A/C compressors, lines, leaks, incl. 134a conversion


Greetings Campers:
Well the season of air conditioning is upon here in Colorado. I'm dedicated to getting my A/C unit working in my 84' 118HP Westjetta. Before I go there I have some questions for the Westfalia community on different compressors. The original Sanden 508 is toasted and my research has found that you could replace it with a Sanden 510. There will be two inches(?)more R134a in the system but according to two fairly reliable sources, both in Texas, the SD 510 will add more cooling capacity without additional line pressure in the system. The Techs did say that it would pull a little more power from the engine. Any thought on this would be appreciated. Thanks, Steve
 
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Capt. Mike

Moderator
Freon capacity is measured in ounces, not inches. The newer compressor may pull a couple more inches of vacuum -- not a significant factor in the running A/C.

Compressors are fairly generic so a close fit & specs shouldn't be a major drawback. The change to 134a required an absolutely clean system with no traces of the original R12 or any of the original system oil. That's the big compatibility rub when changing over because seals, etc., could be contaminated beyond the ability of a routine vacuum and purge cleaning. Thus the recommendation that all seals be replaced, too. A shop purging, especially if done a couple of times, may be sufficient to change-over without breaking the system down. I'm assuming your shop is also checking hose condition and saturation and replacing the receiver-drier at the same time. Older hoses eventually become saturated with R12 & oil as part of their normal breakdown during their life span. Hoses aren't forever!
 

icarus

Moderator
A/C 134 conversion

Well warm weather is back. After converting my sytem to r-134 last year, an update.(see the threads in aftermarket A/C systems)

Checking out my system before a trans continental trip, I discovered that it was not getting very cold. I went back to the guy who did the work. We could find no evidence of a leak, but we had to put in 1.4lbs of r-134. (about half the normal charge) His best guess is porocity (sic) of hoses. He figures that in most cars need a recharge every four to five years. Given the age of the westy ('86) and the shear length of hoses, losing 50% is about normal. Since r-134 is cheap, putting a pound or two a year is better economics than changing out all the hoses.

I will watch it for the next few months and update later.

Icarus

P.S. Jeremy at Bellingham Auto Air, Bellingham, WA. He helped with the conversion and did today's test and charge for no charge. He said it was still under warrenty, but I think that was generous.
 
Greetings:
Okay, it’s already too hot here in Colorado for me and I’m about to rebuild my AC system on my 84’ Camper. I’ve scoured the Bentley section 87 but it lacks guidance on where one can find the expansion valve in the Westfalia. It is my understanding that you must replace it to get coverage on the warranty. Before ripping into the rear condenser/fan cabinet I’m hoping to hear if any of you have done this job?
Thanks, Steve
 

Capt. Mike

Moderator
Transferred to consolidate same topic.

Vanna Junior Member

My brother has his ac certification and is installing a new compressor (Sanden 508)R-12 in my '85 Westfalia. This is what I was told I needed 10 years ago by the VW shop however since the AC never really functioned well when it was new, I never replaced the compressor. Now after 30,000 miles on a VW Factory remanufactured engine (still 1.9L) and a new paint job, I've decided to go all the way and cool "Vanna-White" down. (We are not converting to R134) I was not able to find any diagrams in Capt. Mike's file for the AC. Am I overlooking it somewhere on this site?
Where is the Receiver/Dryer located? Should I be able to get the correct at any autoparts dealer, or do I need to go to VW or Bus Depot? Where are the most likely places to look for leaks? I recall having to add R12 often, so I assume I had leaks. The hoses that run from the compressor to the front of the van use radiator hose clamps, which don't seem to be a tight seal (if it needs to be?). Any suggestions on where to find new hoses or any other areas to be in tune to for possible problems/leaks?

icarus Super Member posted July 21, 2004 11:12 PM

Why on earth would you not convert to R-134? The price of one future re-charge more than pays for the conversion, espescialy since you are replacing the compressor anyway. The shear length of hoses and seals makes for a partial recharge every year. I have had to add one pound of 134 in mine in a year, 20k miles. See my posts on 134 conversion. I have just returned across the praires (today) 105.7f in Glasgow Mt. We could keep the cabin about 75f.

Just an opinion.

