C207/M272 - Radiator Blower Air Block (Vacuum box) ?

[Uky]

Gentlemen

Recently I came to realize that I have never seen the Blower air-block valve actually shut off the air when doing a cold start. The old C207 with M271 always initially blocked the air through the radiator in order to speed up the engine getting warm (I take it). The present 207 with the V6 M272 never. The vacuum box is A204 501 01 06/001 and it has two connections: One two pin connector that is obviously an indicator and an air tight connector to a vacuum hose that according to a spare parts catalog is listed as "Hose line to intake manifold". I have not been able to detect any signs of air leaks. The connector seal is tight with no signs of cracks. There are no DTC's, no "Check Engine". Either the conditions has not been met (no-snow winter with temperatures steadily above freezing point) or whatever the fault may be has not resulted in any DTC's.

Of course, I lifted the V6 top plastics in order to see if I could locate where the hose ended but I was not able to find it at all.

Questions:

1. What are the conditions under which the valve are supposed to close?
2. Where on the M272 Engine does the Hose Line ends?

 

[Uky]

Found out the following:

The "Kühlerjalousie" is supposed to be an option with the option code "2U1"
which my car does not have. The vacuum hose provides a continuous vacuum
and the valve is operated by the engine management box/software. (the two pin
connector) In order to be functional, the 2U1 code has to be added in VDOC
and SCN-coded using Xentry.

The strange thing is that there is no information as to why Mercedes have
fitted my C207 with the hardware and then not added the feature in the
option list (!) Doing so is considered as a "Giveaway" which is an unneccessary
cost.

Anyway, it will be interesting to turn on that software switch and see what happends...

 

[Uky]

Update: The radiator shutter is standard equipment on the E350CGI.
I went and had it checked the other day. Xentry ran a test sequence (5X activation in 2 second intervalls)
and everything worked, Vacuum pressure:OK, Pneumatic valve current: OK.

But: No one had been able to answer under what condition the shutter is supposed to activate...

(Found an Error code for left exhaust Nox catalyst thermal sensor: -40C (NTC open)
No EML light was triggered. I replaced the sensor myself: €150