I've been reading up on blow-by in here, but I'm not sure if that's what I was seeing...
When I did a diesel purge this weekend, I noticed, sitting in the car with the hood up, that when I reved it pretty high I would start getting smoke coming from somewhere in the engine. It looked like it was somewhere around the air filter. Is this blow-by? Or if not, what is it and should I be concerned?

I'm realizing as I write this that I should have checked if that arm off the air filter is on there right.
Any thoughts?

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1983 MB 300SD Turbo Diesel

The Drain Tube Under The Housing Is Probabaly Not Connected. Check That.

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1980 500SE/AMG Euro
1981 500SEL Euro
1982 380SEL
1983 300TD
1983 500SEC/AMG Euro
1984 500SEC
1984 300TD Euro
1986 190E 2.3-16
1986 190E 2.3
1987 300D
1997 C36 AMG
2003 C320T 4matic

past: 1969 280SE 4.5 | 1978 240D | 1978 300D | 1981 300SD | 1981 300SD | 1982 300CD | 1983 300CD | 1983 300SD | 1983 380SEC | 1984 300D | 1984 300D | 1984 300TD | 1984 500SEL | 1984 300SD | 1985 300D | 1986 300E | 1986 560SEL | 1986 560SEL/Carat | 1987 560SEC | 1991 300D 2.5 | 2006 R350

You mean vent tube?

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http://superturbodiesel.com/images/sig.04.10.jpg
1995 E420 Schwarz
1995 E300 Weiss
#1987 300D Sturmmachine
#1991 300D Nearly Perfect
#1994 E320 Cabriolet
#1995 E320 Touring
#1985 300D Sedan
OBK #42

there is a drain tube that leads from the bottom of the air filter housing that leads down to the oil pool at the bottom of the engine. If you take your air filter houseing off you will see about a 1/2" tube opening. That mates up with the oil separator in the air filter housing. If that is not lined up then the oil that is separated from the blow-by air delivered from the top of the valve cover will simply dribble down and hit the exhaust side of the turbocharger.

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Peach Parts W124.128 User Group.

80 280SL
85 300SD
87 300TD
92 300D 2.5 Turbo
92 300TE 4Matic

Blow-by is oil "blowing by" the rings or valve stem seals. It results in blue smoke out of the exhaust pipe. The oil is getting in the combustion chamber and being burned by the engine which makes the blue smoke. If you suspectg blow by you can do a leak down test to determine if it is the rings or not. If it is the rings, you are looking a an engine rebuild. If it is through the valve seals, you may be able to just replace the seals. But if the valve guides are worn, you will need a vavle job.

How much oil is it losing between oil changes? Is it leaking oil also? If it is not losing oil than you have no blow-by.

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Doug

1987 300TD x 3
2005 E320CDI

Blow by can also be determined by an oil anaylas [sp.?] too, correct?

Cheers,

Bill

No. Oil analysis only tells you whats in the oil. Blow by is a mechanical part of the engine and oil has little effect on it.

Gotcha.

Thanks for the correct spelling of anaylis.

Cheers,

Bill

Isn't there a way to measure blow-by by taking the oil cap off?

I may look at a 300CD that is on ebay...it's in my area.

I could report back to everyone about the condition..

The bidding ends at 8 pm or so Wednesday evening...

He says its in excellent mechanical condition, but a bit rough cosmetically.. i will especially look for rust and bondo...

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1989 300ce 129k
( facelifted front,updated tail lights, lowered suspension,bilstein sports, lorinser front spoiler, MOMO steering wheel, remus exhaust,stainless steel brake lines). (Gone)

1997 s320 154k (what a ride). Sold with 179k miles. Replaced with Hyundai Equus

1994 e320 Cabriolet 108k



1972 280se 4.5 153k Owned for 12 yrs, sorry I sold it


[/SIGPIC]

www.dieselgiant.com
Go to the MB maint page.
Scroll down to the last video, blow by. This shows a perfect engine.
On your car: pull the air cleaner and look for oil & deposits. Filter should be clean but may show some darkening where the breather tube enters.
If your blow by looks anything like a 2 cycle engine, DO NOT BUY! Exhaled strong puff on a cigar, DO NOT BUY. Steam coming off my head when ... ok. Smoke made by a cig in an ashtray, ok.
Try this at idle and 1k RPMs.
Strong blowby can cause a runaway diesel!

There are measuring tools designed to measure the amount of blow-by. Also, as someone noted the other day, there is suck-by. The air in the vacuum pump is discharged into the crankcase.

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1977 300d 70k--sold 08
1985 300TD 185k+
1984 307d 126k--sold 8/03
1985 409d 65k--sold 06
1984 300SD 315k--daughter's car
1979 300SD 122k--sold 2/11
1999 Fuso FG Expedition Camper
1993 GMC Sierra 6.5 TD 4x4
1982 Bluebird Wanderlodge CAT 3208--Sold 2/13