A/C Expansion Valve Replacement
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Newbie
Joined: Nov 2019
Posts: 13
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From: North Palm Beach, FL
ML350
A/C Expansion Valve Replacement
My A/C was diaged as needing the expansion valve replaced. It doesn't appear to be a difficult job but not a DIY. Has any other ML350 (166) owners had this repair done at an independent shop and what was the cost if you don't mind me asking- thanks!
Member
Joined: Mar 2013
Posts: 92
Likes: 23
2021 E-350 Loaded
I am a HVAC professional, a TXV is NOT a DIY job.
A shop that specializes in A/C should be fine. A dirty messy 1 man shop I'd avoid.
NOTE: get a price from your dealer, you may be surprised when comparing prices to competition.
Generally a TXV replacement involves a new valve, new refrigerant dryer / receiver, o-rings, recovery, evacuation, and recharge.
A shop that specializes in A/C should be fine. A dirty messy 1 man shop I'd avoid.
NOTE: get a price from your dealer, you may be surprised when comparing prices to competition.
Generally a TXV replacement involves a new valve, new refrigerant dryer / receiver, o-rings, recovery, evacuation, and recharge.
Member
Joined: Mar 2013
Posts: 92
Likes: 23
2021 E-350 Loaded
That doesn't sound like a bad TXV.
Did they reclaim and weigh in the proper refrigerant charge?
I don't want to diagnose via forums but if a TXV is clogged or failed it doesn't start to work unless there is moisture in the system (freezes). I've seem them overfeed, start cooling fine then die or just be dead period.
Inexperienced techs will just add refrigerant without observing the high side.
The sad part is by replacing the TXV they'll likely inadvertently solve the issue because the aforementioned would have to be done regardless.
That being said, I strongly caution against going to Walmart and buying a can of refrigerant.
Finally, to answer you question of damage, without going into detail, it's very possible to damage the compressor if the refrigerant flow is improper.
Last edited by SmokinJoe; Sep 18, 2021 at 09:07 AM.
Out Of Control!!
Joined: Sep 2018
Posts: 14,714
Likes: 4,606
From: unbegrenzt
2017 GLE350 4MATIC
When does the a/c fail the 10% of the time? On hot start-up or running down the road at speed?
That doesn't sound like a bad TXV.
Did they reclaim and weigh in the proper refrigerant charge?
I don't want to diagnose via forums but if a TXV is clogged or failed it doesn't start to work unless there is moisture in the system (freezes). I've seem them overfeed, start cooling fine then die or just be dead period.
Inexperienced techs will just add refrigerant without observing the high side.
The sad part is by replacing the TXV they'll likely inadvertently solve the issue because the aforementioned would have to be done regardless.
That being said, I strongly caution against going to Walmart and buying a can of refrigerant.
Finally, to answer you question of damage, without going into detail, it's very possible to damage the compressor if the refrigerant flow is improper.
That doesn't sound like a bad TXV.
Did they reclaim and weigh in the proper refrigerant charge?
I don't want to diagnose via forums but if a TXV is clogged or failed it doesn't start to work unless there is moisture in the system (freezes). I've seem them overfeed, start cooling fine then die or just be dead period.
Inexperienced techs will just add refrigerant without observing the high side.
The sad part is by replacing the TXV they'll likely inadvertently solve the issue because the aforementioned would have to be done regardless.
That being said, I strongly caution against going to Walmart and buying a can of refrigerant.
Finally, to answer you question of damage, without going into detail, it's very possible to damage the compressor if the refrigerant flow is improper.
Member
Joined: Mar 2013
Posts: 92
Likes: 23
2021 E-350 Loaded
LOL, blowing up the compressor internally, wrong refrigerant, hurting yourself.
Most kits don't have the hi-side hose and gauge and if there is a restriction you'll be operating WAY over the design head pressure. Most folks (even some certified auto mechanics) wouldn't even know what they reading on the gauges even if they had a full set.
Expensive car, have a pro do it the way I suggested.
Most kits don't have the hi-side hose and gauge and if there is a restriction you'll be operating WAY over the design head pressure. Most folks (even some certified auto mechanics) wouldn't even know what they reading on the gauges even if they had a full set.
Expensive car, have a pro do it the way I suggested.
Last edited by SmokinJoe; Sep 18, 2021 at 10:33 AM.
Out Of Control!!
Joined: Sep 2018
Posts: 14,714
Likes: 4,606
From: unbegrenzt
2017 GLE350 4MATIC
LOL, blowing up the compressor internally, wrong refrigerant, hurting yourself.
Most kits don't have the hi-side hose and gauge and if there is a restriction you'll be operating WAY over the design head pressure. Most folks (even some certified auto mechanics) wouldn't even know what they reading on the gauges even if they had a full set.
Expensive car, have a pro do it the way I suggested.
Most kits don't have the hi-side hose and gauge and if there is a restriction you'll be operating WAY over the design head pressure. Most folks (even some certified auto mechanics) wouldn't even know what they reading on the gauges even if they had a full set.
Expensive car, have a pro do it the way I suggested.
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Member
Joined: Mar 2013
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2021 E-350 Loaded
Thanks @SmokinJoe . Are you an MB or auto tech?
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Out Of Control!!
Joined: Sep 2018
Posts: 14,714
Likes: 4,606
From: unbegrenzt
2017 GLE350 4MATIC
You're welcome. No, I'm an Unlimited certified HVAC & Refrigeration Mechanical Contractor, Master Electrician and instructor since 1973. Please heed my advise, I can't tell you how many people have messed up their cars by trying internet DIY. I had my neighbor put 5 cans of the wrong refrigerant in the a/c of his Catamaran. Cost him $1400 just to get back to square one, only to find his water cooled condenser coil was fouled.