Icarus

Vanna Junior Member posted July 22, 2004 08:30 AM

Actually, I must correct my original statement, I talked with my brother and he is actually using a drop-in Flash 12 refrigerant. It is not controlled and not nearly as expensive as R12. He purchased 30lbs for $200 compared to $900 for R12.(compared to 134a at $59?) I didn't feel I could stand to lose 20% cooling capacity in converting to 134a since it has always been a stretch to cool Vanna even when new. Thanks for your input.
 

Capt. Mike

Moderator
The receiver/dryer is located in the LR fender well just forward of the wheel above the trailing arm. It is fairly generic so available from many sources, but I'd look for one with the same fittings and sight glass that faces to the side and outward.

See the PARTS & VENDORS forums for comments on Bus Depot and other vendors.

Leaks are a slow, pain-staking process and require either a dye-type freon or preferably, a 'freon sniffer' electronic device. Hoses that use radiator style clamps are acceptable. Usually they have a special barb fitting on the pipe end and the clamp has a placement prong to assure good location.

Freon type efficiency may be measureable but shouldn't be the deciding factor. The Vanagon Westy's s notorious A/C performance is mostaly a function of air distribution, not capacity.

Caution on many of the substitute freons. Some are highly flammable. Stick with 134b so that you can get service and top-off (which will be needed on a Vanagon every so often due to natural osmosis through the miles of hose and minor leaks/seal loss).
 

icarus

Moderator
It seems that my re-fill interval for r134 has gotten shorter in the years since I did the conversion. I put almost 2 lbs in, in march and now it is not blowing nearly as cold. We haven't been able to identify any real leaks anywhere. I was wondering with the age of the hoses that run to the condenser and back, if they have developed tiny porocity leaks along their lengh. I see no posts about changing (or sourcing) these hoses, which leads me to believe that nobody changes them. It sounds expensive and time consuming to do it, but with the price of R134 going up quite fast I would like to tighten up my system as best I can.
Any Ideas?

Icarus
 

Capt. Mike

Moderator
Took me a few days to get to my "source", source being anyone that knows more than I, which doesn't take much. In this case the lead tech at the specialty shop that does most of the high-end dealer sub-contract work.

A/C hoses -- the R134a takes a barrier hose; without it, R134a will leak through, though it will hold R12. Compounded by the higher pressures R124a runs. Barrier construction hose began to show up in the mid-late '80's. Since Vanagons where at the end of their production cycle, I'd guess few if any got the newer tech hoses.

The amount of leak through is also a function of the amount hose in the system and Vanagons have a lot. As my A/C guru said, "Oh, that's expensive!" I was afraid to ask how much so.

Not so much a leak question but he also pointed out compromises in using R12 condensors; I'll post something on that in the appropriate topic.
 

tgabbert

New member
i have an a/c hose fitting problem. the suction side hose coming from the rear of the compressor on my 85 westphalia 1.9 has developed a crack in the aluminum fitting that seats into the compressor. this is the 45 degree fitting that houses the valve for system check and fill. i have been told this hose no longer is available. this info comes from most of the internet vw parts suppliers. so i went to my local hydraulic/ac hose maker. they recommend a two part solution. a fitting to connect to the compressor-then a small piece of hose-then a fitting with the valve- a small piece of hose- then a compression fitting to the existing hose that is still in the van. this seemed fairly straight forward and logical. a friend recommended purchasing the identical fitting from a junk yard with enough hose to compression fit to the exisitng hose in the van. another logical soluition. any thoughts, experience,or recommendations?
 

urgeii

New member
The AC on my '91 Camper was not cooling. I took it to my mechanic thinking it would need the normal topping up with R12 due to slow seepage. After replacing the compressor, expansion valve and evaporater the system will not take the R12 recharge. It draws a good vacuum, and the compressor runs, but it will take only a pound of R12. Any suggestions about what could be preventing it from taking a full 3 pound charge? Thanks for your help.
 

Capt. Mike

Moderator
Insufficient information (Guideline #3). What are the actual gauge readings, both high & low, at idle and at 2,000 rpm? Is there any fluctuation? What do you see in the sight glass? What are the ambient & output temps?

I'm also a little confused -- your shop replaced all these system components and didn't return it fully charged and working?
 

icarus

Moderator
I agree with Capt Mike about not enough info, but I would also suggest that you read over all the posts regarding R134 conversion. If you have spent as much money as I suspect you have on the system so far, I strongly suggest converting to R134.

