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Saturday, October 25, 2014

Doug's Domain

Doug Vetter, ATP/CFI

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June 21, 2005

Air Conditioning Repair

I've managed to avoid maintenance on my air conditioning system for as long as I've owned the car, but as they say, all good things eventually come to an end. After a string of hot and humid days here in New Jersey, courtesy of a Bermuda high that took up residence off the east coast, the high moved out rather suddenly one day last week and temperatures returned to normal. Fortunately, that's exactly when my air conditioner chose to go on holiday.

CondenserThis turned out to be an easy diagnosis. When I depressed the snowflake button on the climate control system to start up the compressor, I could hear the doors that direct air over the evaporator coil moving into position, and the fan speed picking up as usual, but the compressor didn't engage and, predictably, the exhaust air temperature remained the same.

I immediately figured the system was low on refrigerant. Why? Air conditioning compressors typically stop functioning if the system detects low refrigerant not only because the compressor would have to work much harder to achieve the pressure required for the system to operate, but because it's lubricated with oil contained within the system, and loss of lubrication due to a leak would doom the compressor almost immediately.

Unaware of how much longer the nice weather would last, I took the car to the dealer, only to learn that they were short staff and my mechanic would be out until the following Monday because he was in school taking a class on the new E90 engine. I tried to make an appointment, but learned that they were booked for the next two weeks. To make a long story short, my service rep and I negotiated a compromise -- I'd bring the car back the following Monday (4 days away) and if my mechanic agreed to look at it they'd take the car in. In the interim, I'd drive with the windows cracked and sunroof open.

Monday arrived and I stopped by a bit after the shop opened to see my mechanic, who quickly told me that he had absolutely no time that day. He told me that his "official" schedule was booked the next day as well, but said if I could bring it back bright and early (7:30) the following morning before the shop opened, he would take a look at it.

Less than 24 hours later, I arrived at the shop and we got to work. With the car up on the lift, my mechanic's skilled eye saw the problem in a few moments. The bottom of the condenser was wet with oil, and the cover that protects the bottom of the condenser from road debris was holding some oil as well. The cover itself, however, appeared intact. Luckily, the parts guys had a condenser in stock, so at this point all I had to do was take a big gulp and swallow the $460 price tag.

Removing the condenser requires removal of the same plastic cover that must be removed to replace the radiator, two bolts near the edges of that cover (you can see them with the cover installed), some covers on the underside of the bumper, the refrigerant lines, and, if you value your sanity, the two grills. Once disconnected, the unit must be pulled out from below the car, so it needs to be on a lift (or at least 3 feet off the ground) to perform this work.

It took my mechanic 15 minutes to diagnose the problem and check stock, and another solid hour and a half to do the swap, recharge the system, and do a short test drive. Book labor is, as usual, a ripoff, but it's not impossible to see an average mechanic taking the better part of two hours for the swap. I arrived at 7:30 and left with a fully operational air conditioning system at 10AM -- but not before I thanked my mechanic for going WELL out of his way to accommodate me.

Miscellaneous Questions

While hanging out waiting for the A/C system to recharge, I asked my mechanic a couple questions, the first of which had to deal with the sunroof. At one point I was futzing with the open/close button and managed to hit it twice in rapid succession when it was approaching the fully open stop. And stop it did. I had to pull the interior cover off and use the tool to roll the roof panel forward a couple inches, at which point the motor regained control. I then opened it completely again (one-touch and manually) and closed it. No problems.

I asked simply "is that normal?", and he said "yes". It's rare, but possible that if you start and stop the sunroof in quick succession (like stuttering on the button), the roof can get stuck. It has to do with the limit switches, which are, coincidentally, part of the motor assembly. And if you're wondering, if the switches do fail (mine had not), you'd need to replace the entire motor assembly.

That question prompted him to look more closely at the sunroof and the tracks that guide it. He said that the lube on mine had dried out and had collected more than its share of gunk, so he removed what he could in the limited time he had and told me to use some WD-40 or other solvent / lubricant to clean up the tops of the track, and then use q-tips to clean out and relube the inner portion of the tracks in which the cables ride. He cautioned me, however, to not use a lube that would dry to a gel, or that might cause more problems than it solves.

I was feeling lucky today, so I also asked, "how reliable are the starters in these cars"? He said that like transmissions, they're rarely replaced, and added that his shop has installed perhaps four starters in the past year. Pretty good odds, I'd say. Why did I ask that, you're wondering? No particular reason...my starter appears to be working fine. And that sound you hear in the distance is me knocking on wood.

Parts: $471, Labor: $304, Total $822. Mileage: 118445.