Diesel-King

Hi,
One year ago the MB dealer changed the oil cooler seals to the new purple viton ones, replacing the old orange seals on my R320 cdi.

Unfortunately oil has started leaking again through the lower left engine weep hole.
There is no oil dripping from the turbo air inlet so I am inclined to think the problem is again with the oil cooler seals.

But I have also read that the turbo also has an oil feed (through the turbo pedestal?)
How can I tell if it is the turbo oil feed seals without removing the turbo?

Thanks for your help.

kajtek1

Those engines also have weaker seals on oil filter housing.
With complexity of the engine, you might want to spend 10 bucks on snake camera that attaches to your android.

Diesel-King

Thanks for the tip but it's not leaking from the oil filter housing (front of the engine).

Has anyone had leak problems with the viton oil cooler seals?

Luke.Berger

Hi, i have same problem...did you fix it ?

Thanks for your help.

peter2772000

The newer purple seals handle the heat better, but are harder and don't seal as well. Heat is your enemy here.
If the seals are leaking, replace them and lose the belly pan and engine cover in order to mitigate under-hood temps.

kajtek1

I sold my 2008 car with OM642 engine, but I used it in 120F heat, while monitoring temperature on climatronic and most of the time it would stay at 80C, while dropping to 78C going downhill. Electric fan would go to high when I park the car with AC on.
Bare in mind, that MY had no DEF, but at 180k miles was not new neither.

Towmater

If you get a blanket you can lay on top of the engine and look straight down the center of the turbo from the top. You'll see the two torx bolts holding the turbo and if you shine a light beside them that will show you if its leaking from the pedestal.

Diesel-King

No, I still gave the leak although I changed to the purple seals.

Will try to see looking over the turbo if it leaks by the pedestal...will report back....

Luke.Berger

Okay. Thanks

Luke.Berger

Okay. Thanks

Luke.Berger

So did you find a problem?

Diesel-King

I used an android endoscope camera but could only notice that there is no oil around the front part of the oil cooler (front of engine).....could not see if the rear end of oil cooler had any spilled oil.

I guess I will not advance unless I start removing parts standing in the way....but I'm too lazy for that.

As I see it, oil is still leaking through the new viton oil cooler seals or the turbo pedestal oil seal....can not think of any other cause.

Towmater

So, did you look down by the torx and look at the pedestal?

Towmater

You can also put in some dye.

Diesel-King

No, not possible unless I remove the air intake and possibly other parts like the fuel filter....will do it when the car is serviced.

Yes will add some dye once I receive it from Ebay.

Luke.Berger

Did you find a problem or no ?

dhurley

722.9 bushing style front pumps often fail and will weep fluid through the bell housing and mimmick the oil cooler seal leak.

Diesel-King

Took of the bellhousing rubber plug and cleaned up all oil....glued a piece of rectangular rubber underneath the bell housing hole with some strong silicone to determine if the oil spill came from inside the bell housing and left the hole open......but no, the spill does not come from inside the bellhousing!! The spill must come from the left side weep hole...but I'm not 100% sure...still investigating...

houseofdiesel

Did the oil cooler get replaced at the time of the seals? They are known to warp and leak, not just the orings fail.

Mohammad C

I have had this happen to me on my 2013 S350 bluetec. The first time I used all original Mercedes parts and then about 5000 miles later the oil leak developed again so now I’m thinking that the oil cooler itself has a warped so I am going to replace the seals again along with a new oil cooler. there’s simply too much heat where the oil cooler is located and therefore it it it just doesn’t last. Best to change out the oil cooler the first time.

GoodByeHonda

Can you please do us a favor and check the oil cooler with straight edge when you remove it?
imo it is more likely that proper torque was not applied to the oil cooler (due to thread/ block contamination) than cooler warpage being the culprit.

Mohammad C

the torque for the oil cooler bolts was done with a torque wrench and based on the book. The first time doing the seals I bought a new oil cooler from the local MB dealer along with the seals but did not use it. When placing the new oil cooler on a flat surface it would wobble as did my old one. So I figured it was normal—although strange. I have seen a lot of chatter about oil coolers failing as well due to warpage.

GoodByeHonda

Interesting. The only thing I can think that would affect the torque would be not cleaning the block holes. Given a rather low torque required on those bolts, I can't imagine taking these bolts off the oil cooler in some specific order would make any difference.
ive heared of a suggestion however to heat up the new seals slightly just before installation but oil cooler seals leaking shortly after exchange is rather rare event.

B34chBum

If/when I do this job I will use a sealant along with the o-rings.
There's a non-hardening one I use to seal the camshaft seal uppers on the VW PD motor, for got the name/links to it.
It is brushed on from a small can - would be tempted to do all machined surface mating with the cooler.

kkarb

I hadd the same problem. W166, ML350. Replaced oilcooler and seals 1 year ago. Still dripped a bit engine oil in rear right side of engine. To me it was the pedestall / beam gasked leaked. Dripped down at right side off the bellhousing. I removed the turbo once again, and replaced the pedestall / beam seals. One under beam an one between beam and turbo. I used a iphone endoscope to locate te leak, it was hard to detect. Se my pictures, its from the right side off the turbo pedestall.