A/C Troubleshooting Help

[dpatel710]

My a/c went from working well in the sweltering Florida heat to barely keeping the cabin cool on 80F days. 

 

First check of the low side was at 35 with ambient temps around 75F. A tad low but still within range on the gauge I have. Tried topping it off to 40psi and the vent temps actually jumped up a few degrees. 

 

VCDS shows no faults for hvac and measuring blocks show positive voltage, load, and rpm's for the compressor. 

 

The vents blow around 55F at LO with the outside temperature around 75F. 

 

While checking the low side pressure, I did notice that the condenser fan is not as loud as it used to be. It seems to be running on low vs. high where it sounds like a small aircraft taking off. Is there a low pressure switch/relay or is this a fan issue? 

 

Can anyone please offer some guidance? I haven't had to work on a/c systems too much so its something to learn for me. 

Thanks!

Edited May 27, 2018 by dpatel710

[AussieJet]

HVAC blower fan. The carbon brushes wear out over time. 

[Brett968]

OP, you might want to check out some of my posts on a similar issue I had with my car. Your symptoms match mine quite well. The problem was the compressor control valve (CCV):

 

 

 

[dpatel710]

Thanks Brett!

 

I did see your past posts and this is next on the troubleshooting list. 

 

I tried a deep vac and recharge by weight, replaced cabin filter, then replaced the condenser fan and relay. The car fooled me and the ac seemed to be working better after the fan replacement but it was just cooler weather at the time. 

 

Still no real improvement but I have noticed that the AC will randomly blow ice cold on long road trips - leads me to think its something going on with the compressor. When I did the recharge, at idle - low side 32, high at 150. Around 2k rpm, low was 40 and high at 170. High side pressure seemed low to me. 

[Brett968]

I also tried the deep vac and recharge with new drier. Then I repeated the same steps with a new expansion valve. No dice.

 

My car never blew cold, even on long road trips. Other than that my symptoms mimicked yours fairly closely. Your high side pressures seem low, and your low side pressures seem high. After I repaired the CCV, as I recall my low side pressures were around 20-25 psi tops. Low side pressures with variable displacement compressors tend to be lower than those of older clutched compressors--so you can disregard all those online pressure charts (which are targeted to old clutched compressors).

 

My high and low side pressures before I repaired the CCV were similar to what you are seeing.

[dpatel710]

Gotcha, I will try the CCV rather than a used compressor as my next step. Thank you for the help!!

[sponcar]

I just had a similar issue. It would blow slightly cold moving but stop working when sitting on traffic. It end up being my compressor. If you have access to a/c gauges, I would like to see what readings of pressure you get on both (Low and high pressure ports).

 

[dpatel710]

I replaced the compressor and dryer, all is well now. Before replacement - low side was around 35, high 150. After replacement - low 30, high 175. 

[Brett968]

On 7/25/2018 at 10:28 PM, dpatel710 said:

I replaced the compressor and dryer, all is well now. Before replacement - low side was around 35, high 150. After replacement - low 30, high 175. 

Did you try replacing the CCV first (which, of course, is a part of the compressor)? Just curious...

[dpatel710]

30 minutes ago, Brett968 said:

Did you try replacing the CCV first (which, of course, is a part of the compressor)? Just curious...

 

I was unable to find the correct CCV without ordering trough gogal directly so I opted for compressor replacement. Picked up a used one off an 06 CS. 

Edited July 27, 2018 by dpatel710

[Brett968]

6 minutes ago, dpatel710 said:

 

I was unable to find the correct CCV without ordering trough gogal directly so I opted for compressor replacement. Picked up a used one off an 06 CS. 

Gotcha. I see now that the Gogal-branded CCV is not available from Amazon anymore. Bummer!

 

For people that may read this thread in the future, Polar Bear, Inc. should have the correct valve available--albeit for a few dollars more than the Gogal. The trick is getting the right one. It looks a lot like their EX 007 but you will need to verify! Currently selling for $62.79 with free shipping.