V70 Air Con: Not very cold

[kdst5]

I am still having problems with the air con on a 2000 V70 SE T5. Last Friday the outside air temp was 18C but even with the air con set to the lowest it was not very cold.

The compressor cycles on for 10 seconds on and then off for 45 seconds, which I know is the classic low on gas problem. However I have had it checked for leaks and refilled. Also if it is low on gas it would cycle on and off very quickly?

So I am think it might be one of the sensors. I think there are sensors in the evaporator (temp sensor), a high pressure sensor in the compressor and a low pressure sensor in accumulator, can anyone confirm this?

I was thinking I could bypass the pressure sensors just to see if than made the compressor stay on for longer. However I am not able to reach them. Do you have to take the bumper off to access them?

Does anyone have any ideas or a picture of where the sensors are and how to get to them?

Thanks

Karl

[Alec Dawe]

Not sure about the location of the sensors, but short compressor cycling on a fridge system can be a sign of a blocked or frozen expansion valve, this causes the compressor to cut on low suction pressure, then as the gas leaks past the obstruction, it starts up again as soon as the LP trip clears etc etc etc.

Don't by-pass the sensors, they are there to protect the comp from damage as well as control the system, which they are doing at present. Doesn't sound like a sensor problem, or they wouldn't be 'resetting' and starting the comp up again, sounds much more like a system fault.
Have the system pressure re-checked, even though you had it gassed, you could have a hole somewhere, or compressor seals gone, etc

[kdst5]

When the system was regassed it was also pressure checked so I do not think I have a leak but a fault somewhere else.

I was only going to try bypassing the sensors to prove what is wrong while it is on my drive, not to leave it like it.

If it is a blocked or frozen expansion valve then is there any test I can do myself to prove this?

Thanks

Karl

[simmo]

I would agree with alec, sounds like a system fault rather than a component fault. If any moisture was present or introduced when it was regassed then it would most certainly freeze at the expansion valve giving similar symptoms as mentioned earlier, in that the ice would melt, then refreeze etc...

When it was leak tested how was this done? was it pressure tested or did they just pull a vaccuum? If they carried out a full vaccuum / dehydrate then this should have done two things, firstly highlighted any leaks if the vaccuum was done for long enough approx 60 minutes? if it's not done for long enough it may not highlight the smaller leaks. Secondly whilst the system was under a vaccuum this would have removed any traces of moisture which is paramount in A/C systems.

[jimathan]

It could be very dangerous to bypass any of the sensors or controls for even a short period of time. If the expansion valve is frozen then you could burst your condenser or damage the compressor.
If you have/had a small escape of gas from the low pressure side, it will most likely have drawing in some air. This would increase the head pressure and introduce moisture. This in turn would freeze in the expansion valve. It would not work successfully again until the dryer has been changed, any leeks repaired, and the system evacuated properly, and then refilled with the correct blend of oil and gas.
Air con/fridge /freezer systems are one of the few things that are most definitely beyond the scope of most DIY enthusiasts and should be left to the professionals.

[$hed]

i had my v70 regased good friday cool for no more than 5 days kwik fit said it was regased and pressure tested
they regased again the following saturday and pressure tested again
warm again 5 days later
i regased it my self this saturday and leak sealer has now gone warm again cant find a leak anywhere looks like have to get a pro to look at my system

[kdst5]

Its been regassed by an independent and also kwik fit. After both times its just the same I.E. not very cold and clutch on about 10 seconds and then off for 45 seconds. It been like this for several months and with the summer coming really want to get it fixed.

So anyway I don't think I have a leak, do I take it to a main dealer and end up pay £££? Is there anything I can do to eliminate certain items myself?


Thanks

Karl

[jimathan]

I would find a good independent aircon specialist. And let them sort it.
jim

[captcaveman]

Originally Posted by jimathan

I would find a good independent aircon specialist. And let them sort it.
jim

I too am having problems with my aircon, I had mine regassed by a specialist he told me I had a very slight leak but he was unable to find it.
The reason I had it regassed is It is a flat rate of £45 + vat just to open the bonnet even though I knew I had a slight leak I was hoping the gas would last more then a few months, as it happens it lasted 3 days!!!
The valve was leaking so I was hoping it was from there.
Looking at the condensor I would say it is leaking there, he pressure tested it by filling the system with Nitrogen at 250 bar.
If you look at the condensor it appears to have a wet residue in the bottom right hand corner which looks to be like a wet oily substance.
I need to remove the front panel to have a proper look, is there anyway I can pressurise the system myself? that way I could use a leak detector and eliminate the problem once and for all.
The speicalist said he was willing to do the job but I am very reluctant to pay somebody £45+ vat per hour to do a job I am more then capable of doing myself.
I can buy a new condensor for £145 all I need to know is how to pressurise it after that once I have cracked the leak I will take it back to the specialist to recharge.
PS the specialist drives around in a rolls royce so maybe im in the wrong trade!!!!

[malc-c]

I too was having issues with the AC on my '99 V70. I found a local mobile mechanic who als specialised in AC repairs. He first did a re-charge but that still didn't work as the clutch gap was too large and wouldn't click back in after the first engaugement. In the end we ended up getting another compressor from a scrappy merchant, shimmed that to 0.5mm, and then he spent best part of a day swapping it over. He then added some sealant, lots of oil, and re-gassed, and its been fine ever since.

I still need to have the AC / ecu reset as I get the Ac lights flash when I first start the car, but the car is now like a freezer when its running so can't complain

I was lucky, the guy quoted me £80 to do the work as he figured it would take a couple of hours, but as the compressor on my car is fitted by 4 bolts fitted 90 degree to the camshafts rather than in parralel to them (as often seen in the how-to's) he had to remove a lot more of the car to drop it out. However he stuck to his word so with teh £30 I paid for the compressor the job cost me £110 - Bargin