Do window a/c units thump when they turn off?

Nearly all a/c units do that. Mine does that every now and then and it is only 2 years old. The compressor uses a lot of power, and once it shuts off. it does make that noise

You seriously have no life FRANK seems like all you do is be on yahoo answering questions with ignorance no advice what so ever just to get points who does that, you must be a lonely person with no one who loves you since all you do is spend your time on the computer trying to bring others down then you want to report comments like the little ***** you are lucky for you this is the internet since you seem like one of those people who walks around with their head down whispering to themselves because they don't have the guts to say what they think out loud if they were face to face with you and NO this is not a threat or harassment since you seem the type to try to take this to the highest degree of "punishment" this is simply freedom of speech and publication and exposing you to everyone who reads this before you go and complain to yahoo for them to take this down lmao. Get a life this is supposed to be a safe place for people to use their freedom of speech to post questions and get answers without criticism from dumb asses like yourself.

It thumps because it vibrates. Try securing the entire unit a little better, so that it can't move when the compressor cuts on and off. The compressor is sitting on rubber isolators to minimize this problem. In some older units the rubber isolators may be worn out.

That's not unusual. I have used window units that thump or shudder when the compressor cuts off. It's due to how the compressor is mounted inside the unit.

Make sure your window unit is mounted securely in the window.

Hi Frank, Your window a/c should not be thumping when you turn it off. Depending on the age and cooling capacity, it may be cheaper to buy a new, quieter one than to have someone take a look at it and repair it. Also, the newer model may be more energy efficient. Good luck with either option and I hope it is not too expensive.

Yes its normal it happens with ptac units and camper air conditioners too your girlfriend must have very sensitive ears

A lot of the window units do that..Have no idea why but even as a kid I can remember these units doing that,,

I've seen (heard) some that do that.

It doesn't necessarily mean the air conditioner is about to fail.