coolant leak

Beside my 2007 Sprinter I own a 2008 Jeep Grand Cherokee with the same OM642 engine as the sprinter. (almost the same..)

Was driving the Jeep a couple of days ago just a short distance to the store and noticed the AC was loosing efficiency and when checked the water temperature - it was going to the red.
Opened the heating (lowered the engine temperature) and drove it back home.

Not sure how wise was that decision yet...

Back at home I topped up the coolant and noticed that it is rapidly going out somewhere.

Pressure testing the cold system showed that I cannot pressurize it at all and I can hear air escaping somewhere on the top front of the V.
Checked the hoses - none are leaking. The coolant is running down on the back of the engine and originating in the top front of the V.

What could that be? Cracked intake manifold? Oil cooler? EGR cooler?

I started up the engine when I had the coolant filled up and it was working.

My first guesses would be the crossover O-ring on the intake manifold, oil cooler, then manifold.

Have you had any work done on your engine recently?

SSMaui said:

My first guesses would be the crossover O-ring on the intake manifold, oil cooler, then manifold.

Have you had any work done on your engine recently?

Click to expand...

Well, yes ...
Last year late October the oil cooler seals were done. All the seals were replaced including that crossover assy. To save my bad back, my brother in law who is a mechanic did the job in exchange for a plane ticket.
The only thing I can think of is if he over torqued something and it cracked now in the hot weather.
Not looking forward to this ...
My guess is the manifolds ...

was dealing with some health issues lately and I just started to work on it again.
Looks like the coolant is leaking from under the driver side intake manifold or the intake manifold is cracked. i have not removed it yet, so I'm not sure ...
Were there some problems like this?

Oh...your engine has the EGR cooler under there, too. (OR at least other versions of the OM642 for sedans and SUV does). The O-ring (fig. 20) and gasket (fig. 18) can leak coolant.

You gotta remove the manifolds to access though. Humbug...

SSMaui said:

Oh...your engine has the EGR cooler under there, too. (OR at least other versions of the OM642 for sedans and SUV does). The O-ring (fig. 20) and gasket (fig. 18) can leak coolant.

You gotta remove the manifolds to access though. Humbug...

Click to expand...

Absolutely right!
I was not sure what I am looking at first, but that is where it is leaking from #20 oring.
Thanks!


Have another question.
What is the proper way to disconnect this?

The leak line connection?

The outside "ring" looking thing pulls them straight up to unlock it from the injector. They're a PITA sometimes. I try not to use tools to pry them up. Even pressure all the way around is the key.

finally got it out. The oring is damaged.
Is there a mercedes part number for this oring?
never mind, found it