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  #1  
Old 03-19-2011, 12:51 PM
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91 300D leaking oil everywhere...

well, it's bad...
turbo outlet dripping, intake crossover dripping, EGR that's plugged, dripping... engine running rough, head gasket to timing cover dripping... I'm worried about this poor car. it was doing SO well last summer, customer drives it off and on through the winter, and now it needs help.
I do not think it's turbo seals, it does not use much oil, I think it's all blowby. (why did MB get rid of the oil sep can?)
what's the general forum think of as a first step?

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John HAUL AWAY, OR CRUSHED CARS!!! HELP ME keep the cars out of the crusher! A/C Thread
"as I ride with my a/c on... I have fond memories of sweaty oily saturdays and spewing R12 into the air. THANKS for all you do!

My drivers:
1987 190D 2.5Turbo
1987 190D 2.5Turbo
1987 190D 2.5-5SPEED!!!

1987 300TD
1987 300TD
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  #2  
Old 03-19-2011, 03:03 PM
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A quick trip to the local self car wash with a gallon of 'Mean Green'
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1985 300D 198K sold
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  #3  
Old 03-19-2011, 03:21 PM
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X2 on cleaning!

Then a leak down test / just put some low compressed air via the glow plug hole to listen to where the air is coming out. Listen for example at:-

Oil filler cap

Exhaust

Air filter

Dip stick tube

Then look for

Bubbles in the coolant
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1992 W201 190E 1.8 171,000 km - Daily driver
1981 W123 300D ~ 100,000 miles / 160,000 km - project car stripped to the bone
1965 Land Rover Series 2a Station Wagon CIS recovery therapy!
1961 Volvo PV544 Bare metal rat rod-ish thing

I'm here to chat about cars and to help others - I'm not here "to always be right" like an internet warrior



Don't leave that there - I'll take it to bits!
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  #4  
Old 03-19-2011, 03:36 PM
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Take oil cap off and start car to see if it is blow by.
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  #5  
Old 03-20-2011, 01:57 PM
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Quote:
Originally Posted by Army View Post
X2 on cleaning!

Then a leak down test / just put some low compressed air via the glow plug hole to listen to where the air is coming out. Listen for example at:-

Oil filler cap

Exhaust

Air filter

Dip stick tube

Then look for

Bubbles in the coolant
Oh I forgot to mention - just in case others are reading! You don't need to apply daft amounts of pressure you only need very low pressures to hear the wind whistling. Start off at very pressures => 1 PSI if you can.

You don't want to turn the crankshaft by accident
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1992 W201 190E 1.8 171,000 km - Daily driver
1981 W123 300D ~ 100,000 miles / 160,000 km - project car stripped to the bone
1965 Land Rover Series 2a Station Wagon CIS recovery therapy!
1961 Volvo PV544 Bare metal rat rod-ish thing

I'm here to chat about cars and to help others - I'm not here "to always be right" like an internet warrior



Don't leave that there - I'll take it to bits!
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  #6  
Old 03-20-2011, 10:11 PM
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85 300D 4spd+tow+h4
 
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Quote:
Originally Posted by vstech View Post
head gasket to timing cover dripping...
This is one of the more frequent HG failure points I believe. Compression test for starters.
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  #7  
Old 03-21-2011, 11:45 AM
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Agreed, highly possible that it is the head gasket: #1 cyl to timing-chain cavity leak. Pull the #1 injector and crank the engine, see if any oil spits out, and look down into the prechamber for oil after cranking.

One significant risk in these engines is hydrolock. The piston actually protrudes beyond the top of the block and into the head gasket at TDC, leaving the prechamber (which protrudes down into the piston) as substantially all of the combustion chamber. This leaves 5 tiny holes to pass oil which could pool in the pre-chamber hole in the piston, during the compression stroke, so less than a teaspoonful of oil could damage your engine (theoretically even with the glow-plug out), cranking speeds might be fairly safe unless the cylinder is quite fouled with oil.

