Auto Service World
Feature   April 2, 2002   by Andrew Ross

Special Report 2002: One Cool Sube: Subaru A/C Quirks

The air conditioning compressor died with a shriek, not a whimper, in the middle of a snow squall.While a member of the public at large might greet such an event with shrieks of their own, when you're...


The air conditioning compressor died with a shriek, not a whimper, in the middle of a snow squall.

While a member of the public at large might greet such an event with shrieks of their own, when you’re putting together an air conditioning supplement, it screams “Opportunity!”

It’s an opportunity to learn about what quirks await technicians and jobbers faced with such a repair, and to pass a few points along. It will also allow us an opportunity to try out a Four Seasons flushing system that Blue Streak-Hygrade Motor Products is currently developing.

A/C failures are a year-round affair these days, since they are often tied into the windshield defrost system. The Subaru’s system is like this and, therefore, I estimate that the air conditioning system is probably on more in the winter than the summer.

Called in on the expert side to perform the repair was Sean Devine, an air conditioning specialist and owner of Maxwell Auto in Mississauga, Ont., who would be ably assisted by technician John Wedley who spent many years as a Subaru dealer technician before joining Maxwell late last year. He knows Subaru, and it’s a good thing too.

It’s also a good thing both are very patient, as part of this exercise was to look at all the possible options for such a repair, something that under the time constraints of a customer job would not be possible.

The 1993 Subaru Legacy Turbo Wagon is a rare model produced by the Japanese company, and parts turned out to be an issue, but I’ll get to that in a bit. First things first.

1) After a quick function check of the compressor (Shriek! Yup, it’s seized all right!), the next step was to check the integrity of the system. Devine says that his preference for leak checking is the Yokogawa H 10 sniffer. He says it gives him reliable results, without false positives or false negatives. He has trusted units from the company for more than 10 years.

2) Wedley says that a prime place for leaks on Subaru is around this join on the condenser.

3) Leaks ruled out, the integrity of the refrigerant is checked out. R-12 as it turns out, without any contaminants including air 100%.

4) After evacuating the system we opened the system and had a look inside. It appeared to be clear of any debris at the end of the hose. Unlike some systems that break down over time, says Devine, when Subaru compressors seize they do so suddenly and completely, which minimizes the chance of debris in a system.

5) In opening up the system, Devine noticed that the drier was coated in oil residue and dirt. This is usually the sign of a leak from the system, but as Wedley explained, on all-wheel-drive Subarus, the drier is located close to the front differential’s dipstick and filler hole. So, he says, it often collects drips, which in turn collect the dirt. Not knowing this could lead to a misdiagnosis of a leaking drier. A good tip.

6) Even when the eyes say things look clean, it’s still a very good idea to flush just to be sure. The Four Seasons prototype system uses a canister charged with compressed air and a cleaning chemical which, while strong smelling, isn’t that offensive and dissipates quickly. The used fluid came out the color of weak tea, which is good. If it had come out dark brown or black, we would have repeated the process and considered inline filters and replacing other components that might be partially clogged.

7) A retrofit is required by law in Ontario. Amendments to provincial regulations in mid-2001 prohibit R-12 service, mandating the use of an alternative refrigerant. We opted to go the R-134a route and this kit from Blue Streak includes R-134a compatible seals, lubricant and fittings.

I mentioned at the outset that this breakdown provided the opportunity to look at some options, and here they are:

The first option we looked at was to get a replacement compressor, but lo and behold, this is not so simple. Remember that we’re talking about a rare model of Subaru here. It seems that the Calsonic compressor used as original equipment has been succeeded by another model with ports at the 12 o’clock position rather than 3 o’clock. Notably, both the original compressor and the substitute compressor are notoriously difficult to get in the aftermarket.

We did obtain a “best guess” compressor from Blue Streak and some hoses and brackets from both Subaru Canada and Subaru Mississauga. Their contributions were valuable in helping us understand just how complicated this job could get for the uninitiated. We would have liked to take this route, but it was starting to feel like forcing a square peg into a round hole so we moved on.

8) Another option is the complete kit from Subaru, which includes the hoses, brackets, fasteners, a compressor and assorted bits and pieces. The retail price of the kit is the better part of $800, so while it is the simplest in terms of a new-unit solution, it is unlikely to be the one a customer with a nine-year-old car would choose.

The third option, and the one chosen in the end, was to remanufacture the compressor. It is also the likely option if an aftermarket compressor in inventory can’t be found, which would have been the faster option, but for reasons of model rarity, was not forthcoming.

10) Or at least we thought it wasn’t. It turns out that David Woodlock, production manager at Spectra Premium Industries, had worked their hard-to-find compressor forecast in our favor and had one on the shelf.

Having a compressor in hand, the job was the typical affair from this point on. One note that should be emphasized in any compressor replacement is to be sure whether it came charged with lubricant or not. Some labels warning technicians to add lubricant are nearly identical to ones drawing their attention to the fact that the compressor is already charged with oil. Be sure, or you may end up with too much oil in a system and hurt the cooling efficiency or compressor, or too little in the system and hurt its reliability.

11) The final bolting together in a retrofit is unremarkable, but does require the installation of the R-134a retrofit-compatible seals. It is also advisable to coat the seals with a little lubricant before bolting everything together.

12) Even though Canadian jurisdictions don’t necessarily require the installation of R-134a fittings in a retrofit, it’s a good practice that can save everybody a lot of grief down the road.

13) Our service included a couple of new belts: the accessory drive belt, which was due, and the a/c belt–shown here–which was fried when the compressor seized. Such replacements should not be considered optional.

Air conditioning service is not complicated in theory, but as many technicians learn, we don’t live in a theoretical world and the unexpected can happen. Rare models will come into every bay this a/c season and technicians and their suppliers should be mindful that quirks may be hiding in unexpected places. Keeping assumptions to a minimum and taking a by-the-book approach on unfamiliar vehicles is always the best bet.


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