Icarus

Ps It is -4c in Nw Ontario today with the first real fall snow. No need to worry about a/c.
 

tsmith5041

New member
Reading your posts about R-134 leakage thru barrier hoses is interesting. I my old 83.5 Westie, I installed an AC system that I I had cannabilised from a wrecked 87 and converted over to 134. In short order, I blew a hose from the pressure. I took all the hoses back out & took them to an AC shop where I had learned of barrier hose. They rebuilt all my hoses for about $300 and after reinstalling, they held as tight as could be hoped for in a system that large. This is an expensive and labor intensive solution and as I have the same leakage in my 87(when it runs), I'm looking for an alternate solution. On a website, http://www.autoairandmore.com, I found they have a product called TEAC125, a stop leak for AC systems that they claim will seal the larger pores in the non-barrier AC hose. Does any one have any experience or knowledge of this product? If it deliveres, without causing new problems, it could be a real boon to us all with AC leaks.

[Mod. note: Link dead.]
 
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jerepowers

New member
Does anyone have any experience with a refrigerant called Johnsen's Freeze 12?

It is supposedly an EPA-approved alternative to R-12 (Freon 12) that doesn't require changing seals or anything else. The cost of a can is $15 delivered. A kit with three cans, hoses, converters, etc., is $55 delivered. It still needs to have a pro evacuate the existing system, but like many people, my '84 Westy with factory air conditioning needs the annual topping up, which costs me $150 a year.

Here is the URL for the company www.freeze12.com
 

Capt. Mike

Moderator
Whenever a Google search produces nothing but sales pitches and testimonials, I get suspicious. Especially when the manufacturer won't tell you the specs and other info. I finally found the following on a Volvo owner's tech board. Most European manufacturers use the same A/C vendors, so this should apply to VW's.

R134 versus Refrigerant Alternatives. [Editor] The R134 conversion debate seems to be over and it is widely accepted as an alternative to R12. Numerous other refrigerants are also approved by the EPA as having met safety and environmental criteria. Unfortunately, the EPA does not test these alternative refrigerants for compatibility with refrigerant oils, elastomers, and other components in your car's cooling system. Santech Industries, a major producer of air conditioning components, has done some tests and found R134 the only acceptable substitution product for most applications. See the link for more information in the "testing and reference" section: http://www.santech.com/

Volvo uses HNBR in its black and yellow o-rings (some earlier seals were blue neoprene). They also recommend the use of ester oil as the replacement lubricant in R12 to R134 conversions. After testing HNBR and ester oil, Santech rated the following fluids for compatibility with HNBR seals:

"Poor" compatibility: Freeze 12 (80% R134a and 20% R142b)

"Marginal" compatibility: FR-12 (Frig c: 59% R134a, 39% R124, 2% butane), RB-276 (Freezone:79% R134, 19% R142, 2% mineral oil)

Similar results came from the use of mineral oil instead of ester oil. "Poor" means seal swelling in excess of 40%; "marginal" between 16 and 40%. They note: "HNBR and Nitrile are used predominately in air conditioning systems worldwide and were not generally compatible with the alternate refrigerants." Some of the problems reported from material incompatibility include:

Seals swelling where they would no longer fit into the glands
Seals splitting open
Seals extruding between metal gland surfaces
Seals turning into a gum type material
Hoses leaking throughout the length of the hose
Hoses collapsing on the suction side due to softening
Refrigerant later fractionating and leaving behind debris, poor performance,and damaged systems
Conclusion: when you convert your Volvo from R12, use R134 and an ester oil. To improve performance, consider a variable orifice valve.
 

jerepowers

New member
Ok, so R134a it seems it must be.

I have a 1984 US Vanagon Westfalia with factory air. It seems the biggest hassle in conversion to R134a is to replace the O-rings. The receiver and the compressor oil appear pretty straight forward.

So, now, where are all the O-Rings? Again, the Bentley is less than helpful, showing just the 1986 and later version. But looking at the Bentley I am guessing there are two O-rings on the back of the compressor, one where the compressor metal line connects to a flexible line, two on the receiver, two on the condensor and two on the expansion valve. Are there any more? Are all of them the same part? (Bus Depot lists one O-ring for the low pressure side only.) If not, where do I get them? And, maybe this should be first, do all of these need to be replaced?

