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Old 05-21-2005, 08:29 PM
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Location: Denison, Texas
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Oil Leaks

I have noticed oil puddling at base of all injectors and when I shut off the engine there are tiny bubbles coming from base of injectors in the oil ,does anybody no what the cure for this problem would be, is there some sort of seal ring are something.
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Old 05-22-2005, 01:45 AM
WANT '71 280SEL's Avatar
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First the year and model would be very helpful. I'll take a stab at it. That's not oil, just diesel fuel coming in contact with oil so it's dark like oil. Diesel fuel is a very good degreaser. There are crush washers at the base of the injectors but before pulling the injectors, replace the braided fuel hoses that run from each injector to another in series. It is very common for those to leak. If that doesn't fix it you'll have to pull the injectors and reokace the cruch washers but in the meantime you'll have to have the prechambers inspected as one could be cracked. That should keep you busy for awhile.


2000 Honda Accord V6 137k miles

1972 300SEL 4.5 98k miles

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Old 05-23-2005, 09:58 PM
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84 300 D Turbo

I pressure washed top and bottom of engine to try to get to the bottom of some of my oil leaks. I have noticed a fairly large oil leak on the back of the engine head somewhere around the area where the oil feed line line to turbo is attached to the head with a bolt has anyone ever had a oil leak in this area, the oil appears to run down trans bell housing between the solonoid for the starter. It is very hard to see because of the location to the firewall could this be a head gasket leak?
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Old 05-24-2005, 12:08 AM
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Location: Lafayette Indiana
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dont know about your second problem but the first one with the bubbles at the base of the injectors (while running?) seems to indicate combustion leakage around the injectors.
[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.
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Old 05-24-2005, 12:44 AM
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Originally Posted by t walgamuth
dont know about your second problem but the first one with the bubbles at the base of the injectors (while running?) seems to indicate combustion leakage around the injectors.
Not so........the bubbles you see are the fuel/water boiling off.
Install new bleed hose, blow out base of injectors with air and watch again.
Very unlikely compression gasses getting past crush washers.....

Sorry walgamuth .....don't mean to knock your diagnosis...had many customers coming here to say, last shop said their cups where leaking and might need removing/renewing...none turned out to be so. Just weeping bleed lines.

'Corse....I've been known to be wrong...but they were mistaken !

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"A liberal is someone who feels they owe a great debt to their fellow man, which debt he proposes to pay off with your money."

Last edited by dkveuro; 05-24-2005 at 03:48 PM.
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Old 05-24-2005, 02:50 PM
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Thanks for the info i will get some new lines and give that a try .
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Old 08-08-2005, 12:00 PM
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Location: Flagstaff, Arizona
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update on both oil leaks

Hello I was wondering on an update on both of these leaks. I have a 85 300td 268,000 and am methodically working through all my oil leaks. I have a leak at the back right corner of the engine. It appears to be the turbo oil feed tube. also my two front injectors have a black liquid bubbling up at the base of them. the fuel lines are brand new and fine. the bubbles continue after I turn the engine off for a couple of minutes. Anyway seems we both have the same problems. could you update me on what you learned?
Thanks! Scott
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Old 08-08-2005, 12:44 PM
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Location: Denison, Texas
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My oil leak is still there at the back of the engine I was told that this is a common problem with this engine it is the head gasket. The injector problem was diesel leaking from the hoses.
84 300 Turbo / 320,000
96 E300 D / 55,000
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Old 08-08-2005, 01:36 PM
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It can also be leaking around the oil filter housing to block, oil filter housing to side cover, oil pressure sending unit and the crush washers that seal the pipe that leads from this side cover to the turbo.
'82 300SD - 361K mi - "Blue"

"Good judgement comes from experience. Experience comes from bad judgement."

listen, look, .........and duck.
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Old 08-08-2005, 09:20 PM
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Location: Central Oregon
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Don't forget the valve cover gasket

I'm telling you from experience that this thing can leak a lot of oil if the surface is not cleaned correctly before reseating the gasket. My 81 (just sold) had a major leak back there that I thought was major, changed the gasket but did not wire brush the seat first. Well where the old oil had leaked through it had burned onto the head and subsequently I could not get the gasket to seal well and it started dumping major amounts of oil on a long trip.
I then pulled the valve cover and cleaned that surface with a brush and the car has no leaks now. I don't think the head gasket as a usual leaking spot is necessarily true.
'99 S420 - Mommies
'72 280SE 4.5 - looking to breathe life into it
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'85 300SD Silver - Sold
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Old 09-01-2005, 04:16 PM
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I have spent some time tracking oil/fuel leaks.

Ones I have found:

- Flange where oil supply to turbo attaches - someone had used "form-a-gasket or some such stuff - Made a gasket from gasket paper and leak has gone.

- Valve cover - Rubber seal was replaced at last valve change - Just had to torque hold-down nuts a bit and leak has stopped (near back of engine)

- Injector leaks - Have new hoses. Get drips of clean fluid on garage floor.Seems to leak from middle of injector. I had this once before after rebuilt injectors were installed - I think there must be a joint in the injector bidy that is sealed with an o-ring - no solution other than to replace injectors?

- Lower connection to oil cooler leaks slightly - Have not tried to fix - likely need new o-ring or seal?
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