Buying a used older motorhome is not for the faint of heart. Things will break and more things will break. Right around the 10 year mark things really start to go wrong and the previous owner of our motorhome felt that for sure. Because I don’t have any certainty as far as when things were repaired I decided to do basically all of the routine maintenance at once.
Rewind back to when we bought the coach - the a/c compressor clutch was fried. This is the air conditioning system built into the dash that works when the big engine is running. I didn’t think much of it at the time but I made the dealer replace the compressor, evacuate and recharge the system. The system was fully charged when they pulled the compressor so I didn’t make them replace the drier or other stuff though I probably should have. The tests went well and we went on our way. Fast forward back to now, while I was running the big engine to test other maintenance I was doing I had the a/c on to exercise it and make sure it was still working. The coach was in high idle and running for about 20-30 minutes. I noticed on one of my trips from the engine to look at the gauges that the a/c wasn’t very cold anymore. Sure enough I looked at the condenser fan and it was stopped. Later on after things cooled down I ran the a/c without the engine running and the compressor fan was working.. Hmm.. odd. I let it go a few minutes and strangely it started to go slower, slower, slower, stop. A few seconds later I heard the circuit breaker pop. Sounds like a toasted motor to me.
As it turns out on these coaches an SCS Frigette system was used. This company went out of business. My first thought was to get a new motor and a helpful ForeForums member suggested I go through the pictures on ebay to try to match the motor up to what was for sale on there. I found a few but without dimensions how can you be sure? So I went to autozone. As the counter clerk and I perused random condenser fan motors he asked “Why don’t you just replace the whole thing? We have universal units”. Hmm.. I didn’t think of that. He pulled out a universal that was the same size as mine, same thickness and appeared to have the same mountings. When I got home it turns out the mountings aren’t precisely aligned but nothing a few heavy duty zip ties can’t solve - after all this isn’t a critical part. While getting the old unit out, 2 of the existing screws broke in half as they were seized into their joints so I didn’t have new mounting hardware anyway, plus the new fan came with zip ties as the recommended mounting method!
A couple cut connectors, soldered joints and electrical tape later and wow, their universal fans are serious business. The amount of air moving through there was quite a bit more than before. It was only $64 which was cheaper than the cheapest ebay motor alone and cheaper than the $175 or so new old stock from Foretravel. So I’m happy, as long as the cheap chinese part holds up anyway. Time will tell but I saved the receipt and box ;) If you get one of these make sure the blades are installed right for pusher and puller mode (read the manual). If the blades are on backwards it moves next to no air.
I won’t explain how the a/c system works entirely but basically you can understand the failure mode of the previous a/c compressor if you think about it. Nominal high side pressure is probably somewhere between 250 and 300psi. When the condenser fan stops working high side pressure rises very quickly until a high pressure side cutout switch is triggered probably around 400psi. Maybe more. Imagine driving 8 hours down the road with the a/c system sort of working so you continue using it. The system is sitting right at the cutoff pressure cycling the compressor on and off repeatedly. Each time the compressor starts the clutch has to catch against 400psi and a high revving engine speed. Do this long enough and boom, clutch fried. The foretravel system is very dumb. It has a high and low pressure switch and the compressor runs constantly I believe. There is no intelligence whatsoever so the system has no way to decide that something is wrong and give up use of the compressor. That combined with infrequent use causes a lot of failures of RV chassis a/c systems in general. Use the system often if you have it and make sure your outside fan is working.
Also changed the engine oil, filter and fuel filter in the generator, a PowerTech 12kw diesel. The generator is on a slide and it went pretty much like you’d hope - easily.
Last modified: 21 October, 2014
Created: 19 March, 2014