I need to do something because I only drive my Westy 2,000 miles a year and at $150 a year to top off the R12, it's getting to be a cost per mile issue right up there with gasoline.
 

icarus

Moderator
The "O" rings are everywhere a hose couples to a fitting. Condesor, evaperator, reciever/drier compressor etc. When yo flush the system you will have to take all these fittings apart anyway for a complete oil flush, so changing the "O" rings is no big deal.

I suggest that you look over my post about converting to r134. Flushing is not hard to do, but I strongly suggest getting a pro to do it.

Good luck, keep cool,

Icarus
 

jerepowers

New member
I answered my own question about the number of O rings on a 1984 Westy. There are eight. Two each on the evaporator, condensor, compressor and the drier.

I bought a conversion "kit" from eBay for $30. It came with O ring lubricant and about 50 O rings of various sizes and the new connectors needed for 134a. If you have the time and ability to keep them all straight, NAPA sells the individual O rings for 59 cents each. The new conversion nipples are about $15.

The only O rings that are little tough to get at are the two inside the rear AC cabinet. I was painting my Westy so this cabinet was coming out anyway. There really are only six bolts that hold this thing in, plus you need to remove the screws and covers over the AC discharge. Two bolts are in the back, two brown carriage bolts from the front and two carriage bolts from the vertical clothes cabinet.

The other thing you need are some pretty large open-ended wrenches. The two couplings at the back of compressor are 28 mm. That same size is used elsewhere. The smallest wrench I used was a 19mm.

The drier, which also needs replacing when converting, is in a place, it seems, to maximize rust. It wasn't difficult to get to, but the fittings took some persuasion.

My old R12 system had a slow leak and I was tired of paying $150 annually to recharge it. After taking the old O rings out I would be willing to bet that the O rings on the back of the compressor and the ones on the evaporator were where the leaks were. The came out in pieces.

After I did this incomplete, semi-conversion, the shop finished it by charging $105 in labor to thoroughly vacuum the system, added an oil charge and two pounds of R134A for a total of $154 plus tax in June 2006. Last year they charged $1 less to add a single pound of R12. At least for many years, I plan to just add a bit when I need it.
 

Capt. Mike

Moderator
That it was 114°F in the grocery store parking lot yesterday reminded me I had an interesting A/C failure in my Dodge diesel truck (Chat Room) last month. Symptom: No A/C. Clutch would engage, then trip quickly; stayed on for extended period of time once or twice, then die again; may or may not rengage after a period of time.

When I got home and put the gauges on, the A/C decided to work so at least I could get readings and I knew it wasn't charge related; everything was correct. Finally, it quit for good. My best A/C tech said sometimes that indicates clutch "gap." In the Dodge, that is controlled by spacers. If the gap is too large, the magnet can't engage the clutch. Too small and I guess the clutch doesn't disengage completely or slips. Since the Dodge uses a Nippondenso or Sankyo-style compressor like VW, and the clutch is pretty independent of the compressor anyway, I started some research. VW is very remiss in the Bentley not discussing the clutch. An electromagnet pulls the two halves together so they spin together and drive the compressor. If they don't engage, no A/C!

The Dodge shop manual shows the blow-up and 3 internal spacer washers. It describes adding/removing spacers to adjust the gap. A quick check of the MBenz manual, same thing. VW does not discuss or sell the spacers but a check of their fiche plate 41-40, shows a blow-up of the clutch with a group of "clutch parts". In the group are 3 spacers just like the Dodge & MBenz, but no individual part numbers. Apparently VW has chosen that worn clutches should be replaced with a new unit pre-set. Clutches aren't all that expensive compared to the labor to pull one apart and do the adjustment. In my case, US$93 was about ½ the price of a clutch, but that it was necessary shows that the clutch is now worn. My wife's MBenz blew an A/C clutch a couple years ago and it took the compressor with it. Her bearings were shot and scored the compressor shaft, but was there an underlying loss of adjustment before . . .? If you catch a clutch failure BEFORE it has a chance to damage or seize the compressor, you don't have to open the system and all that entails.

When doing V-belt services on your vehicle, check your A/C clutch and gap. The clutch should not wobble. Gap for MBenz is .5±.15mm; Dodge .41-.79mm. I'd assume the VW is in the same neck of the woods.
 
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