OM617 manifold oil = broken valve guide - PeachParts Mercedes-Benz Forum

Stretch · #1 04-22-2010, 03:43 PM

Dear All,

I've been enjoying my self recently pulling my car to pieces and I've found the following (potentially) alarming amount of oil on the inlet manifold - well most of it seems to be coming from the inlet side.

I'm quite new to Diesels so I don't really know how to gauge this problem. Is it a sign of impending doom? Or should I just clean it up and carry on as usual?

The car in question is a 1981 W123 300D. It has just done 100k miles / 160k km (Probably true - well more or less - I've got a pretty complete service history). It is a European model - no turbo - no EGR thingy.

Note the pooled oil in the throats.

Exhaust manifold

Pooled oil in the inlet manifold

The underside of the inlet manifold

Oil sitting on the gasket

I know I'm now driving an oil burner but isn't this excessive?

Fuel consumption:- I regularly get about 10km to the litre despite a heavy right foot.

Engine oil consumption is not at all noticeable.

Any help / advice / theory on where this oil is coming from will be greatly appreciated.

(Worn rings / valve seals - next step compression test?)

tbomachines · #2 04-22-2010, 04:05 PM

How much blowby do you have? Take off the oil cap while the engine is warm and running and see how much oil vapor blows out. Or better yet, test the compression. I would gauge that as normal, but with quite a bit of blowby.

Diesel911 · #3 04-22-2010, 06:13 PM

No Turbo on the Car Blow-by is about the only source of the Oil in the Intake Manifold.

Even with leaking Intake Valve Stem Seals I am inclined to think the Oil from that would not get into the Manifold.

However, worn Exhaust Valve Guides and worn Valve Stem Seals could cause more Blow By in addition to any Blow By from the Pistons and Cylinders.

(My Father had a gas Car with worn Exhaust Valve Stems/Guides and if he left the Crankcase Breather on the Crankcase Pressure would get high enough it would cause an Oil leak around his Oil Pan. Driving without the Breather on stopped the leak but brought tears to your eyes and you had to drive with the windows down.)

Some have had luck soaking the Pistons/Cylinders with Marvel Mystrey Oil to free up sticking Piston Rings.

Some info from one of the threads:
Marvel MM oil results sticky rings
Origional thread also has + response
Compression Test...how low is low.....

Well it loosened the carbon as the compression has increased in the two low cylinders! # 3 was 320 is now 380 and #5 was 160 and is now 340! Drove it about 20 miles hard and fast, there was some carbon coming out the exhaust! Will be taking iton two longer trips this next week: Monday I'll be going over to the coast (SLO) and the SoCa gtg on next Saturday. The trip over the Grapevine should help!
Email response about if it reduced blow-by
The blow by was reduced and also with the nice drive to San Luis Obispo my rpms are lower than they were before! Before 65@3,250 now 2,850, before 70@3,500 now 3,150? and boy does it have power... but the glow plug light is now out (starts ok but the weather is warm. The relay works, so I'll be checking the plugs) and the fuel gauge is dancing (ground?). Oh, well gives me something to do...

Other than an Engine Overhaul there is not too many choices to decrease the Blow By.

It would help if your Camshaft and Fuel Injection Pump Timing were all within spec and if your Fuel Injectors were within spec.

Stretch · #4 04-23-2010, 02:45 AM

Interesting responses guys - thanks...

The blow by (warm engine cap off) is present but it doesn't seem too terrible to me - not as bad an Audi I once went to see - I could hardly put the cap back on!

Marvel does indeed sound like a marvel. I'm now guessing it is something like that as I think the car had been standing for a long time before I bought it. It needs a bit of love and a good clean in some places.

layback40 · #5 04-23-2010, 05:34 AM

army,
It would be worth your while to check to make sure the oil remover on the top of the cam cover is not full of crud, the blow by is supposed to go to the inlet manifold oil free, with the oil removed in the oil remover.

Stretch · #6 04-24-2010, 02:24 PM

Quote:

Originally Posted by layback40

army,
It would be worth your while to check to make sure the oil remover on the top of the cam cover is not full of crud, the blow by is supposed to go to the inlet manifold oil free, with the oil removed in the oil remover.

