Has anyone experienced AC compressor slugging on their trucks?

 

what do you mean "Slugging"

I have a leak in my high pressure AC fitting that I am putting off changing, so my R134 is often low.

 

Slugging is what happens when the compressor fills with freon/oil and upon the initial compressor cycle all that liquid material is shoved through the system. It seems to only be a problem for compressors which are mounted low on the engines. These trucks happen to be that way.

Slugging can be recognized in many forms too. Noises ranging from rattling to an occasional thump. My truck started this thumping noise on the passenger side firewall area when I first turn on the AC, but no other time.

 

Mine never has............

 

Haven't noticed on mine....

 

Mine never has

 

Well you guys are just no fun.....

 

Never noticed it either.

I can see this happening if the system is overcharged with R134, or too much oil (or incorrect oil for that matter) is put in the system during a component replacement. Too much refrigerant charge, the refrigerant will stay in a liquid state much longer in the evaporator. This means that the evaporator will not cool the cabin as effectivly (need the liquid to gas transition for cooling), and potentially having liquid R134 reach the compressor.

The oil is important as well, the compressor is designed to handle a certain amount of oil going through it as it runs for lubrication and sealing. But again, to much can lead to slugging/hydrolocking. The correct oil is crucial too, which for us/R134 is PAG oil. There are a few different grades of PAG oil as well. PAG 46 (thin), PAG 100 (medium), and PAG 150 (thick). Our Rams use PAG 100 I believe.

 

I would have thought overcharging was the problem too but given that I've had the truck forever and the AC system has never been touched.....only to have the issue arise like it did. But since it stopped its thumping after being topped off, I can only make the assumption that the problem was oil not moving through the system as it should due to the inefficiency from working under low pressure.