A/C compressor cycling every few seconds, now dead

[FireFox31]

Hello, I finally must repair the dead A/C in my 2000 V70. Back around 2009-2014, the A/C blew nice and cold, but the compressor would click every eight seconds. Each time it clicked, there would be a split second decrease in engine power. No shops were able to proactively fix this problem. Since 2014, the A/C has been totally dead. No clicks, no cold air.

What can I do to diagnose and repair this problem? What would have caused that clicking every eight seconds, combined with the decrease of engine power? Any links to repair posts or part numbers would be much appreciated. Thanks.

[abscate]

If it has sat since 2014 uncharged (to be determined) you will need a number of components replaced.

To do this work yourself, the first investment is about $250-300 of AC tools to pump down the system, check for leaks, charge correctly, then evaluate performance.

The cans with hoses from Walmart won't work here.

A good AC shop should be your next stop - there is nothing indicated outside of normal AC service in your description.

[FireFox31]

When I took the car to a dealership around 2012, they replaced the freon. They found nothing unusual during the process. However, the A/C performed the same before and after the change; the air came out cold but compressor still clicked every eight seconds. I feel that there is no leak of freon.

I think that the compressor was strained, having to cycle every eight seconds to do the same job as a healthy compressor. I think that short cycling ultimately burnt it out.

What can I do to test the compressor and its components if I work under the assumption that the freon is fully present and not leaking? Thanks.

[abscate]

The compressor normally cycles (the click and engine load is the clutch engaging and spinning the compressor to pump the Freon).

Can you describe the cycle more accurately? Does it click on after 8 seconds, then stay for 4 seconds, then cycle off - then repeat? That sounds about right for a cool New England Summer. The compressor won't go on for full 100% duty cycle unless its pretty hot out.

[erikv11]

... What would have caused that clicking every eight seconds, combined with the decrease of engine power? ...

Every 8 seconds is not normal, that's too frequent. A worn A/C clutch would do that, you can check the clutch gap.

[oragex]

I think 5-10 seconds is about normal. it also depends on the air vent speed inside the cabin
As for the a/c not cooling, as above, could be too much gap (this job is better done from underneath)

[erikv11]

Hmmmmm well I trust you guys but I also offer up that none of my 95-98 P80 cars cycle anywhere close to that frequently. Is the 99-00 system that different? Am I not paying enough attention?

[abscate]

It's highly dependent on heat load ( temp, dun, fan speed), so comparing cycle numbers will quickly turn into a heated debate. On the way back from the Cape the other day we were running about a 20% duty cycle with ambient of 80F internal setting of 70F, I had verified charge and good temp drop the weekend before since I hadn't serviced it since new evap in 2013.

That manifold and pump have sure paid me back in c. elegans , I vacuumed out SWMBO car and got her AC to 40F of freezing temp differential , as well as the Eurovan, all in one weekend.



AC kills me as we only need it in July August, but I take heat really poorly, so i do like it to work. At least in IA in the summer, you get your money's worth out of it!!

[FireFox31]

comparing cycle numbers will quickly turn into a HEATED debate.

Zing! Good one. You'll be here all week.

Thanks for all the replies! To clarify, I was driving in horrible, hot, and humid NJ while dealing with this problem.

To better describe the clicking:
With the A/C on, I would hear a click from near the front passenger's footwell and feel a slight decrease in engine power. I would not hear or feel anything which seemed like the clutch disengaging. Eight seconds later, the click and lag would happen again. The A/C would blow cold.

Unfortunately, now the A/C doesn't work at all. For years, it worked with the frequent clicks. For the most recent few years, it hasn't worked at all. No clicks, no lags.

Since you mentioned the compressor clutch and its gap, I will research that as a potential problem. Thanks for helping to point me in the right directions.

[abscate]

When the charge drops below a certain level, the safety switch inhibits the compressor from operating so you could just have a leak. A good AC shop can sniff to help you find this , but the bad news is it's probably the evaporator buried in the dash on your " bastard" P80 ( like mine)

The release of the AC clutch is more subtle than the engaging, but the cycling sounds about right as described.

You can measure the gap with feelers. Lots of posts here on the bread clip fix, that has been superseded by Volvo of Hawkeye to the zip,tie fix.