Air Conditioning - 97 850

[Barry]

My air conditioning was not working this past spring. I took the car to an AC specialist. They checked for leaks and could not find it. So they pumped in more freon and added dye for a dye test. That was the end of June. The AC has been working fine all summer, every day! I have gone back to have them check for the leak by finding the dye - they could not find anything. They suggest that by next summer, all the freon could be out and I could be back at the diagnosis stage all over again.

[babynate]

They may have black-lighted the system to check for leaks once they put dye into it, but did they check the evaporator. The most common problem with the 850's are typically the compressor and the evaporator. You can get to the compressor with not too much problem, but the evaporator is behind the dash on the passenger side and you can't see if there are pinholes in the evaporator without removing the dash. I had the same problem with my 850 where the compressor went bad about 3 years ago (had it replaced) and the evaporator went bad this past year. You are fortunate that a charge will work, although the problem will get worse over time because the holes in the evaporator will get larger and the repair typically costs anywhere from $850-900 non-dealer on up to $1400 at a dealer. I have a place that will do mine in Ohio for around $850 and they are very reputable (the name of the place is the Volvo Shop and all they work on is Volvos there number is 330-297-1297).

I think you might be able to nurse the evaporator along for a while by... first trying just a recharge, if that doesn't work next try a recharge with some sealant and then finally try an entire can of sealant and then doing the R-134a charge. You can charge this thing yourself for about $20 bucks by getting 2 cans of R-134a with oil and sealant from Walmart. The system takes 1.6lbs so you would want the cans with around 12 ounces of sealant each. If this doesn't work you might want to go the route of getting an entire can of sealant (you can get something like Super Seal Pro from Autozone or others) and then charge with the R-134a. The way the sealant works is by staying vapor until it hits oxygen, once it hits oxygen it comes out the pinholes, coagulates and closes the hole(s). If the hole(s) are to big you will need a new evaporator, but you might want to try these first. I've heard contrasting opinions on whether or not putting a vapor based sealent into you system would harm other components in the AC system, but most of these are just opinions and I haven't read any posts anywhere from people with damaged systems other than opinions. The point is to me that I have a car worth about 4-5 thousand dollars on the open market and possibly $2500 as a trade. I'm not about to expend $1000 on the AC system in order to cool for 3 months out of the year. I personally would deal with the inconvenience for a few years before giving the car up and at best try all of my charging options. Everybody needs to make that choice for themself based on the value of their car.

One final note: The spot for filling the R-134a coolant is on the top of the engine compartment and on the passenger side about 1 foot from the front window. I think it even says R-134a on it. You can't miss it... and it's easy to do. Good luck.

[matthew1]

Moving this post to the top -- it's loaded with great ac info.