V70 Air Con: Odd A/C Problem

[theccentric]

Hello,

First off, my apologies if I am asking a question that has already been covered. I tried searching the forum but couldn't find anything relating specifically to what I am encountering, so thank you in advance for taking the time to read this. First the details:

Location: Bulgaria
Model: V70 2.5 TDi
Engine Type: D5252T
Year: 03/00
Mileage: ~156K

So a few weeks ago, as I was driving I noticed that the A/C was blowing, but not cold air. I turned it off and back on again, but nothing. I noticed that the car was perkier than usual when the A/C is on (no power loss) when I got going from the stoplight. When I hit the gas to pass someone, I felt the compressor kick in and it started blowing cold air right away.

Important Note - The car idles @ 780 RPM. Since I bought the car (Import from Italy with 229K KM) the RPM's have never budged when the compressor kicks in. I thought that maybe this is normal for a diesel?

The above mentioned problem would happen on occassion, but now it has become much more frequent and does not rectify itself very easily if at all, or does so for a very short amount of time.

I have noticed that one of two things occur immediately before the A/C stops blowing cold air -

1. Compressor just stops working
2. When compressor kicks in, the RPM's will jump from 760/780 to about 850, and then back down. At first, this takes about a second. Soon after that, it takes 2 or 3 seconds to return to normal. When this is occuring, I noticed that if I press on the gas pedal @ idle it takes a tremendous amount of time for the RPM's to return to normal from 2K to 780.... way longer than usual and sometimes it seems to hang between 1 / 1.5K


Today we were driving back from Greece on holiday, and the A/C didn't work properly for more than 5 minutes at a time for the duration of the 6 hour trip.

Two things that I have noticed so far which seem to have an effect on the appearance and frequency of this problem are:

1. Outside temperature (was very hot outside today, about 38 -40)
2. Seems to be less frequent @ high RPM's


A few weeks ago I had the A/C system tested for leaks and the freon topped off. Of course, the problem didn't occur while I was there and the system was working perfectly.

Does anyone have any ideas on this one? Thanks in advance for any advice.

[Bill_56]

If it's worse in hot weather then it could well be an excessive clutch air gap.

The clutch is operated by an electromagnet. In hot weather the coils heat up, leading to an increase in resistance and hence a decrease in current and flux. If the clutch gap is too wide, that can be the final straw that stops it engaging.

Watch the clutch very carefully, with the engine running and A/C at 'cold'. When it's working, you should see the clutch snapping & releasing, thus the compressor cyclying on/off several times a minute. If it is the clutch problem you may be able to see the clutch twitching, but failing to engage.

I tried several and whilst there may be some competent folks about, I have yet to meet an Air Con 'specialist' who has the slightest understanding of clutch problems, all they ever want to do is 're-gas'. In my experience, only a good vehicle service dept has the savvy for real probems. Best I found was a Renault dealer, but I've no reason to doubt Volvo dealers are good too.

[rogereld]

We had similar problems with the climate control on our 2001 V70. There are several threads about the air con compressor clutch gap, and many of the problems you describe sound the same as the ones we had. Two years ago, especially during hot weather, the air con would work for a while, and then give up. The interior fans would get louder and the temperature of air coming in was less cold so the fan blew faster. (This is with climate control. It may not do this with the more basic air con controls). Sometimes switching the air con off for 20 minutes would get it working again for a short time.

Our local Volvo main dealer and another air con specialist who looked at the car told us the only option was to replace the air con compressor. Last year, after reading posts on this forum about repairing the compressor clutch air gap, we found a local mechanic who was competent and experienced in repairing the compressor clutch.

My experience was that many "air con specialists" don't have sufficient knowledge or experience of the volvo compressor clutch and it took a while to find someone who convinced me he knew what he was talking about.

Repair was a lot cheaper than replacing the whole compressor, and the climate control has been working well for the past year since the repair was done.

[theccentric]

Ok, so it looks like quite a few people have the same opinion about the potential problem, so it is the first thing I will have checked out as long as I can indeed find a competent A/C service and repair specialist.

Many thanks to you both for providing feedback!