MB Enthusiast

1997 E320

Is the Duovalve and the heater valve the same thing if not where do I find the heater valve

ohlord

the 97 has a vacuum valve to control the same duo valve as in the later models,so it would be the same part just another item controlling it.
Since the a/c and heat are a full time demand based system the heater valve is the duo valve.
have your stuck?Diy rebuild on benzworld.org w210 section diy.
or sometimes a tap with the end of a screw driver handle on the sides of the valves frees them up.
ohlord

MB Enthusiast

I did some service on the Duovalve and I wanted to confirm this is where the leak was comming from since it was not visible when I looked at it.

My mechanic said I had a leak in my heater valve and my low coolent light came on.

I will do a more thorough inspection now that I know it is the same part

Thanks

I am in Florida - is it ok to top off with only water?

ohlord

with the dealer parts dept since it is the m104 engine,but if you have the dual zone climate control it should be the same unit as the 99 with the addition of that vacuum valve on the m104 that is not needed on the later models.
Autohausaz.com may list the two parts.
Always add 50/50 mix of zerex G05 the additives in it are what stops corrision and electrolysis in the aluminum block.How much is it leaking?
ohlord

MB Enthusiast

When the light first came on I was down about a quart

I have tighten the screws on the valve

They tightened slightly

Put in another quart and will check to see if it goes down again