Ibyellow

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

BOTUS

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

clb0099

if you need the valve I have brand new one for sale.

Pierregirard

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.

Ibyellow

Sorry I didn't get back to you sooner.
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.

BOTUS

the valve cost $500


its heading to winter already UK gets 3 nice days a year (in a good year)