Best Of

Yesterday I decided to tackle changing my long-neglected glycol. Although I originally anticipated this to be a relatively straightforward procedure, the recent concerns about corrosion of the aluminum fittings prompted me to do a little inspection in advance of the actual fluid replacement.

I started by disconnecting a few hoses. When that didn't cause the system to turn to dust in my hands, I got a little bolder and kept going. Eventually I removed the hoses from every location at which they were clamped to an aluminum fitting. Here is what I found...

First, the connectors at the Alde itself were pristine, and--as far as I could peer down into them (not very)--there was no evidence of any corrosion or other damage extending into the boiler.

However, every fitting in the convector loop had some degree of greenish salt-like deposits between the rubber hose and the outside of the fitting, and these deposits were associated with corrosion on the outside of the fitting. Some fittings were worse than others--in places where the build-up was greater, it had started to distend the hose, resulting in those characteristic bulges discussed previously.

The good news was that in all cases the corrosion was superficial. The fittings were still solid and the inner surfaces remained clean and undamaged. Here are photos showing the outside and inside of the aluminum connector just downstream of the automatic air bleeder:





In most cases, the hoses themselves had crystals stuck loosely inside them. Since most of them were disconnected at this point anyway, I took them inside for a good scrubbing out with a soft toothbrush and a thorough rinse with hot water. Here's a typical example:

 

Before reassembling, I cleaned up the affected aluminum with hot water and a scrubby pad. This removed the bulk of the crystalline deposits on the outside of the fittings. Here are before and after pics of the convector under the passenger-side bench:





Reassembly was easy enough, and no leaks were evident after refilling the system. However, if you attempt this I strongly suggest noting which hose goes where. Careful attention to this detail will result in you only having to reassemble the system once.  ;-)

If you are interested in reading about the actual glycol replacement, I've posted the details of that job here.