The Cooler

Published on 1/30/2019

My son, who’s 4 years old, refers to the air conditioning as “the cooler”. It was broken, and he was complaining.

A long time ago I got the air conditioning system refurbished with new (modern) fittings to be able to fill it with legal refrigerant, as opposed to the old CFC-laden stuff from before. This was 3 years ago - I did it when I put the car back together again after it was at the paint shop. But this December it stopped delivering cool air, and the rev counter dropped less and less every time I engaged the compressor. There was no more pressure in the lines.

So I took it back to CoolCo, and John and his team had a look and delivered the bad news: Their test showed dye all over the pulley. For a moment I considered whether I can just take the compressor off myself and let them refurbish it (saving on labour costs), but ultimately I booked the car in for the repairs. A decision that I was happy with a few days later when they called to ask if they can keep the car for an extra day, that there was a problem.

In the shop!

Here’s how I understand it. The compressor has a mechanical seal around the pulley shaft, and this seal was of course leaking. And since it was a system from before the new type of refrigerant, they had to fit that old-style seal. This didn’t last the night, and when they tested the next morning for leaks, it was already mostly empty again. I’m not sure why a replacement seal didn’t work, but John did mention that these mechanical seals are really hard to get off without damaging the compressor itself. In this case, it appears that damage was to the housing of the compressor, and the housing is what part of the seal presses against with its o-ring. Perhaps it was scored with a pry-tool.

This is an example of the old type mechanical seal. The left side is locked to the shaft, and rotates with it. It has an o-ring on the inside, against the shaft. The right side is a highly polished part that remains stationary, against which the rotating part, um.. presses and rotates. This has an o-ring on the outside, which seals with the housing.

Fortunately they were able to source a more modern replacement housing that accommodated a modern version of the mechanical seal. This did the trick and I (thankfully) got the car back before the sweltering heat of the weekend, and the park-off on Sunday.

But here’s the funny thing - you might recall how I struggled with the one bolt that hold the compressor bracket to the block. I told them about this and they investigated this too. When they were done they gave me a bolt back (that they had removed and replaced) with its thread completely stripped.

The bolt they gave me back (top) compared to the bolt from the scrapyard that I fitted (bottom)

I’m not sure yet what went wrong when I was working down there. This bolt clearly is not the same bolt that I found at a scrapyard and had to put in there using locktite. Anyhow, I’m not going to lose sleep over it (Jason’s words), and I’m again very impressed by their work, turnaround time and final cost of repairs.