# vacuum controlled engine mount



## elester12 (Sep 2, 2005)

I posted this on another diesel site and figured I'd share over here as well. 

If anyone has issues with their vacuum controlled engine mounts please check your vacuum lines leading to both mounts. I was getting excessive vibrations and found the vacuum line leading to the left engine mount leaking. Replaced the line and all is good. Hope this helps someone down the road!!

The two mounts vac line are connected to a "T-connecter". I noticed a crack in that as well.


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## elester12 (Sep 2, 2005)

number 6 was cracked on mine.


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## F32Fleet (Jul 14, 2010)

What do these things do? 

Sent from my MB525 using Bimmer App


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## Penguin (Aug 31, 2003)

BMWTurboDzl said:


> What do these things do?
> 
> Sent from my MB525 using Bimmer App


They change stiffness to reduce engine vibration, depending upon conditions, something like this:

*Engine Mount Control DDE 4.0*

The controllable engine mounts are switched to "hard" or "soft" corresponding to operating conditions.
*Function*

The pressure converter connects the engine mounts to the vacuum supply by means of hoses. When activated by the DDE control unit, the pressure converter switches vacuum through to the engine mounts so that they switch to "soft".
The engine mounts are activated at:


Road speed < 60 km/h and
Engine speeds < a value which depends on the coolant temperature as follows:
Below -40 °C: 1200 rpm
From -40 °C to -10 °C: 1200 rpm to 1050 rpm
Above -10 °C: 1050


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## Flyingman (Sep 13, 2009)

Wow, first I've heard of these being used in our cars.

Is it unique for the Ds or also the gas engines?

Actually I see on line it has been used on many cars especially transaxle. Soft at idle and then stiffens when put to work. I like the concept. Wonder where they came up with that idea?


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## finnbmw (Jul 6, 2008)

Interesting. I wonder if the X5 has the same thing? I have to remember to ask my SA next time I'll bring it in for service.


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## Pasa-d (May 7, 2011)

Shortly after I got my car I found the hose going to my left engine mount was being pinched by the undertray. It would surely have worn through if I hadn't have found this.


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## elester12 (Sep 2, 2005)

finnbmw said:


> Interesting. I wonder if the X5 has the same thing? I have to remember to ask my SA next time I'll bring it in for service.


My x5 has it too. Most service advisors don't even know what the difference between dpf and def is.

See here. http://realoem.com/bmw/showparts.do?model=FF03&mospid=51164&btnr=22_0131&hg=22&fg=05


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## finnbmw (Jul 6, 2008)

Thanks for the info! How did you know that the line was leaking?


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