Duo valve change
Thread Starter
Newbie
Joined: May 2024
Posts: 13
Likes: 3
W221 S Class 320L CDi 2006
Duo valve change
The passenger rear (UK car) ac always blows hot so I'm going to change the duo valve.
Struggling to find a video of the w221 (found others) but wondered if anyone had a link with a video or instructions with pictures to help me out?
Cheers
Struggling to find a video of the w221 (found others) but wondered if anyone had a link with a video or instructions with pictures to help me out?
Cheers
MBWorld Fanatic!
Joined: Aug 2014
Posts: 5,322
Likes: 1,678
S500
the valve sits behind the front right wheel (inside the arch liner) very simple job, the hoses are ridiculously long and its all easily accessible - it costs a fortune unique to the w220 and w221 - you need three pipe clamps and 1 ltr of merc blue coolant - basically bleed the hoses as you refit - then just top up the expansion bottle
1hr leisurely job - you don't need instructions or a video
1hr leisurely job - you don't need instructions or a video
Last edited by BOTUS; May 24, 2024 at 04:19 AM.
Super Member
Joined: Jun 2012
Posts: 893
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From: New Jersey
‘16 Mercedes GLE450 amg,’15 Mercedes gla, coupe,’07 Mercedes w221,’12 Audi A
if you need the valve I have brand new one for sale.
Junior Member
Joined: Dec 2023
Posts: 50
Likes: 11
From: Paris
Mercedes-Benz Vision EQS
From what I've seen, the duo valve is usually near the firewall in the engine compartment. It controls the flow of hot coolant to the heater core in the passenger area. You might have to remove some parts, like the air intake, battery, or other nearby components, to get to the duo valve, depending on your car model.
Thread Starter
Newbie
Joined: May 2024
Posts: 13
Likes: 3
W221 S Class 320L CDi 2006
the valve sits behind the front right wheel (inside the arch liner) very simple job, the hoses are ridiculously long and its all easily accessible - it costs a fortune unique to the w220 and w221 - you need three pipe clamps and 1 ltr of merc blue coolant - basically bleed the hoses as you refit - then just top up the expansion bottle
1hr leisurely job - you don't need instructions or a video
1hr leisurely job - you don't need instructions or a video
Just wondered what you meant by it costs a fortune? Or was it auto correct lol.
Will change it as soon as I get some better weather in the UK. Not sure my coolant is blue though. I've being trying to find out which it should have but different car parts sites give different ones evem with my car registration.
