Many thanks to all who wrote back yesterday, lots of friendly and knowledgeable people around here!

OK, so here's my problem, I have a 1985 300 SD which is not passing inspection because, so they tell me, there is "too much smoke" (How much is "too much"? They were unable to tell me this).
The car does not appear to be burning oil unduly, or leaking coolant into the oil, or vice versa. I added some biobor and diesel kleen to the tank, gave it an Italian tune up, changed the oil and fuel filters, and it's still smoking. I would say the smoke is bluish/grey/white, if that helps, but definitely not black-black.
Here's my question: it has been suggested I do a valve adjustment and an ALDA service (clean the banjo bolt). Seems to me there is the possibility it is a head gasket issue, in which case it has been suggested to me that it would be cheaper to swap in a rebuilt engine than to replace the head gasket. If the valve job doesn't fix the problem, and I have to swap the engine, then the valve job would be for nought, right? The valve job seems like a big enough deal that one wouldn't want to do it if there are any doubts that that's going to take care of the problem.
So, what's the quickest, cheapest, most reliable (I know, wishful thinking here, probably) way to diagnose whether the issue is the head gasket
or something else?
The compression seems OK. Any ideas or suggestions would be most appreciated!
Jim

Have you done a compression check? A valve adjustment should be one of the first things tried. It is also one of the least expensive. Just need a valve cover gasket and 14 mm wrenches and a feeler guage. An injector not spraying properly can also give excessive smoke.

How much blowby?

A bad head gasket would show other issues like leaking/losing coolant, running too hot, power decrease, low compression on one or my cylinders, even with the wet test etc. If it is low on the wet test, and after a vavle adjustment does not raise the compression, then look for a burned valve or a cracked head.

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RRGrassi


70's Southern Pacific #5608 Fairmont A-4 MOW car

13 VW JSW 2.0 TDI 193K, Tuned with DPF and EGR Delete.

91 W124 300D Turbo replaced, Pressure W/G actuator installed. 210K

90 Dodge D250 5.9 Cummins/5 speed. 400K

Does is smell like burning coolant, diesel or oil?

__________________
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1995 E420 Schwarz
1995 E300 Weiss
#1987 300D Sturmmachine
#1991 300D Nearly Perfect
#1994 E320 Cabriolet
#1995 E320 Touring
#1985 300D Sedan
OBK #42

smoke:
bluish = motor oil in the exhaust
white = coolant or unburned fuel in excess, in the exhaust
black = partially burned fuel in excess in the exhaust.
you stated white to bluish, sounds like blowby pushing oil vapor into your intake. do a teakettle test on the oil fill cap. then look for solutions to the blowby.

__________________
John HAUL AWAY, OR CRUSHED CARS!!! HELP ME keep the cars out of the crusher! A/C Thread
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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!

Thanks, guys. John, what's a teakettle test? I'm gonna go out and smell the exhaust at lunch, will let you all know. I appreciate the input.

Jim

Take you oil cap off you engine and just place it back on (without securing) see if it bounces around on top of the valve cover with engine running.


Don't let it flip into the fan (be careful)

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00 E420
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86 Holden Jackaroo Turbo D
86 300SDL
(o\|/o)

You have a long way to go before worrying about the head gasket, unless the smoke smells sweet like coolant, or there is oil in the coolant etc.

If you do have a lot of blowby, the updated breather hose that goes from the valve cover to the air cleaner can help prevent oil getting to the intake. Total cost = $13

Does the car burn a lot of oil between oil changes?

Next thing I would do is a Diesel Purge. Dieselgiant.com has a good writeup. Its like a super duper cleaning for the fuel system.

Next is the ALDA banjo line service.

The valve adjustment is a good idea no matter what. When doing the valve adjustment, check the timing chain stretch. You may need to put in a 'woodruff key' to correct it.

Next, check out you injection pump timing. A slightly late pump can cause white smoke.

Hope this helps,
dd

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-------------------------------
'85 300D, 'Lance',250k, ... winter beater (100k on franken-Frybrid 3 Valve Kit)
'82 300D, 'Tex', 228k body / 170k engine ... summer car
'83 300TD Cali Wagon 210k, wife's car

I have a general idea that as these cars get older and lose compression, they start to smoke more because they aren't burning the fuel completely.

