Hi All,

I got my A/C charged today and it all went well - while the car was running and the A/C was on. After charging it and running the air for 20 minutes, I shut off the air while getting transmission pressures for my builder. After 10 minutes, I turned on the A/C and got squeal/thump, squeal/thump, etc. Not sure what's happening, I suspect either I have too much oil (hydrolocking) or the tensioner is trashed and not keeping the belt tight (however this was NOT an issue during the initial charging). Here are the normal and A/C vids so you can see what's going on.

It's a Vintage Air Gen II Supercooler universal kit minus compressor. The compressor (Sanden SD-508) was bought in '06 but had never been used until today. The outfit I got it from (SavannahAutoAir) is no longer in business, but I have all my old e-mails from them. It was originally built for R-12, and they mentioned to remove the mineral oil and refill with PAG-46. I pulled the fill plug, dumped all the oil I could, ran 2 oz of flush through it (turned it over 10 rev's by hand), dumped the flush, sprayed ~ 1 oz or so of BrakeKleen in it (turned it over 10 rev's by hand again), dumped the BrakeKleen and blew it dry with compressed air. Then added 8 oz PAG-46 (as per SAA) to the compressor. Seemed like a lot, but my system is all new and bone dry. Turned it over 10 rev's by hand again with no binding or hard spots. Vacuumed for 15 mins, held vacuum for another 15 mins, then added 24 oz of R-134 (Vintage Air calls for 28 oz).

Thanks!

Russ

 

Not sure what your problems is, but a comment on the oil, you usually split the oil into two parts..(of the system total requirement for oil), 1/2 into the compressor and the other 1/2 in the filter/drier.

I would think 6 to 8 oz. total would not be out of spec... but you should check with VA on this.

I would check out the AC compressor's clutch and belt....

 

Did you put the oil in before you pulled a vacuum on the system or after? I add the oil after because you can suck some of the oil out when you pull a vacuum on the system.

 

Does it ever stop doing this? If you rev it up does it get worse? My car is doing about the same thing, but after you drive it with the air on for a while the problem goes away. Vintage air said I might have oill draining back down to the compressor and hydrolocking it due to it being mounted low. They said it should only have 7 ounces of oil in it, and I put a little in the other parts of the system during assembly. So I drained some oil out, still no go. We're leaning toward a bad compressor now, but VA said they would warranty it. Mine will freeze you out of the car, but on initial start up it will almost completely stop the serpentine drive (slips on the crank). I guess I'm going to put a new compressor on it and hope that fixes it, but I'm not going to do it until late in the year when I'm not driving it. Keep us posted and let us know what you find out.

 

Oil went in first, but since there was no oily residue coming from the vacuum system, I'm sure it's all still in there.

It's f'ed up... My system pressure (static) was down 40# (to 110#) overnight, so something's leaking now. Either the seal blew or the case is cracked (can't tell if it's a casting flaw or crack). I removed the freon, pulled the compressor off and dumped the oil. It's turned a little brownish but doesn't smell burned. Turns over great with no binding and seems to pump OK. Put everything back together and cannot hold a vacuum (drops 2" / 30 minutes). Only got 20 minutes runtime on all new parts, but when it ran, it ran great. Had 25# suction and 225# discharge. Guess I'll be compressor shopping!

Russ

 

I wonder if there is some sort of mix up with how much refrigerant was put in. That compressor is meant for R12 and R134a was used. Im not sure, but I think that different volumes of each should be used.

The VOLUME or refrigerant used isnt really as important as the PRESSURES and TEMPERATURES that the system runs at. The volume of oil is damn important tho, and if you put the recommended amount in, then you must have got it right. It may be possible that the system had too much refrigerant in it and when you shut the car off liquid settled out and you hydro locked the compressor.

I am not too sure about the cleaning it out with brake clean and blowing it with air tho. That may have been damaging to the compressor, but I cant say for sure.

 

No mix up on the freon, Vintage Air specs 28 oz., I put in 2 cans (24 oz.) and was gonna put in the rest but encountered the "problem" and quit.

I never saw a spec from VA on oil, only the guy who sold me the compressor. He spec'ed 8 oz. and I have no way of knowing if that's OK or too much (he's long since gone out of business). Your statement made me realize that my compressor is actually the low point in the system and that hydrolocking may be unavoidable!

Sanden says to flush with generic flush or brake cleaner, so I'm good there...

Russ

 

Keep in mind that GM LS motors come from the factory with the A/C compressor mounted at the bottom of the engine.

 

S10xGN, Im pretty stumped by your problem. Must be too much oil in the system (somehow), or the compressor got hydrolocked (somehow). Sounds like you covered your bases pretty good to me. Let us know what you find.

 

Is it possible that the compressor was already prefilled, then you added 6-8oz?

http://www.sanden.com/index.php?id=34EMNHQTC

 

Which oil did you use? The R-12 oil is incompatible with 134 refrigerant, and will ruin the compressor in short order. With 134, you have a very limited choice of refrigerant oils that will work with it. POE or PAG oils are about the only ones that can be used. Use of any mineral-based oil will assure failure of the compressor. If you did use a mineral based oil, you will have to flush all remnants of the oil from the system and replace the accumulator/drier. Even a small amount to mineral oil left in the system, can trash the new compressor. The same compressor is sold for both R12 and R134 applications, so it is possible that your compressor already had mineral oil in it. I have never bought a Sanden compressor that was not already pre-charged with oil.



Regards, John McGraw

 

Yes, the compressor was prefilled. As stated above I drained, flushed, and refilled it.

Again, this was all covered in my first post.

I've since pulled the compressor off again and it spins & pumps good. I pulled 30" of vacuum yesterday at 17:00, and today at 17:00 it's at 26". I ordered a Katech tensioner yesterday that will take the belt slop out of the picture, then we'll see how the system behaves.



Russ

 

If you lost 4" in 24 hours, Id call that a leak. If you got some leak detector or something Id put that in before wasting time and money of refrigerant. The way that thing was jumping around in that vid I wonder if the seal is damaged now.

What have you done about oil this time?? Did you flush the compressor again and clean it out again??

 

Yeah, I'm thinking the seal may be wrecked, but I haven't done anything yet, I'm on day-shifts this week... I did call S&P (who made the compressor mount brackets) and they were very interested in my situation. Enough so to send me a manually adjustable tensioner at no charge.



I don't see where I ever mentioned the mounting, it's not stock at all. The S&P setup mounts the Sanden 508 real tight to the block and does not use the factory (inner) set of grooves on the damper, instead it uses a much longer single belt setup. There is, however, plenty of belt "wrap" around the A/C pulley.

Russ

 

UPDATE: Got the S&P bracket yesterday, spent this morning modding it to look like a factory piece. Got it installed and no more belt bounce! The system cools great and runs as expected. Don't know if it was a design problem (longer belt) or weak factory tensioner, but it's right for now! Guess I'll be returning the Katech piece when it gets here...

Russ

 

Glad to hear you got workin again, it always feels good to 'score one for the good guys' once in a while.

How is your pressure holding in there??? Got any leaks?

 

It's got a leak somewhere. I've got a bud with a sniffer, just need to catch up with him...

Russ