Thanks for the tip layback40 - I went and had a look today. This is what I found:-

And inside the pipe:-

Nice and clean - but is there a bit missing?

Shouldn't there be a sort of brillo pad / gauze filter in there - or is it meant to be just a pipe?

layback40 · #7 04-24-2010, 10:27 PM

I dont know about Mercedes, but most others have some sort of oil catching gauze in there.

Stretch · #8 04-25-2010, 06:45 AM

Quote:

Originally Posted by layback40

I dont know about Mercedes, but most others have some sort of oil catching gauze in there.

Thanks for your response - I'll check with the dealer tomorrow.

vstech · #9 04-25-2010, 12:50 PM

I see normal oil to me.
it looks like your cam cover gasket is leaking oil, and needs replacement. the oil in the exhaust manifold, got there when you opened the bolts holding it in place, it just dribbled down.
note how dry the rest and the area around the oil is.
no way it would be that way if liquid oil was flowing into the manifold.
the intake seems fuller, but there is a ton of wet oil on the outside of the manifold.
aside from the tiny catch can in the cam cover, there is no external oil vapor catch can on the 81, so I'd clean everything up. maybe go ahead and change all your valve seals while you have it open, and not worry about it.
put new gaskets in there, and drive happy.

Stretch · #10 04-25-2010, 04:27 PM

Quote:

Originally Posted by vstech

I see normal oil to me.
it looks like your cam cover gasket is leaking oil, and needs replacement. the oil in the exhaust manifold, got there when you opened the bolts holding it in place, it just dribbled down.
note how dry the rest and the area around the oil is.
no way it would be that way if liquid oil was flowing into the manifold.
the intake seems fuller, but there is a ton of wet oil on the outside of the manifold.
aside from the tiny catch can in the cam cover, there is no external oil vapor catch can on the 81, so I'd clean everything up. maybe go ahead and change all your valve seals while you have it open, and not worry about it.
put new gaskets in there, and drive happy.

Thanks I did notice the cover gasket was shot but I didn't think it was dumping too much down the side of the engine... I'll have another look tomorrow (when it is light). You've got some sharp eyes there vstech thanks for the input.

BlueCrayfish · #11 04-26-2010, 03:40 AM

Quote:

Originally Posted by Army

Nice and clean - but is there a bit missing?

Nope.

Stretch · #12 05-08-2010, 12:57 PM

For those that are interested here's a picture of the progress so far.

I've cleaned up the inlet manifold - total de-grease - and shot blasted the exhaust manifold, then repainted it in heat resistant paint. I've just adjusted the valve clearances and replaced the rocker cover gasket and the manifold gasket. So I'll report back if it all works (after I've got the suspension rebuild done and the wheels back on!)

charmalu · #13 05-09-2010, 11:53 AM

Looks good, I like a clean engine bay. did you replace the 2 rubber elbo`s on the valve cover and intake? they can make a mess as they age.
also the oil cap gasket on the valve cover is replace able. probably about $2 - $3, don`t need to replace the whole cap. those old metal caps are getting harder to find.

Charlie

Stretch · #14 05-09-2010, 02:52 PM

Quote:

Originally Posted by charmalu

Looks good, I like a clean engine bay. did you replace the 2 rubber elbo`s on the valve cover and intake? they can make a mess as they age.
also the oil cap gasket on the valve cover is replace able. probably about $2 - $3, don`t need to replace the whole cap. those old metal caps are getting harder to find.

Charlie

Hi Charlie,

Thanks for the tip - I have actually already put two hose clips on those elbows. I'll see if I can get the bit of rubber for the oil filler cap.

Stretch · #15 08-10-2010, 01:38 PM

Update:-

Well I got everything back together and found engine oil dripping out of the exhaust manifold after idling the engine for about 10 minutes...

I've recently performed a cylinder pressure test and found on a cold engine a pretty uniform leakage of 55 - 60%. The air was noticeably escaping from the oil filler cap.

Could this amount of oil be the cause of anything other than valve seals / guides?

The bottom end of the cylinders seem to be OK as there was minimal noise coming out of the oil filler pipe during my leak tests. However, I've only tested at TDC...

Any thoughts anyone?