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TOO MUCH OIL & TOO LITTLE R134

FJRIVAS on Wed November 04, 2009 10:39 AM User is offline

Year: 2006
Make: VW
Model: JETTA
Engine Size: 2.0T
Refrigerant Type: R134
Country of Origin: Dominican Republic

Folks,

Long story short... I've been having A/C issues with my car and I decided to have the VW dealer replace almost everything to restore the system to "new" like conditions. They replaced the compressor, condenser, dryer, evaporator and expansion valve.

To my surprise the AC system is not working properly, not like new for sure.

When the ambien temp is not too high, let's say 25 Deg C the system works pretty good... I can get a fresh air temperature of about 10 Deg C, not bad. However when the ambient temperature rises, let say to about 33 ~ 36 Deg C they system performs horribly, I mean fress air temperature of about 30 ~ 31 Deg C... simply not acceptable. They are now telling me that there is a high pressure switch defective which is cutting off the compressor.

I believe the automatic climate contro system is working fine... However I strongly believe they charge the system with excessive amount of oil and too little refrigerant. Is it poosible that too little refrigerant and too much oil can cause the system to behave this way?

Thanks for your help !

Francisco

Chick on Wed November 04, 2009 3:27 PM User is offlineView users profile

Not knowing how much of either is just guessing, you don't list pressures so we can't even help with that..bring it back and tell them your complaints and see that they fix it... It should not be shutting off due to the high pressure switch, but only pressures will tell you if it is..Make sure the fan(s) are plugged in and working also.. If you could ask them to write down the pressures when they work on it..

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Chick
Email: Chick

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Freedoms just another word for nothing left to lose

FJRIVAS on Thu November 05, 2009 2:56 PM User is offline

I understand what you say Chick... I just wanted to know if it is possible that a combination of too much oil and little refrigerant can cause the air conditioning system to behave this way. That is:

1. Cool under fresh ambien temp.
2. Not good at all under high ambient temp.

Thanks,

Francisco

iceman2555 on Thu November 05, 2009 6:15 PM User is offlineView users profile

Too much oil and too little refrigerant can effect cooling efficiency.

The system should have been flushed to remove all residual lubricants and to insure the proper amount of lube replacements and the condition of the lubricant. Failing this and then recharging lube to OE specs will effect all operations of the system.

Another issue could be the amount of refrigerant in the system, if the vehicle was recharged using cans instead of the proper recharge equipment the system could be 'undercharged' and this alone could result in the described condition. Another issue could the replacement TXV esp if it is an aftermarket valve. We have seen numerous system problems such as yours that were traced back to the TXV.

The post indicates that the evap and condenser were both replaced along with other pertinent parts...this is a very good approach for a successful AC repair. Considering this, why do you think too much lube is in the system?
Seems as if the refrigerant recharge issue would be the first consideration and the TXV second.

This system uses a variable swash plate compressor and these compressors are very charge sensitive. Charging with cans and to a specific pressure is not a good approach for proper operational system.

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The strongest reason for the people to retain the right to keep and bear arms is, as a last resort, to protect themselves against tyranny in government.
Thomas Jefferson

FJRIVAS on Fri November 06, 2009 7:27 AM User is offline

Thanks Iceman...

To answer your question, I believe there could be too much oil in the system because I know the compressor (Bought at the VW Dealership) came with a full charge of oil, that is about 140 ml but I also saw in the invoice that they charged me about 150 bucks for "Compressor Liquid/Oil".

Here is what the repair manual for this car says: "The quantity of refrigerant oil is in a replacement A/C Compressor and equals to the total capacity"

That being said, if they added compressor liquid/oil on top of the oil that came with the new compressor ( 140 Ml) then the system has too much oil I think. Also, if they were just playing safe and removed the new compressor oil and added new compressor liquid/oil (To make sure no moisture was added to the system) 150 bucks of oil sound to me like way too much, I need to ask them exactly how much oil they added to be completely sure.

Best regards,

Francisco

NickD on Fri November 06, 2009 8:09 AM User is offline

Another factor that greatly affects performance is the introduction of air into the system, that really skyrockets high side pressures and to keep them under control, a much lower charge has to be used. And air does not cool very well. But just speculation, only thing that is safe to assume, you have a rather incompetent service department.

Even around here, dealerships are the worse for AC repair, did have access to a very good extremely knowledgeable mom and pop shop. The guy was so knowledgeable and reasonable, wasn't even worth doing it myself. But he retired, so went back to that repair myself, ha, actually for the last 25 years.

That is also one solution, to learn and to do it yourself. My wife always thought her mechanic in Venezuela was excellent, but after I had seen his repair bills, she was getting nailed to the wall, and certainly wasn't very good at AC.

150 bucks for a few drops of oil? That also sounds like Venezuela, really don't have any suggestions as to how to deal with your mechanic, that you will have to figure out.

FJRIVAS on Fri November 06, 2009 9:05 AM User is offline

Thanks NickD, I actually got a pretty good laugh at some of your lines... Trust me I appreciate it as I was having a bad day just thinking about this thing.

The car has been 2 weeks at the VW delaership in the climate control ICU (Intensive Care Unit) and I have to agree with you... Very incompetent ! They said the car will be ready today, but even if it isn't I'll take it to a dedicated A/C shop. What bother's me the most is that the solution of this problem will come down to fundamentals:

- Proper amount of oil.
- Proper amount of R134.
- Good vacumm before charging to remove air and moisture.
- Etc...

I mean after all they are not building a rocket here, system should be like new since I put a new compressor, condenser, dryer, evaporator and TXV. Is it a high tech climate control system? Yes, but after all the automatic climate control (ACC) system only controls the compressor... the control module has no control over the condenser, tXV or evaporator and I know for a fact that it is commanding the compressor for max displacement. Therefore if it is not cooling is because of the oil/r134/air/moisture mixture that they put in the system. Let me take that back, I am not 100% sure if the systme is asking for max compressor displacement... I would need a osc scope for that since it doesn't use a clutch but a external control system which uses a 400 - 500 Hz PWM (Pulse Modulated Signal) ... After I measure that I'll be without doubt sure that the system is asking for max compressor displacement.

Sorry if I am writing too long but needed to vent some of the frustration.

Best regards and thanks for your comments !

Francisco

NickD on Sat November 07, 2009 7:06 AM User is offline

Regardless of how complex ATC is, can directly activate the clutch coil with a remote starter switch, have gauges attached, and completely bypass that system. Have to keep your eyes on the gauges and be ready to release the switch, but this let's you know if you system is mechanically sound. And with the doors open, engine running 1,500-2000 rpm, AC on and blower at max, system should not cycle, and you can read your gauges to tell you what is wrong. Good to get that out of the way.

What you don't do is sit in a coffee shop and guess it's this or that sensor, see a lot of guys do that.

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