AC compressor engaging hard

[TSPowell]

The first time I turn on the AC button everyday, my compressor engages REALLY hard, but everytime after that its fine... untill the next day. Whats the deal, is my clutch going bad. Its been like this for over a year, and everything works fine.

 

[Edgemann55]

It's normal. My 05 has been doing it for 4 years now.

 

[Jeepr]

Yup, that's what they do.

 

[LRutigliano]

It is normal for our trucks to do this, but its not good for the compressor.



What is occuring is that the AC compressor is the lowest point in the system.



When you turn off the system, the refrigerant seeks out the lowest and coldest spot to "hang out" due to gravity.



The refrigerant in the suction line has turned back into a liquid due to the ambient temps and time. When you first engage the compressor, the liquid is flowing into the lowest spot (compressor) and is liquid slugging the compressor. The compressor only like to compress gas, not liquid... that awful noise is the internals of the compressor trying to compress liquid...



Once the system is running, all of the refrigerant in the suction line is a gas and it stops making that awful noise. This is most prevalent in the morning after a fairly cool evening.



A "properly" designed AC system has the AC compressor higher than the lowest spot in the system. Ideally, you want the refigerant in an idle system to "hang out" in the condenser.



Hope this helps,

Louis

 

[Motorhead]

I always do the "first of the day" engagement of the A/C at IDLE because of that. If it is safe and I am running down the highway, I will put it in neutral, let the engine idle down, then turn on A/C for the first time of the day.

Louis... . Thanks for explaining the issue. I never knew why but figured it wasn't good for the compressor. Chris

 

[Wingate]

I'm glad somebody else has heard this same noise... . I've just always assumed it was flash rust on the clutch surfaces since it only does it once every day. After reading the above posts... that might explain it also... .

 

[DValentine]

Thanks for the posts. I have been wondering about this too, on my 98. Thanks Louis, that made a lot of sense.

D

 

[tkerrigan]

I bought a can of refrigerant with gauge last April in Las Vegas because the air conditioner wasn't performing as will as it could have. It took about half a can and it hasn't slammed the compressor since.

 

[Bochuck]

Thank Heaven for TDR members and their information. I have the same problem but couldn't find anything wrong. It's been doing it for 5 years now but still works like a champ. I never thought to bring it up in the forum.