On the 08 GL320, oil appears to be leaking from the right side intercooler hose. It does not always leak but seems to do it mostly after long highway drives, and will notice a few drops of oil on the driveway under right front of the car. I pulled the hose off today and the hose looks fine, I do not see any splits. I have a main hose coming from the engine which connects to an adapter, which then connects to a small section of hose then to the intercooler. Looking at the EPC, I only see the main hose, I am not finding the shorter piece. I figured I would just go ahead and replace all the hoses but they are close to $250 each! Do not want to spend the money to replace it if this is not really where it is leaking. Anybody ever been thru this before?

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This is a known failure item, simply replace the hose. Had the same thing on my '08 E320. Not sure the reason, but it's always the right (passenger side) hose that fails in this manner. There is a hairline crack in your hose that isn't clearly visible upon inspection, but once pressurized by the turbocharger, will reveal itself and spit oil mist into the vicinity. Replacing the hose is a five minute job.

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Current fleet:
1998 E300 turbodiesel
2008 E320 bluetec - leaky oil cooler seals replaced
2012 S350 bluetec
2015 GL350 bluetec

Sold:
1996 Passat TDI
1997 E300 diesel

This is exactly the answer I was looking for. I will order the hose but in the EPC I do not see the smaller short section of hose from the adapter to the cooler. It looks to me like this is the one that is actually leaking but want to replace both.

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+1. Same issue with the passenger side hose on my 09 E320. I do not recall seeing a piece similar to the OP's last post. Perhaps the GL has different routing.

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2009 E320 Bluetec - 242k miles and a work in progress!

We have an 08 ML and it’s different than the 08 E class.

The E class has the spring clip fasteners at both ends.

ML has the spring clip on the engine end but they used band clamps at the inter cooler end. Not sure if the factory clamps were Oetiker and someone replaced with screw type but that’s what’s on the ML now.

We don’t have that little adapter, the hose just attaches directly to the intercooler.

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The OM 642/722.9 powered family
Still going strong
2014 ML350 Bluetec (wife's DD)
2013 E350 Bluetec (my DD)

both my kids cars went to junkyard in 2023
2008 ML320 CDI (Older son’s DD) fatal transmission failure, water soaked/fried rear SAM, numerous other issues, just too far gone to save (165k miles)
2008 E320 Bluetec (Younger son's DD) injector failed open and diluted oil with diesel, spun main bearings (240k miles)

1998 E300DT sold to TimFreeh
1987 300TD sold to vstech

Anyone know if this is a failure item on newer OM642's? My wife's 2012 ML350 Bluetec has a small oil leak coming from the right side of the car. Drips about two or three drops after sitting overnight. Oil level rarely drops at all after checking it twice weekly so it is a small leak. Not sure if it is the intercooler hose or the infamous oil cooler seals....been too cold and snowy to crawl around and look yet.

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2012 Mercedes ML350 Bluetec 91K (hers)
2005 Corvette 55K (fun car)
2002 VW Jetta TDI 231K (mine)
1998 Volvo S70 T5 Turbo 196K (kids)
1994 Ford F150 4WD 249K (firewood hauler)
1983 Mercedes 300D 376K (diesel commuter)

The om642 in my 2006 Jeep GC has the same setup with push in clips at throttle body and the resonator and then both ends of the intercooler are band clamps . I presume different vehicles have the different setup for reasons of access, my Jeeps fairly straightforward in that I just remove the grille and its all there in front of me.

You really have to open it up, clean up the existing mess, and see where it is coming from. With all the under panels you sometimes find oil dripping far away from the source. Could be the intercooler hose, oil cooler, or oil filter housing. All are common leak points.

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2009 E320 Bluetec - 242k miles and a work in progress!