B7 RS4 evaporator temperature high

[Drivebyracing]

Hi guys, struggling a bit with the ac, not long had the car, long story short it had had three compressors in the last 2 years with previous owner. It then blew the 4th up on me a week after owning it. The system was full of swarf and the orifice filter was blocked solid. I have cleaned out the lines, replaced the compressor, condenser, pressure sensor, drier and the filter. The system now works and has no faults, I have also reopened the filter to check for any remaining swarf to which there is none.

My problem now is although the system works it doesn’t seem cold enough, even though the pressures are good, the gas and oil quantities are good, the pipes get cold an condense, fan runs etc etc. Pop on VCDS and my evaporator temp is 8-10 degrees. My understanding is it should be more 2-3 degrees.

Can anyone shed any light on the situation as I’m getting a bit stumped now.

Also this doesn’t matter whether it’s on auto (climate control) or at a set temp

Thanks

 

[gary3306]

First thing that springs to mind for me is the quantity of refrigerant that's in there (enough in to bring the pump in, but not enough for efficient cooling). If it HAS got the correct quantity in, maybe there is still moisture within the system. When replacing parts I always vacuum down for a good hour prior to filling to boil off all moisture. If there is moisture there it starts to freeze in the orifice tube and plug the hole, resulting in warm(er) air. The warm air then melts the ice plug and the system goes cold again for a short time until the moisture freezes the hole up again, and so it continues. Also check the carbon filter/pollen filter in the car and check it isn't choked up. Other than that it is a bit of a puzzler because its a fairly simple system.

 

[Drivebyracing]

First thing that springs to mind for me is the quantity of refrigerant that's in there (enough in to bring the pump in, but not enough for efficient cooling). If it HAS got the correct quantity in, maybe there is still moisture within the system. When replacing parts I always vacuum down for a good hour prior to filling to boil off all moisture. If there is moisture there it starts to freeze in the orifice tube and plug the hole, resulting in warm(er) air. The warm air then melts the ice plug and the system goes cold again for a short time until the moisture freezes the hole up again, and so it continues. Also check the carbon filter/pollen filter in the car and check it isn't choked up. Other than that it is a bit of a puzzler because its a fairly simple system.

Hi Gary, cheers for the reply. Still pickling me now. I’ve forgotten to add I’ve removed the gas 2-3 times since to check the amount of refrigerant and to re check the orifice tube. Both the tube and refrigerant quantity were spot on so I am at a complete loss. Pollen has been changed also. The only two things I can think is the interior air temp sensor faulty in the climate unit itself. Or a faulty evaporator temp sensor? But both read a temp and alter. It’s. It like they register open circuit codes or read -40 etc. Really getting to me now to be fair

 

[gary3306]

Is the hot/cold control operating correctly?

 

[Drivebyracing]

Is the hot/cold control operating correctly?

Yep, works fine, hot to cold. It’s just like it’s a few degrees out as you get to the colder temperatures

 

[Nightingale]

Have you ever figured out the cause of the problems? My fourth AC compressor just made a hole in intself also. We already changed 3 times the dryer, condensator, compressor, high pressure switch, cleaned and vacuumed the system, etc. The last compressor worked since July 2020, the longest until now. The difference from the last service is that we also changed the evaporator, which was not changed before. What the hell is causing this?

 

[Drivebyracing]

Have you ever figured out the cause of the problems? My fourth AC compressor just made a hole in intself also. We already changed 3 times the dryer, condensator, compressor, high pressure switch, cleaned and vacuumed the system, etc. The last compressor worked since July 2020, the longest until now. The difference from the last service is that we also changed the evaporator, which was not changed before. What the hell is causing this?

It was the orifice filter causing the compressor failures. I knew this soon as the new compressor blew a week after owning the car. Most garages overlook it. It worked after changing it. Just never quite seemed cold enough to me. I have sold the car now mind . But yes, deffo this filter will be your cause, catches all the swarf from your first failure and if not changed puts the pressures to high and blows the next. Hope this helps. You should be able to see in the pictures where it is, Offside scuttle area need to split the pipe on the nut shown

 

[Drivebyracing]

It was the orifice filter causing the compressor failures. I knew this soon as the new compressor blew a week after owning the car. Most garages overlook it. It worked after changing it. Just never quite seemed cold enough to me. I have sold the car now mind . But yes, deffo this filter will be your cause, catches all the swarf from your first failure and if not changed puts the pressures to high and blows the next. Hope this helps. You should be able to see in the pictures where it is, Offside scuttle area need to split the pipe on the nut shown

Was a fun first job after owning the car a week nice bill too and that was me doing the work as well! Hate to think if I paid someone to do it!

 

[Nightingale]

We always changed that filter. That's why we are out of ideas really, all components were changed I believe, with the exception of hoses.

 

[Drivebyracing]

We always changed that filter. That's why we are out of ideas really, all components were changed I believe, with the exception of hoses.

Oh right, hmmm, I’m not sure then sorry. I’m guessing you aren’t getting any swarf in the system? I blew my hoses out with compressed air. I can’t imagine a hose being the issue but have seen power steering high pressure lines collapse internally so suppose anything possible. Sorry can’t help anymore