01 Suburban Ac Troubles

[ScottyBoy]

I have a 2001 Suburban with the rear AC and about a month ago I noticed a loud chattering noise upon acceleration. I narrowed it down to a faulty AC belt tensioner. I replaced it with a Dayco unit and it literally exploded all apart later that day as I was driving. I install another one. Same thing happens when I get it over 3k rpms. I found a TSB eplaining all of my symptoms and it said there was a design flaw in the compressor that caused liquid slugging. That then causes extreme stress on the belt and tensioner. So now I basically realize I need a new compressor. Due to the outrageous repair quotes I got from several shops, I decided I have to talks this on my own. I found a shop that agreed to evacuate all the refrigerant and let me replace the parts then come back to him and let him vacuum the lines and charge it back up with 134.

Fast forward to yesterday. I finally got my new AC Delco (actually made by Denso) compressor, drier and orifice tube delivered from Rockauto (best parts site ever BTW) and had the shop evacuate all the refrigerant out. The shop said if the orifice tube is really dirty, then I should bring the truck back to him and let him flush the lines. So my question is: How dirty is really dirty and what would be normal for an 11 year old truck? I took it out and it seems all clean except for some metal shavings. Should I have it flushed?

 

 

 

I held it up to the light to show that there is no dirt or sludge in it, just those metal shavings.

[Jsdirt]

Here's what I would do.

 

Take that new compressor to the bench before you install it. Turn it upside down & let any factory oil drain. Then pour in the oil you plan to use & turn the compressor clutch several times in each direction by hand, and drain that. Repeat as necessary.

 

Replace all the o-rings and seals on every part you disassemble. Make sure to lube each o-ring before assembly. Buy a brand new parallel-flow condenser, new orfice tube, & new accumulator. Now you have replaced all the part that trap debris. Find out how much oil is required & divide the oil up amongst the compressor, condenser, & accumulator, install the parts, vacuum down & charge her up.

 

With that you should have years of trouble-free ice cold A/C.

[ChevyTech77]

Have it flushed. Most compressor's will not be warrantied for failure unless the system is flushed anyway.

[ScottyBoy]

Here's what I would do.

 

Take that new compressor to the bench before you install it. Turn it upside down & let any factory oil drain. Then pour in the oil you plan to use & turn the compressor clutch several times in each direction by hand, and drain that. Repeat as necessary.

 

Replace all the o-rings and seals on every part you disassemble. Make sure to lube each o-ring before assembly. Buy a brand new parallel-flow condenser, new orfice tube, & new accumulator. Now you have replaced all the part that trap debris. Find out how much oil is required & divide the oil up amongst the compressor, condenser, & accumulator, install the parts, vacuum down & charge her up.

 

With that you should have years of trouble-free ice cold A/C.

I already have a new compressor, drier/accumulator, and orifice tube that I got from Rockauto. So you these no I should replace my condensor too? And I don't know if this matters or not, but the AC was blowing ice cold as long as I had a belt on it. But it started putting extreme tension on the belt to the point that the tensioner kept breaking.

[ScottyBoy]

And here is what I have so far. The Compressor, accumulator, and orifice tube. The compressor has oil in it, the paperwork says to drain the oil from the old compressor and measure it. Then drain the oil from the new compressor and put the same amount back in that was measured from the old compressor.

 

[Jsdirt]

Only reason I say change the condenser is they are very difficult to flush without very expensive specialized equipment. They are so cheap nowadays it's just a good insurance policy if indeed you have lots of metal in the system from the failed compressor. Don't now what they charge nowadays for a flush, but if they have the equipment to properly flush a parallel-flow condenser, then that may be the way to go. In cases of black death, or other extreme compressor failure it's better to toss everything & flush the evap. Judging from your tube, yours doesn't look that bad ... so there's a chance you'd be ok without a flush ... but without seeing it in person I'm just taking a shot in the dark here.

 

If it were my $$$ I'd just change it all, & remove the hoses & blast them out with brake cleaner & compressed air. Little to no oil remains in evap but you can do the same there too if so inclined.

 

As for the oil amount I usually throw an ounce in there & run it by hand several times back & forth after the oil flush procedure. Then several ounces in accumulator & the balance in the condenser. Compressor doesn't need a ton of oil in it to live. An ounce is plenty after the oil flush. Once you charge it all that oil will be moving from the accumulator, to the evap, & back to the compressor in short order.

[ScottyBoy]

My mechanic said that it was such a small amount of metal that there was nothing to worry about. So I did not flush it. I changed out the compressor, drier, orifice tube, and all the O rings under the hood. I put 4 oz. Of oil in the new compressor, and 2 oz. In the drier/accumulator. I then took it back to my mechanic and he put a vacuum pump on it for about 30-45 minutes. Then charged it up with 48oz. of 134a refrigerant. Now its blowing ice cold again.

 

But now I noticed that the rear AC is not getting cold, but the front will give you frostbite.

I called the shop yesterday and he said he will have to take everything all apart to check it out, but most likely its the expansion valve. I think it was doing this sometimes before the compressor went out too.

 

So how hard is it to change the expansion valve? I am sure I can do it I managed to do the stuff under the hood.

[Jsdirt]

It probably got some tiny pieces in it. But they're pretty easy to change. I've only done rear air on a Ford Expedition, but should be the same on that for the most part. Everything should be under a panel in the back. Will come out with the most basic hand tools.

[ChevyTech77]

Rear evap core has to come out which is not a ton of fun. Sounds like the stuff that was in the orfice tube got back there as well. A flush would probably have got that out.

[Jsdirt]

Yikes ... guess they are different. That's the first time hearing a Ford job was easier than a GM one - usually it's the other way around ...

[ScottyBoy]

Now it seems like the expansion valve is just sticking sometimes. Sometimes it blowing cold but then other times it wont. Screw it, I will just leave it like it is for now. Its still more than cold enough like it is.