Oil Coming Out of Dip Stick Tube - PeachParts Mercedes-Benz Forum

zsmith29 · #1 12-05-2008, 10:25 AM

I do not know why I have oil and little air bubbles coming out of the small hole at the top of the dip stick housing tube. I might have just noticed it recently.

I have another issue that popped up recently and it has to do with a loud, rattle, type sound coming from the engine or turbo. It sounds very bad and it is getting louder. I don't know what to do about it.

I don't know much at all about engines so any help would be greatly appreciated on these two issues.

Thanks Guy's
Zack

rrgrassi · #2 12-05-2008, 10:29 AM

On which car?

Stop driving/running the one with the problem. Sounds like too much crankcase pressure build up, or an overfilled crankcase, or excessive blowby, say by bad rings or a hole in a piston. A compression test is warranted at this point.

The noise could be a bad alternator, water pump, failing turbo, or a failing vacuum pump, based on what you said about noise location.

zsmith29 · #3 12-05-2008, 10:32 AM

The noise is coming form the 300D.
It started about 2 weeks ago. Is there any way to tell if it is a problem with the turbo? I am thinking that it might be the culprit.

I do have quite a bit of blowby with this engine and I am due for a valve job. Do you know of anything that I could look for and check when I am performing the valve adjustment.

rrgrassi · #4 12-05-2008, 10:38 AM

Do a compression check, pre and post valve adjustment. Then do a wet compression check.

You can remove the u tube, and with the engine off and cold, feel for play. Very little side to side play, is normal since the turbo spins a minute cushion of oil. Also make sure it spins freely. There should be no end to end or lateral play of the turbo shaft.

zsmith29 · #5 12-05-2008, 10:51 AM

How or where can I do a compression check and also what is the "U Tube"?

Dee8go · #6 12-05-2008, 11:02 AM

You Tube?

zsmith29 · #7 12-05-2008, 11:04 AM

Is the u tube the thing that re-circulates the air into the turbo?

rrgrassi · #8 12-05-2008, 11:16 AM

The u-tube is the black plastic 180 deg that goes from the air cleaner to the turbo. You can see the turbo's impeller when this tube is removed.

You have to have a compression guage that screws into a GP hole or injector hole. You crank the engine and you will see what compression the cylinder has. All GP's or injectors must be removed to do this. A wet test uses a tablespoon of oil in each cylinder.

jt20 · #9 12-05-2008, 11:34 AM

RRgrassi, Is there any way the turbo could be sending pressurized air to the crankcase via drain tube if it has comprimised a seal on the compressor shaft?

rrgrassi · #10 12-05-2008, 11:55 AM

I guess it's possible. I have not had to disassemble the turbo yet. My car has 256k miles on it. If the oil spits out at idle, it's probably not from the turbo.

A turbo expert should chime in.

zsmith29 · #11 12-05-2008, 01:14 PM

I was looking at it earlier and it seemed to spit out mainly air w/ small amounts of oil.

I am more concerned about the rattle noise that is coming form the turbo, vac pump, engine, or around that area.

I got a long screwdriver and listened around in that general area. The only place that I heard a distinct noise was from the front of the engine.

I dunno what to do, I might just do the valve job and look around. Then if I don't see anything I will just drive it until she dies or I sell her.

I have heard that rebuilding an engine like this is really not worth it in the long run

jt20 · #12 12-05-2008, 01:19 PM

I can only offer guesses here. But if you think the rattling and bubbling are incidental, remove the vacuum pump and fully inspect. The turbo is not close enough to confuse these two.

It is very possible to imagine that the vacuum pump is failing, failed etc.. and dumping air into your crankcase adding to perceived blowby and sending the excess out your dip tube.

rrgrassi · #13 12-05-2008, 01:36 PM

You can remove all the drive belts, start the car and see if the noise goes away. That would be my first move. If it is still there, then check the vacuum pump and turbo. It would help if you could post an audio/visual file with the noise as well.

Also check the oil level. Too high can cause back pressure into the dipstick tube.

pawoSD · #14 12-05-2008, 04:33 PM

The engine in my dad's new SD was doing the same thing, burning tons of oil, sending some out the dipstick, running VERY poorly....barely enough power to get up the driveway. We swapped motors. The old one is under a tarp in the snow right now, I'll tear it down in the spring to see what happened....

AmishThunder · #15 12-05-2008, 04:34 PM

Also, check the rubber bushings beneath the air cleaner assembly, those can fail and cause BAD rattles... There are three of them. To check it, start the motor and use both hands to put pressure on the air cleaner assembly. If the rattle stops, that's the issue...