A/C Experts?

Hey Gang - I need some opinions on some A/C work on my tow vehicle. Air con is not something I'm very familiar with (besides ripping off and dropping in nearest waste bin.)

Our Explorer (1997, 5L V8) recently started having issues with the AC clutch banging and twitching. I know it's about to lock up and smoke the serpentine belt. By the time I buy a pulley and the special tools to remove & install I can buy a new compressor/clutch assembly. My question is: should I go ahead and do the condensor / accumulater / anything else while I'm in there ? It hasn't been cooling very well in recent years, but doesn't leak down. It just takes a long time to get cool and it doesn't blow very cold at its strongest. This isn't a DD for us anymore, but is a backup and sees lots of tow-the-camper duty in the summer, so better AC would be nice.....

So...what other pcs are required replacement to protect the new compressor? What parts might improve performance if replaced?

Thanks guys and gals!

David

It is pretty standard to replace the accumulator when you open the system, and it should be pretty cheap.

You might want to have it pressure tested (or at least test the pressure that is in there to see if any has leaked out) before you take anything apart, in case you need any new connections etc.

(not an expert, just some knowledge)

Replace the accumulator and the orifice tube. Leave the rest of the stuff alone unless it is leaking.

If your comressor lunches there is an inline filter that you can put in on the low side before the comp. Plus one on replacing the reciever/ dryer. Also make sure you evacuate the system before recharging.

a few things..

if it's not cooling well it is almost definitely pressure related. Just because the compressor has not stopped coming on altogether does not mean you have a full refrigerant charge. So, check the system pressure before you take it apart.

In fact, you can pressurize the system with your air compressor to check for leaks before you take it apart if you want to. This will only expose leaks on the low side, though, for the most part.

How are you planning to recharge the system? Are you having someone do it or doing it yourself?

The system is still holding pressure and freon. Looks like right now I'll do all the hardware replacement then take it to a friend-of-a-friend to pull a vacuum on it and check my work, then charge it myself since it's 134a.

No reason to replace the accumulator. This is a myth created by greedy service companies. It may not even have any dessicant in it, which makes it just a hollow tank. Dessicant in 134a systems does not and can not absorb moisture unless there is gaseous flow across it. Since the moisture in any properly evacuated system is minimal, the absorbing capacity of the dessicant is many times greater than what it needed, so re-using one is absolutely acceptable. We test A/C systems continuously for performance, amongst other things, and while we open the system frequently, and have an unlimited supply of driers and accumulators, we haven't changed one in over a year. Don't waste your money. Same with the orifice tube. If there is no visible damage, clean it and put it back in. It's probably better quality than any of the replacements anyway. Don't leak test with compressed air, it's too contaminated. Before you go replacing the clutch or the compressor, jump the clutch to 12v and make sure it has a good ground. If it continues to behave that way then replace it or the entire compressor. If it clears up then that's your problem. Let me know if you want a good deal on a compressor, as we are a Sanden dealer and can also get most other brands.
Jim

Thanks Jim, that sounds like sage advice. Assuming the compressor tests faulty, what's your opinion on replacing the evaporator to avoid debris in the new compressor?

Unless the compressor fails and actually sends crap into the system, there is absolutely no reason to replace anything except for the broken part.

Right now I have a broken A/C clutch on my Dakota. I have it bypassed right now with a different length belt. Now when I finally get money to fix it with a new compressor, I am only replacing the compressor and trying to borrow an A/C machine to evac/recharge it. Piss on the parts stores that force you to put on extra E36 M3 that has no reason being replaced. I would just replace the clutch but it is as much as putting on a new compressor.

Brian

ultraclyde wrote: Thanks Jim, that sounds like sage advice. Assuming the compressor tests faulty, what's your opinion on replacing the evaporator to avoid debris in the new compressor?

It depends on if the compressor is self destructing or not. From what you've said, it sounds like your problem is the clutch. If that is the case, then you didn't contaminate the system and should be okay just replacing the clutch/compressor. If you have introduced metal or contamination into the system, then it should really be flushed, then evacuated and re-charged. If that is the case, the parts you really need to worry about are the new compressor, and the expansion valve or orifice tube, and the drier or accumulator if it has a filter in it. The evaporator, condenser, and hoses will get cleaned during flushing and will be fine.
Is it cooling when the clutch is engaged? If so, I would just replace the compressor, evac and re-charge. If you can conveniently flush it, then do that to just to be safe.

I will point out that in many cases the compressor supplier specifically states that if the drier is not replaced at the same time they will not warranty the compressor against failure.

I use these people a fair amount. Good quality stuff. Their warranty page: http://www.discountacparts.com/warranty.htm

From that page:

AC COMPRESSOR WARRANTY AGREEMENT – READ THOROUGHLY Failure to follow these 12 steps when installing the compressor will void your warranty.

1. MUST clean A/C system with an approved (R141b and Dura Flush are approved) flush, using an approved flushing method. If an approved flush is not available, an in line filter MUST be installed per the instructions included with the compressor.

2. MUST replace filter drier or accumulator.

3. MUST replace orifice tube or liquid line that contains orifice tube (if applicable).

1. Inspect/replace thermostatic expansion valve & clean inlet screen (if applicable).

2. Check for proper air flow through cooling fins of condenser & radiator (condenser may need to be replaced, see additional information in the instructions included with the compressor).

3. Check for proper fan clutch or electric fan operation.

4. Check compressor clutch air gap before installation (refer to OEM or compressor manufacturer’s specifications).

5. Must add correct type & amount of refrigerant oil (refer to OEM or compressor manufacturer’s specifications).

6. After hose assemblies are attached, turn compressor shaft (not just the clutch pulley) a minimum of 10 times to clear oil from compressor (a spanner wrench may be required).

7. Check compressor clutch electrical circuit for proper voltage (use either OEM or compressor manufacturer’s specifications).

8. Use only R12 or R134a refrigerant.

9. Evacuate entire A/C system for a minimum of 45 minutes if the temperature is above 80 degrees

(60 minutes for dual air system or if temperature is below 80 degrees).

Four Seasons compressor replacement instructions. On the second page, the first thing mentioned is replace the drier. http://4s.com/upload/Four%20Seasons/Documents/Comp_english.pdf Four Seasons requires a flush. http://www.4s.com/Upload/Four%20Seasons/documents/Tech%20Tips/English/4S%20324%20AC%20SYSTEM%20FLUSHING.PDF

In many cases, you must have a reciver drier charged out on the same invoice as the compressor in order to get warranty coverage. Some companies will allow the purchase of a drier elsewhere, but the invoice must be presented when you apply for warranty on that compressor.

A good way to tell if the compressor was beginning to die is to look at the color of the oil that comes out of the system. Much like the engine in the car if there is metal flake in the oil, it's on it's way out. All of the exploded ones I have replaced had dark grey metallic oil in them, the healthy ones had the UV green or whatever color had been put in there by the last service.

A cheap ford dealer approved (about 10 years ago anyway) way to flush out the lines is rubbing alcohol and compressed air until it comes out clear.

I'd always replace the drier as cheap insurance they're under $20. I have read that you can force the water out of the desiccant by heating them for several hours (yay thrift store toaster oven in the garage) and that seems like good science. However heating will not remove any chunks ó metal or other crap in there.

Personally if I bother to evacuate an A/C system to fix anything I replace every O-ring I can get to if they are over a couple years old.