V70 - Air Con trips off in hot weather

[skids]

"it should run at a lower speed when ever the AC is on and working..."

The radiator fan is running with or without the air con being switched on, which is unexpected.

[skids]

An Update:

I have had the air con system re-gassed but the problem remains. The garage that conducted the re-gassing reported that the air con system still had an amount of gas and passed the check for leaks by holding a vacuum. They also confirmed that they had re-gassed the car two years previously.

However, while the gas refill initially appeared to solve the problem the system started cutting out after ten or so miles into a long drive.

Does anyone know what sensors, if any, monitor the system when running as I wonder if a faulty sensor is causing the problem? If there are none then I suspect that the electro-mechanical compressor clutch is the culprit.

Any thoughts?

[Clan]

Originally Posted by skids

An Update:

I have had the air con system re-gassed but the problem remains. The garage that conducted the re-gassing reported that the air con system still had an amount of gas and passed the check for leaks by holding a vacuum. They also confirmed that they had re-gassed the car two years previously.

However, while the gas refill initially appeared to solve the problem the system started cutting out after ten or so miles into a long drive.

Does anyone know what sensors, if any, monitor the system when running as I wonder if a faulty sensor is causing the problem? If there are none then I suspect that the electro-mechanical compressor clutch is the culprit.

Any thoughts?

Firstly the vacuum test has not been recognised since 2010 it is not reliable as it can "suck the crack closed" and not register a leak.

Did they put the correct amount of gas in? Over filling or under filling will result in loss of cooling power. There is a label under the bonnet to state this volume.

Since 2010 the correct legal way to check for leaks is to pressurise the system to operating pressure with Oxygen-free Nitrogen and see if the pressure drops over a certain time AND soapy water must be sprayed around joints and the condenser which will bubble up into a white froth if there is a leak.

You say he wasn't sure how much gas was in there? He should have collected the remaining gas and measured it before doing the leak test and filling with the correct amount.

All people doing work on AC have to do a training course and be certified and registered since 2010, are you sure this guy is legitimate ? you can ask to see their certificate.

From what you say there is a leak somewhere...you cant go any further until you know for sure there are no leaks and that the correct amount of gas is in there... but that is the Qualified Certified AC engineers job.

Good Luck ..

[skids]

Thanks for your very clear reply. I have just googled for information about qualifications and certification in the UK and have found various NVQ. Are these the qualifications that you refer to?

Simon

[4x4]

Find an old school A/C technician who uses gauges and not a machine to diagnose your system. I had my A/C checked and filled by a local garage on their new 'very expensive' machine and was told all was good only to find the A/C wasn't working, the pressure sensor threw a code and the fan ran full when turned off. I had to use iCarsoft to delete the DCT before the fan would stop. I spoke to several A/C specialists and took it to a local Volvo indie and every one gave me a different diagnosis. I eventually found someone who is an A/C specialist who uses gauges, scales and years of experience to diagnose my compressor was seized. New compressor fitted, nitrogen tested, PAG oil added and R134a filled and it now works perfectly.

[Clan]

Originally Posted by skids

Thanks for your very clear reply. I have just googled for information about qualifications and certification in the UK and have found various NVQ. Are these the qualifications that you refer to?

Simon

City & Guilds Level 3 Mobile Air Conditioning Regulation R/501/2950
is mine, It is an "Automotive Technician Accreditation" qualification.

I daresay there are many unqualified ( Illegal ) people going around in vans with a bottle of gas.

It is illegal to purposely vent Refrigerant into the atmosphere. The maximum fine is £40,000...

[davebb]

also you can test the pressure of the gas with vida and other diag tools, and compere it to the out side temp,
Dave

[Clan]

Originally Posted by davebb

also you can test the pressure of the gas with vida and other diag tools, and compere it to the out side temp,
Dave

Very few volvos have a variable pressure sensor in the AC system they are mainly simple on/off switches which turn off the compressor to protect it when the pressure drops to a very low value .

[Georgeandkira]

Thanks Clan for the solid responses.

Air conditioning threads are torturous to read for the author has a problem, we all know how AC operates basically and many responders offer focused experiences.
After all that we can't draw a good 'road map' for a fix.

As mentioned, real (legal) AC service begins with evacuating the system of both gas and PAG oil. The gas is filtered and saved as is the carrier oil.
The machine used by AC techs is commonly called a "console" here in the States.
The console creates and holds a vacuum. After X minutes of detecting no leaks, you get the OK to refill the system.

I've wondered about the difference between + vs. - pressures used for leak detection....in a system which is positively pressurized 100% of the time.

Every console I've ever seen (with Snap-On being the walkaway favorite) is said to add leak detection dye and seal conditioner to the measured refill.

I gotta believe a name brand console has measuring gear equal in operation to gauges, however, the savvy a seasoned pro brings could make the difference.

Also, people mention the clutch clearance and adding bread bag clips as spacers / shims. I've seen lots of "red powder" (ground away clutch material?) on lots of cars and never have I read a plain "my AC clutch is worn out" thread.

Could the pressure detection switch itself be bad / weak? They're featured on parts websites often.

[davebb]

Originally Posted by Clan

Very few volvos have a variable pressure sensor in the AC system they are mainly simple on/off switches which turn off the compressor to protect it when the pressure drops to a very low value .

Mine is a 2002 S60 D5 if they have done away with this on newer ECU it is a shame
as it is very help full,
Dave