I have a black 90 245 that was purchased about 8 months ago from a guy in San Diego who didn't know what he had and how easy it was to fix all the problems. All the problems, that is, except the AC.

He had a local Napa shop convert it to R134 and replace the compressor. From what I can see, they were obviously not Volvo experts. It does not appear that they put in a new dryer nor changed any of the hoses (still said "Made in West Germany"). It sort of cooled occasionally.

As it was getting warmer here in LA a few months ago, I checked up on the AC. We replaced the vacuum tank to make the vents work and I installed a pusher fan that kicks on whenever the compressor kicks on. I found a leaky valve on the high side just before the dryer. Unfortunately, this was a valve that I did not have an adapter for on my gauge manifold.

I took it to an AC shop I've been using for a while and they replaced the valve and checked the system. I asked if we should be usig R134 barrier hoses rather than the old R12 hoses (due to the size of the 134 molecule) and they said not to worry about it. Topped it off and it blew cold. We drove it on a trip the next day and made it 80 miles at freeway speed before it died and only blew warm. Later in the drive (50 miles later), it started blowing coolish again. I took it back and they checked it again -- they said the aftermarket service valve on the back of the compressor was slightly loose and the 134 escaped, but it was only down about 7-8 oz.

A few days ago, it stopped blowing cold at a stop light and didn't cool again. A few hours later, it blew cold.

Today, I took it out in 78 degree weather and it was coldish for a few errands around town. I stopped at a stop light on the way back and it stopped blowing cold. No more cold after the next errand or the 5 mile trip home.

On my 86, I went through and did the full retrofit myself -- changing all 4 hoses, new rec/dryer, new evaporator (I had to change the blower motor, anyway), and added a pusher fan. Holy sheet, that sucker is cold -- even on a hot day I can't keep it on full blast for more than about 10 mins. On the 90, meh.

So on this 90, what should I look at next? The compressor and pusher fan are kicking on and I see fluid going through the sight glass on the rec/dryer. Could the low pressure switch have failed closed? Could my thermal switch have failed? (The thing with the tube down to the evap). I have not replaced the evap with the 134 version, which may be something I should consider, but I really don't want to dig into the dash. Suggestions? Thanks.