Have you given any thought to selling the car if it won't pass DC inspection? We don't have any emissions test on diesels in Virginia.



Ken300D

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1982 300D at 351K miles
1984 300SD at 217K miles
1987 300D at 370K miles

Hello all,
Thanks for all of the advice. OK here's the update:
exhaust smells like exhaus, not coolant, maybe faintly of diesel.

I cleaned the EGR with WD-40, didn't seem to do too much.
I tried the teakettle test: with the breather hose attached, the oil cap bounced a little bit, and no colored smoke (of any color) came out of the oil cap. With the hose off, when I plugged the intake, had the same result, cap bounced a little, no smoke, engine did not shut off when plugged.

Now, I am looking, when I rev it up to ~3k rpm I get a burst of real black/brown smoke, otherwise at low RPM it is a light grey smoke, and not too, too much of that, but enough, if you know what I mean.

I cleaned out the banjo bolt on the ALDA, it wasn't too bad, this didn't seem to have a big effect either.


So here's what I have next up:
a Diesel Purge treatment
Breather hose replacement
a valve adjustment

Sound reasonable? Any comments/new ideas from the symptoms here?
Looking forward to your sage advice,
Jim

I'm not sage (or Rosemary or Thyme), but I'll chime in. With your description of smoke, and your description of your blowby, I would suspect unburned diesel smoke to be the problem. Some ideas:

Injector return lines leaking have caused smoke for me.

A peeing injector can cause smoke. Solution: Spray test from Bosch service center.

Is the air cleaner oily? If so, check the oil separator in there.

How about timing chain wear (some call it stretch). A worn timing chain can cause valves AND IP to be out of whack causing fuel smoke.

Turbo seals can cause blue smoke, but it sounds like yours is not in that category.

Maybe try some fresh fuel as well. I saw a video once of an SDL that had bad winter fuel and OMG, it was like a mushroom cloud of smoke.

Good luck!

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1998 E300D, 287k, barely broken in.

[quote=GRIESL;1566734]I'm not sage (or Rosemary or Thyme) What happened to Parsley, daddy-o? Alright, sounds like a plan on the valve adjust etc. I don't think a purge will help, but I'm sure it won't hurt. Sounds like normal smoke. Both of mine pretty much do that.

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83 SD

84 CD

A few questions:
Are you using a lot of oil?
Are you loosing coolant?
Is your engine running rough?
I the answer to all is no, then I would suspect a fuel problem and agree with DieselDan...... have your timing checked.

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Sam

84 300SD 350K+ miles ( Blue Belle )

Not using a lot of oil, not losing coolant. Engine is running a little rough (i.e. there's a bit of rattling), but hard to say it's not the engine mounts/muffler.
The injector return hoses don't appear to be leaking, I replaced the one that was. Now that I look at it, cleaning out the EGR does appear to have made some improvement.
Can one check the timing easily oneself?
Hopefully this'll come together soon...gonna do the big stuff this weekend.
Thanks again!
Jim

Air cleaner is taking in some oil, where is the oil separator located? What kind of repairs can be done on it? Seals? Replacement?
One last question, it was suggested to me that running down the tank, then loading in a few gals of vegetable oil sometimes can be a quick fix for smoking. Any reason this might be a bad idea?
Jim

The oil/air separator is inside the air cleaner. On your blowby test, if you are going to plug the line, the oil cap has to be on tight so it can't bounce around. After you plug the breather hose, you count the seconds it takes for the engine to die. You do this at your own risk, as engine seals have been know to blow. The reason for the engine dying is the buildup of pressure inside the crankcase. An engine with 0 blowby will not die with this test.

Diesels do smoke, so veg oil will not make it smoke less.

__________________
RRGrassi


70's Southern Pacific #5608 Fairmont A-4 MOW car

13 VW JSW 2.0 TDI 193K, Tuned with DPF and EGR Delete.

91 W124 300D Turbo replaced, Pressure W/G actuator installed. 210K

90 Dodge D250 5.9 Cummins/5 speed. 400K