Black Oil in Air Filter - PeachParts Mercedes-Benz Forum

coldwar · #1 10-07-2004, 08:45 AM

Yesterday I changed the air filter in my '76 300D. I was quite surprised to find some black engine oil on the old filter element. Surprised because on this W115 car, the filter housing is so far from the intake manifold- way down behind the headlight and connecting to the log manifold with a 2.5" air tube. I know this is normal when the filter is in close proximity to the manifold, but on this car I wouldn't have thought any oil could get from the PCV running against the airflow way down to the filter chamber. Does anyone think there may be a problem here? BTW- my oil consumption is roughly 1 quart in 1500 miles using Irving Diesel Oil semi-synthetic 5W40- car has 139,000 miles and there are no oil leaks that I can see anywhere.

Dave in Atlantic Canada

leathermang · #2 10-07-2004, 08:58 AM

Check to see if the location showing on the air filter would match the line going to your vacuum pump... you are probably about to lose your vacuum due to a torn diaphram.....

coldwar · #3 10-07-2004, 10:23 AM

Quote:

Originally Posted by leathermang

Check to see if the location showing on the air filter would match the line going to your vacuum pump... you are probably about to lose your vacuum due to a torn diaphram.....

The line going to the vacuum pump does not go to the air filter, rather it goes direct to the Intake Manifold "log" (or plenum, I guess).

Dave

leathermang · #4 10-07-2004, 10:38 AM

If you have black oil soot on your intake filter I think you have a problem... I just don't know what it is... if you will get a 123 I can look in my MB manuals... until then you will have to wait until someone who Does know posts.... LOL

whunter · #5 10-07-2004, 10:58 AM

"leathermang", I would think that some good pictures of the engine compartment would make answers possible.

Insufficient data at this point.

leathermang · #6 10-07-2004, 11:14 AM

How close behind other diesels do you follow on the road... Do you and the MB in front of you look like NASCAR racing ? That could put some soot onto the air filter without you having any problems... until they stop too fast for your reflexes....

TwitchKitty · #7 10-07-2004, 12:02 PM

How old was that filter? Are we talking wet dripping oil or black stain?

R Leo · #8 10-07-2004, 12:37 PM

I seriously doubt that engine blowby could make it to the air filter since the stock 115 uses an oil bath filter that is remotely located from the engine.

Some questions:
How long have you owned this vehicle?

Ever checked the filter before?

Does this car still have the original filter setup (see pic)?

If it is stock, the oil in the filter will become dirty and discolored over time as it traps contaminates from the air being pulled into the engine. The filter will be dirty with this discolored oil.

Palangi · #9 10-07-2004, 12:45 PM

I think the 115 300D had a paper filter, not the oil bath type.

By the way, speaking of oil, check and see if there is a filler cap marked "OEL" on the injection pump.

R Leo · #10 10-07-2004, 12:46 PM

Quote:

Originally Posted by Palangi

I think the 115 300D had a paper filter, not the oil bath type.

By the way, speaking of oil, check and see if there is a filler cap marked "OEL" on the injection pump.

Jeez. A 300, right.

coldwar · #11 10-07-2004, 03:00 PM

Thanks all- informative and entertaining as always! I've had the car just over a month, and I'm still learning about it. This is the first Merc I've ever owned, but have had 4 VW Diesels in the past. So, I have the 5 Cyl. and it has large air filter can at front of engine bay connected to manifold with flexible air pipe- see Photo 1. The filter element is paper, not oil bath. The vacuum line from the manifold down to the vacuum pump can be seen in photo's 1 and 2- it is clear plastic, slightly yellowed, but there is no black crud in it. The third photo is the best I could get of my IP- I couldn't find any "OEL" cap on it.

The oil on my old filter was not a huge amount, but definately wet to the touch, and laying on the inner rubber ring of the filter element. The filter was in real bad shape- looked like it was in there a few years. Even so, I just can't understand how any engine oil could migrate down from the manifold to the filter with a setup like this.
Dave

TwitchKitty · #12 10-07-2004, 03:58 PM

I wouldn't be concerned until you see how the new filter fares.

The underhood pictures look good. If you feel like posting pictures of the rest of the car, we won't mind.

I am waiting to buy a 115, the owner will part with it soon. It is nothing special but it caught my eye.

coldwar · #13 10-07-2004, 04:05 PM

Quote:

Originally Posted by TwitchKitty

I am waiting to buy a 115, the owner will part with it soon. It is nothing special but it caught my eye.

My friend- you WILL FIND that any 115 IS SPECIAL! I know you will enjoy owning it.

Lycoming-8 · #14 10-07-2004, 10:25 PM

Coldwar,

"The third photo is the best I could get of my IP- I couldn't find any "OEL" cap on it."

Your's looks like the newer IP's that do not have their own oil sump. My 220D/8 had the old style and the red plastic cap is very obvious!

coldwar · #15 10-14-2004, 12:12 PM

Quote:

Originally Posted by TwitchKitty

I wouldn't be concerned until you see how the new filter fares.

Just did another check on it yesterday- this time when engine was warmed up. What I found was a noticable amount of blow-by smoke going right into the air filter chamber (engine not running), and once again, a small accumulation of blackened oil. It appears that after I shut car off, the smoke must condense back into oil at the air filter tube. I'm just not sure if this should be cause for alarm or not. As I mentioned, oil consumption is pretty reasonable- 1 quart for 1500 miles.

Dave

1976 300D W115 "Pearl"