warm AC. pay for diagnostics or just replace compressor

ylwgto · Post by **ylwgto** » 18 Jun 2021, 16:29

Just took my '09 XC90 3.2 to the AC shop after AC started coming on very slowly and not blowing very cold. Was hoping all it needed was a refrigerant recharge. Turns out it was holding a charge, so i'll need to take it to a shop that can run scans to determine what the source of the issue is ($100 for time, probably).

I'm considering just skipping the diagnostic and throwing that $100 toward replacing the compressor, since it is probably a bad compressor or bad control module. This is an easy job I can tackle. Thoughts on skipping the diagnostic?

My local guy says $225 to evacuate refrigerant before removal and for recharge. Seems fair. I've found units on RockAuto for $250-$350. These are for UAC, GPD or Four Seasons compressors. Anyone have any experience with these units?

My current compressor is a Valeo, Volvo PN 31291802.

Any tricks or other issues I may not know about in terms of replacing this? From what I can tell its pretty simple:
-get system evacuated
-move everything in the way (air box, PS reservoir etc)
-slip serpentine off (I'll probably replace)
-replace 0 rings on lines etc
-bolt it back up
-get it recharged

Any advantage to replacing other pats of this system while at it?

Post by **SuperHerman** » 18 Jun 2021, 23:42

A/c expansion valve could be the culprit.

Your mileage listed is 120k, which is not that high (but high enough to exclude a defective unit from the factory)? Compressor failure is not common as the system has oil in it. What usually happens is the bearings fail (you should be hearing this) or the seals leak (you would see this - having dye oil added helps). If the seals leak too much oil this could seize up the compressor as it runs dry. Overall the a/c compressor is a pretty clever design.

Your local guy is rather expensive, but it is NY. A competent A/C shop should be able to figure out what is going on. Where ever you brought it doesn't impress me.

When I brought my BMW in for A/C issues the A/C shop did various tests using their gauges and could decipher everything needed. Once you understand the system, which I don't, the high low pressure readings tell the story. I had talked to my friend a home HVAC specialist and he explained what could be the issues. I repeated these possible issues and the shop addressed each one with their findings.

You can do some research on "a/c expansion valve".

Post by **Roger_850T** » 19 Jun 2021, 09:35

I've been hearing lately about a solenoid by the compressor that can fail. Symptoms seem to be that it can take a few minutes after startup before the air temperature goes cold. FCP sells the part. I understand it's not hard to replace, but you have to have a shop evacuate your AC and recover the refrigerant before you can open it up. Then replace the solenoid, and evacuate and recharge. Note: I'm not sure this is your issue yet, but something to be aware of.

Here's the part: https://www.fcpeuro.com/products/volvo- ... h-31305844

Good luck!

Roger

ylwgto · Post by **ylwgto** » 19 Jun 2021, 20:57

Thanks. Yes, I've also heard about the compressor control module (which is basically a solenoid).

My compressor is silent and not leaking. No refrigerant leaks in the system. So I'm leaning toward this control module as well as the root.

Given it is about $120 and new compressors are $250 is it not worth it to just replace an 120K compressor for $100 more?

I am curious if the dryer and expansion valves should also be done, as those are much more labor intensive than the compressor.

ylwgto · Post by **ylwgto** » 29 Jun 2021, 12:21

Took it to a Volvo indy. Ran diagnostic and found no climate control or engine codes. He says bad compressor and quoted $1500 to replace (using Volvo parts).

I'm going to do it myself. Thought about replacing just the solenoid, but if that is not it then I'd have to pay for refrigerant evac and charge twice. Just gonna do the whole compressor.

Anyone have any experience with aftermarket compressor brands?