Other more expensive problems would be stuck rings, not common if running diesel or good biodiesel though (I believe that you run D2?).
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  #8  
Old 03-21-2011, 11:52 AM
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85 300D 4spd+tow+h4
 
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Quote:
Originally Posted by babymog View Post
One significant risk in these engines is hydrolock. The piston actually protrudes beyond the top of the block and into the head gasket at TDC, leaving the prechamber (which protrudes down into the piston) as substantially all of the combustion chamber.
Interesting I did not know that.
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  #9  
Old 03-21-2011, 12:20 PM
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I'm in FL for the week, will post a couple of pictures if I have them here.
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  #10  
Old 03-21-2011, 12:26 PM
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I'm sure the guy is NOT looking forward to a head replacement... ROY tells me that the 91 2.5 turbo head has been superseded with improved castings, and If it's bad, repair is unwise... replace with modern casting is best.
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John HAUL AWAY, OR CRUSHED CARS!!! HELP ME keep the cars out of the crusher! A/C Thread
"as I ride with my a/c on... I have fond memories of sweaty oily saturdays and spewing R12 into the air. THANKS for all you do!

My drivers:
1987 190D 2.5Turbo
1987 190D 2.5Turbo
1987 190D 2.5-5SPEED!!!

1987 300TD
1987 300TD
1994GMC 2500 6.5Turbo truck... I had to put the ladder somewhere!
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  #11  
Old 03-21-2011, 12:26 PM
vstech's Avatar
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and if it's been hydrolocked, then I could be facing bent rod too...
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John HAUL AWAY, OR CRUSHED CARS!!! HELP ME keep the cars out of the crusher! A/C Thread
"as I ride with my a/c on... I have fond memories of sweaty oily saturdays and spewing R12 into the air. THANKS for all you do!

My drivers:
1987 190D 2.5Turbo
1987 190D 2.5Turbo
1987 190D 2.5-5SPEED!!!

1987 300TD
1987 300TD
1994GMC 2500 6.5Turbo truck... I had to put the ladder somewhere!
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  #12  
Old 03-21-2011, 12:49 PM
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Although there is a newer casting available, the '91 had a stronger casting than the dreaded '87 castings: OM602 & OM603 Cyl. Head Revision Reference

A couple of photos. The head photo shows the flat surface with protruding prechamber, the block showing the typical piston protrusion at TDC on #1 and #6 and the prechamber pocket in the pistons.
Attached Thumbnails
91 300D leaking oil everywhere...-032a.jpg   91 300D leaking oil everywhere...-p2020001a.jpg  
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  #13  
Old 03-21-2011, 02:15 PM
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Quote:
Originally Posted by winmutt View Post
Interesting I did not know that.
When the weather was bad I got bored and started meauring this sort of thing on my OM617

OM617 (non turbo) cam profile specs, piston height specs etc

In case you are interested (I was really bored)
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1992 W201 190E 1.8 171,000 km - Daily driver
1981 W123 300D ~ 100,000 miles / 160,000 km - project car stripped to the bone
1965 Land Rover Series 2a Station Wagon CIS recovery therapy!
1961 Volvo PV544 Bare metal rat rod-ish thing

I'm here to chat about cars and to help others - I'm not here "to always be right" like an internet warrior



Don't leave that there - I'll take it to bits!
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  #14  
Old 03-29-2011, 04:18 PM
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Quote:
Originally Posted by 04 Diesel View Post
Take oil cap off and start car to see if it is blow by.

Obviously, I'm a newbie to this.....what are you gonna see if it's excessive blow-by? I hold my hand over the hole and it stays clean......but there is a bit of smoke/vapor coming out of it.
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  #15  
Old 03-29-2011, 04:23 PM
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Unscrew cap but do not remove with engine running if cap blows off there's alot of blow by.

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