AC Issue - Clutch/Compressor...?

[Ozz]

Greetings,
I recently changed my AC condensor - it had a leak - and then had a reputible shop evacuate and recharge the AC system. I did not add any PAG oil when I changed the condensor so they added some.

The AC works great now but when the compressor first engages after the car sits awhile (during work or over night), there is a god awful noise for about 2 seconds. It's hard to describe but it isn't a squeal - more like the clutch is engaging and the compressor doesn't want to turn - like a growl/grinding noise. It drags down the engine rpm until it 'clears up' a couple seconds later.

I'm wondering if there might be too much oil in the system such that the compressor is hydro-locked at startup... never heard of such a thing happening but it just sounds like the compressor won't turn and is really taking a lot of power to get it going.
I guess it could be a compressor clutch issue - but it's fine the rest of the time. Once the problem clears out at start up, I can turn the ac off and on without any issue - until the car sits for several hours... and then it does it again.

Sure, I need to put my head under the hood and have someone else start the AC so I can see what's happening... it was 28 degrees when I got up today so I didn't think an AC test would be valid.

Has anyone else experienced anything like this?

[fastblackmerc]

Greetings,
I recently changed my AC condensor - it had a leak - and then had a reputible shop evacuate and recharge the AC system. I did not add any PAG oil when I changed the condensor so they added some.

The AC works great now but when the compressor first engages after the car sits awhile (during work or over night), there is a god awful noise for about 2 seconds. It's hard to describe but it isn't a squeal - more like the clutch is engaging and the compressor doesn't want to turn - like a growl/grinding noise. It drags down the engine rpm until it 'clears up' a couple seconds later.

I'm wondering if there might be too much oil in the system such that the compressor is hydro-locked at startup... never heard of such a thing happening but it just sounds like the compressor won't turn and is really taking a lot of power to get it going.
I guess it could be a compressor clutch issue - but it's fine the rest of the time. Once the problem clears out at start up, I can turn the ac off and on without any issue - until the car sits for several hours... and then it does it again.

Sure, I need to put my head under the hood and have someone else start the AC so I can see what's happening... it was 28 degrees when I got up today so I didn't think an AC test would be valid.

Has anyone else experienced anything like this?

Either take off the belt and see if you get the noise or disconnect the A/C compressor clutch and try it.

[Marauderjack]

I'll bet it is overcharged......happened to me....HORRIBLE groaning!!

Totally evacuate the system and put the exact amount on the tag under the hood back in it!! Mine calls for 38 ounces with oil!!

Good Luck!!

[Ozz]

I'll bet it is overcharged......happened to me....HORRIBLE groaning!!

Totally evacuate the system and put the exact amount on the tag under the hood back in it!! Mine calls for 38 ounces with oil!!

Good Luck!!

If it's overcharged, can some R134 just be taken out or does it need to be completely done over?

My hood tag is gone - along with my original hood... so perhaps they didn't know how much oil and R134 to put in...

[Marauderjack]

Someone with conventional gauges can adjust it for you but most FORD dealers use a machine that completely evacuates the system and they then recharge with whatever it calls for on the hood tag........easier and much cheaper to teach "Goofball Techs" how to do it with the machine!!

[fastblackmerc]

I'll bet it is overcharged......happened to me....HORRIBLE groaning!!

Totally evacuate the system and put the exact amount on the tag under the hood back in it!! Mine calls for 38 ounces with oil!!

Good Luck!!

Good catch Marauderjack!

[Ozz]

I've got a low pressure side gauge and the Ford Service Manual that shows me what the pressure should be at different ambient temperatures so I think if the gauge shows that it's overcharged, I may bleed it a little and see what happens.

Thanks!

[Curless]

Take it back, have them evac and recharge it with the correct amount of Freon....its over charged and they should make it right. You can't guess at the right amount by watching gauges. You paid them to do it right so have them do it right.

[Ozz]

Yea, I'll give them a call and see what they say.
It's more an issue of making time to take it in again that makes me consider attempting to do it myself.

[Dereck]

Hi Ozz

You might find This thread of interest.

As an addendum my compressor still goes hurhrummmmpphhh occasionally but not as often as it used to, my Excursion does the same thing.

Regards

Dereck

[Ozz]

Dereck,
Yea, that's pretty much it.... as someone suggested - and I suspected, liquid refrigerant in the compressor due to being overcharged is providing excess resistance when trying to start the compressor as you can't compress a liquid.
My problem exactly.
I guess need to take it back in and have them take a couple ounces of R134 out.

Thanks

[Ozz]

Ok, I took the car back to the place that evacuated & filled it. They hooked up the machine and watched the gauges while the AC ran and the pressures were right where they should be. They said they'd redo the evacuation & fill and add an ounce of oil too (I guess they added dye but not oil last time). I think he said that 40.6 oz of R134 came out (slightly high but within spec).
When it was done, the gauges were about the same as the first time.

He did note that the pressure side gauge needle was bouncing and that he suspects that a valve in the compressor is sticking open a little. He said that the R134 systems are pretty sensitive to R134/PAG oil levels and that if my system was low all last summer and winter that the compressor could be on it's way out due to lack of lubrication during that time.

He also said that the terrible groan that it has done when I started the AC could be the AC clutch cycling on and off quickly (which is what it sounded like to me) and that the clutch could be about worn out.

So.... If the noise continues when first stating the AC, I may look into replacing the clutch but otherwise I'm going to use it until it quits and then probably replace all the under hood parts.

[Ozz]

So the noise has continued. I have not been able to witness the clutch engage but I have heard a groaning noise (most common), a banging noise (once) and then what sounds like the clutch slipping (maybe?).
I'm not sure if I should swap the clutch in hopes that it fixes the issue or just wait - assuming the compressor is about dead... I'll check the clutch gap first I guess.

[Dereck]

Hi Ozz

A new clutch will not fix it and I am not sure a new compressor will either, as previously mentioned I dropped my charge 4 ounces and allthough it was 90% better with no (noticable) loss of cooling it didn't completely fix the problem, I am not sure what the answer is, I did wonder if for whatever reason if I have ended up with an overcharge of oil but that would be real tricky (and time consuming) to resolve.

Regards

Dereck

[Ozz]

Thanks Dereck. I guess I'll just have to wait for it to quit altogether and then replace the whole system. It sucks but I can't think of much else to try.