Hello everyone, my truck has a very noticeable loss of power whenever I turn on the A/C, and it also makes a very loud sucking noise while I'm accelerating with the A/C on. It is the same sucking noise that the truck makes if I drive off with it on a cold day without letting it warm up. The Idle air control valve, the Throttle position sensor, and the coolant temperature sensor have all been replaced within the past 1-3 yrs with AC Delco ones. The A/C works well while this happens, it might just need a tiny bit of refrigerant, but it's cold enough for me. The A/C compressor was replaced I believe in 2007 or 2008 with an aftermarket one from Advance Auto, but I am thinking that it may be the problem because the clutch sometimes engages kind of weird. Sometimes it takes a while for it to engage, and it makes a very loud, unusual click when it does. I would appreciate any help, thanks.

 

A/C compressors need oil along with freon, if not enough oil was put in it could kill the pump again. as far as that noise goes, it almost sounds like a bad vacuum leak which will of course make you lose power. heres a slight suggestion to try and find it, pop the hood start the truck, have someone stand next to the truck , while they are there- put the truck in drive and slowly power brake it, till that noise starts if it does.. the person outside should be somewhat able to pinpoint the area. and even though the a/c is cold enough it couldnt hurt to have it evacuated completely and have new contents put in, BUT if the clutch on it is`nt working correctly then that will be a waste of money. Some shops not sure where you live, have machines that can drain out all old freon and oil and re-install it..Good luck keep us informed on what ya do and find..

 

ok, so after hours of searching on here, I read that the sucking noise could possibly be a bad fan clutch. I went to my mechanic, and he said that the radiator fan clutch is fine. he also added a small amount of refrigerant to my a/c. it blows a lot colder now, but I noticed that the clutch on the compressor only turns on on the lowest a/c setting. And when it turns on the lowest setting, it switches very quickly on and off. The a/c blows cold on all settings, but the clutch only engages on the lowest speed on Max a/c. I would greatly appreciate any help. Thanks.

 

I think you might be having the same problem as on the A/C problem thread sounds like there is a blockage in one of the A/C lines. This causes the compressor to short cycle like that.

 

In one of the a/c tubes there is a filter, ( i believe if i`m not mistaking called an orifice filter) that may be dirty.. If i`m incorrect on the name of it i apologize in advance. If you decide to check that I`m pretty sure the whole system needs to be evacuated and then filter cleaned and all new freon and oil installed..also just out of curiosity, how did the Mechanic check the fan clutch for the sucking noise? did he just shake it back and forth for pay in the bearing? a veh with a fan clutch ( While the engine is cold)you can actually have someone hold the fan clutch while someone starts the truck, hold the fan for a few seconds and then let go see how fast the fan starts to spin, if it starts really fast than good if it takes forever than the fan clutch is weak. I replaced one on a friends 95 blazer that would actually stop turning as the engine was running at operating temps and cold... if your willing to give that a try reply back with the outcome..when the eng is cold the fan clutch should be kinda hard to turn by hand, once its warmed up it should spin easily..