F and only for a short time.

So! My question - How long should the freezer stay below -18C/0F after defrost? How high and how long should the fridge be warming up?

What would be reasonable to try next? Thermostat Assembly? Bimetal Defrost Thermostat? Damper assembly or fans? I know it’s hard to guess especially without looking at it, but I’m hoping someone has dealt with a similar problem and can help. :)

We are a small family and don’t always go through food very fast and it’s worrisome with milk products, meat, etc. Right now I’m borrowing fridge space but it can’t last!