GPD brand ($210):
https://www.rockauto.com/en/moreinfo.ph ... 8&jsn=1320

UAC brand ($210):
https://www.rockauto.com/en/moreinfo.ph ... 8&jsn=1321

Valeo brand ($275)
https://www.rockauto.com/en/moreinfo.ph ... 2&jsn=1322

Nissens brand ($310):
https://www.rockauto.com/en/moreinfo.ph ... 8&jsn=1323

Full lust here:
https://www.rockauto.com/en/catalog/vol ... essor,6628

Post by **jimmy57** » 29 Jun 2021, 13:08

The engine control module runs the compressor variable displacement solenoid. The climate control module monitors the evaporator temp sensor and requests compressor displacement level which is used to determine the duty cycle of the VD solenoid. Expansion valves are not giving trouble on these unless there is debris from compressor failing that foul the system. The compressor will rattle or growl if the compressor has failed. I question how they decided it was charged to acceptable level. The static pressure for the gas in system will be the same from about 25% to 100% charge. The charge level has a great bearing on the compressor being able to vary its displacement. The solenoid failure usually starts with poor cooling performance for several minutes but suddenly it cools fine once the compressor warms and the binding VD solenoid frees up. It gets worse and quits cooling after a period of the delayed cooling phenomena. I have stopped putting solenoids in as the age and miles can mean you are replacing the solenoid on a compressor that will have other issues within a year in many cases. The drier is integral with condenser and can be (and should be) serviced but you need to remove things for access to slid the cylindrical drier insert out of the vessel on side of condenser.

wanderdüne · Post by **wanderdüne** » 29 Jun 2021, 13:40

I would go for the Valeo compressor, like for like. Also, and I don't want to wish this on you, but while you're in there, you *might* want to perform the not-fun 150K/ 10 year accessory belt and idler/coupler service. It is included in this thread, and there are more DIY's out there as well:
https://www.swedespeed.com/threads/the- ... ly.599937/

ylwgto · Post by **ylwgto** » 29 Jun 2021, 14:19

jimmy57 wrote: ↑29 Jun 2021, 13:08 The engine control module runs the compressor variable displacement solenoid. The climate control module monitors the evaporator temp sensor and requests compressor displacement level which is used to determine the duty cycle of the VD solenoid. Expansion valves are not giving trouble on these unless there is debris from compressor failing that foul the system. The compressor will rattle or growl if the compressor has failed. I question how they decided it was charged to acceptable level. The static pressure for the gas in system will be the same from about 25% to 100% charge. The charge level has a great bearing on the compressor being able to vary its displacement. The solenoid failure usually starts with poor cooling performance for several minutes but suddenly it cools fine once the compressor warms and the binding VD solenoid frees up. It gets worse and quits cooling after a period of the delayed cooling phenomena. I have stopped putting solenoids in as the age and miles can mean you are replacing the solenoid on a compressor that will have other issues within a year in many cases. The drier is integral with condenser and can be (and should be) serviced but you need to remove things for access to slid the cylindrical drier insert out of the vessel on side of condenser.

Thanks for this.

-ECM and CCM both checked, no issues.
-Compressor is not making noises or "growling"
-the reputable AC shop tested for proper charge, told me it was properly charged. If static pressure is the same for a spectrum of charge percentage, what should be done to properly assess this (so I can ask)?
-There is no fluctuation in AC quality, it is just consistently blowing not-so-cold during all driving conditions

So where would you go from here? I'm only in $75 for a diagnostic fee so far. Reluctant to replace the dryer...took a look today and do not want to take the front of the car apart or replace the entire condesner as it is not leaking. Swapping in a condenser, if that is the issue, I can do but given what you said perhaps it is still not charged properly? Could a super clogged cabin filter cause this (have not checked that)

thanks

Post by **abscate** » 30 Jun 2021, 06:57

You can spare the drier replacement since you havent opened the system. On the P80 platform Volvo says if you keep the system open less than 24 hours, you can just vacuum it out without replacing drier....BUT...

inspect your drier for corrosion - they rust out on our cars in the Northeast. The P80 drier sits down low and can get really funky

Go VALEO or NISSENS on that compressor. If the car is in your long terms plans, go FCP for lifetime warranty.

Where are you in the City? I can bring my stuff down to Port Jeff and do the vacuuming/filling there. Evacuation of charge should be a 30 minute deal - tell them you will pay 1/2 hour labour or get stuffed. I have gotten mine evacuated for free at a chain.

ylwgto · Post by **ylwgto** » 30 Jun 2021, 10:08

@abscate, thanks for the offer...I really appreciate that. I am currently in CA (bought the car here) and will be driving it back to NY in August. Need AC for that!

I'll move forward with a compressor replacement and recharge

Pondering the serpentine service, but man that looks like a sh*t job. I did the timing belt/water pump on my old 2001 XC70 and this looks worse.

Thanks