Update: Last night when I left work, rough running with stuttering till car was warm. Drove home, all sounded great after 5 miles on the interstate. I made a mistake when I checked the oil level yesterday. My parking spot at work is on an incline and when I checked my oil level at home on level ground, oil level is fine. No significant oil consumption in the past 800 miles. I have had my car plugged in since 4AM and will leave for work in an hour. I checked my Glow plug resistance and all plugs are at the same level, 1.5 ohms. That is higher than what dieselgiant found on his. I believe he said his were .6ohms.
Does anyone have the true reisitance numbers from MB? The service CD does not give a resistance, they just state that the resistance should not be infinity.
Thanks for all the info and help.
John
1986 300sdl with 90,800 miles

It most likely glow plugs, but it could also be the valve stem seals. over time they get hard and crack or shrink and allow oil to seep down the valve stem overnight and into the cahmbers. So when you start it up in the morning you get the blue cloud out of the tail pipe. this usally occurs when the car sits for a few hours or overnight (longer periods).


Steve

Glad to see you are using diesel rated oil.

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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

Started my car after having it plugged in for 5 hours. Started absolutely perfect, no smoke, no loud noises. I guess this means it is glow plug time. Here is the question; Remove intake manifold to do this? Remove fuel lines separately, leave them attached to the intake manifold?
Who has done this and what is the easiest method?
1986 300sdl OM603
John

I can't tell you how happy I am for you! Glad to see that it could be something fairly cheap!!

I took my manifold off, but I have an 87 300D. The engine compartment is a LOT tighter. The fuel lines are not attached to the intake manifold. I believe you will need a deep 12MM socket to make your life a lot easier. I bought one at auto zone for about $3. They also carry the glow plugs for $9.99 each. Make sure you buy BOSCH. If they don't have them, order them from Phil. Order about 4 80A strip fuses while you are there. You might also want to buy the $50 glow plug hole reamer. I didn't, but should have I guess.

Make sure the wires that connect to the top of the glow plugs don't end up touching the block. You will blow the fuse in about 2 seconds.

-Jim

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1995 S350D, Green with black leather interior.
Bought January 2008 w/ 233,xxx miles.
I did 22,000 miles during the first year of ownership.

Based on the symptoms described it is also possible the glow plug relay is not staying closed long enough. On my 1987 300TDT the glow plug relay failed in a manner that the glow plug light would only stay on for a one second regardless of how cold it was and the relay would only stay closed for a total of 6 seconds as opposed to the normal 30 plus seconds. The glow plug relay varies the duration it stays closed depending on the engine compartment temperature. There is no afterglow on the 1986/1987 300DT and 300TDT. I believe the after glow started on the 1991 models.

The 1.5 ohm resistance for the glow plugs just doesn't seem high enough to indicate a failure. Were the glow plugs disconnnected from the relay during testing? How long is the glow plug lamp staying lit before it goes out?

I would verify the glow plug relay is operating properly as well before changing the glow plugs.

Hope this helps.

-Steve

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1987 300TDT smoke silver w/ burgundy leather interior
2000 VW Passat wagon indigo blue w/ beige leather interior
1985 Mustang SVO
1970 Chevrolet K10 fleetside, shortbed

I disconnected the glow plug relay and measured the resistance from the plug that goes into the relay. Normally my light stays on for 10-30 seconds depending upon temperature. MB recommends that you test the glow plugs with an ammeter while they are glowing, but I do not have one.
I do not know how long these plugs have been in on this motor. They could be original.

I believe the discrepancy is due to lead resistance in the metering. I wouldn't worry as long as the readings are all within a few percent of each other. Normally the 0.6 Ohm reading would be read with a four wire bridge type of meter, a hand held el-cheapo meter will probabbly show a Ohm or more for the leads. If your getting the full heating current I wouldn't be in a hurry to replace glow plugs, as I like to clean the crossover pipe and intake when I am messing with the GP's. I always change them all when I have even one bad GP due to all the work necessary to get down to them in the 603 engine, you wind up replacing the plastic clips that hold the injector lines and all the labor involved, plus usually a short time later another GOP fails, then another following that. Its the light bulb effect if you've ever seen Christmas lights start to fail you may as well change out the whole string because statistically tungsten wire has a bell shaped curve for time vs number of failures. Glow plugs also use tungsten wire for the resistance material.

I doubt you have the original GP's in there unless its a VERY low mileage car.

As for oil level, you definitely have to be on PERFECTLY level ground to get a valid reading. It has been noted that filling the sump to the top of the mark on the dipstick (the "full" line) may result in increased oil consumption, so I fill mine to the midway between the add oil line and the full line. I only add oil after about 3000 miles of driving, or less depending on if I have done any sustained high speed driving as that seems to raise oil consumption.

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'95 E320 Wagon my favorite road car. '99 E300D wolf in sheeps body, '87 300D Sportline suspension, '79 300TD w/ 617.952 engine at 367,750 and counting!

I never advocate spending money without a suspect reason. Your car has about 100k. Do you have the service records? If so see when if ever the injection pump timing was checked. If no record you might ask someone who owns the appropiate indicator to check it. Very quick proceedure compared to the earlier drip test models. It might never have been done since new. You may or may not be lagging a few degrees. It could be reflected by your start up symptom. The previous owner was so aged anything is possible here. Could be even the original glow plugs getting tired. Other than replacement the only test is current draw. There is no indication you have any problem that would indicate it is time for the car to go at this point. Believe me a true 98 k is nothing on that engine.

My opinion is you are seeing the first symptoms of head gasket failure. The fact that it is burning oil and knocking while cold makes me think the gasket is failing at the front of the block and pumping enough oil into the cylinder to cause detonation (knock). When the engine warms up the head expands enough to seal the leak.
This opinion is based on my experience with the 87 300SDL I purchased three weeks ago. It was knocking, smoking profusely and blowing more oil out the exhaust (with the turbo off the engine) than I thought possible for a head gasket. I removed the head last night and found a severely failed head gasket at the front of #1 cylinder. The metal ring around the cylinder had actually sheared in half and was pushed into the oil gallery.

I realize this is bad news but your symptoms just don't sound like a glow plug problem to me. My two cents,
Gene

the fact that when you rechecked oil level you hadnt burned any and that plugged in overnite it started fine makes me think nothing is wrong at all my engine has 397000 miles on it and it was 24 degrees out this morning when i started it If any mosquitoes were left they departed with all the smoke but 15 seconds later it was all smooth no smoke and ran fine I dont even plug mine in till it gets to 10 degrees My father will put his outside from a heated garage on a 0 degree niight just to see if it will start in the morning (damn engineers) of course his is just a baby with 237000 miles

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commercial fisherman diesel in my blood in my boats trucks and Dear old Dad has had me drivin them since i got my first license in 1968
1986 300 SDL 427654
1999 Chevy Crew Cab Dually 225423
1986 300 SDL 287000 Dad's
1987 190 Turbo 158000 Mom's (my inheritance)

Any more progress on this thread?

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91 350SD
14 F150 Eco
19 Fusion Hybrid
11 GT500

I miss my W124. That car was really something, it could cruise at a 100 mph and not even work hard...

Yes the '87 turbo diesels run great, for a diesel they do the job.

By the Time you get very Good at Fixing cars you are in your 60's and Life is serious and your Body is so Sore that you can't enjoy it
sorry I felt this way too after wrenching on the cars this weekend! and have to apply the applicable age bracket

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'95 E320 Wagon my favorite road car. '99 E300D wolf in sheeps body, '87 300D Sportline suspension, '79 300TD w/ 617.952 engine at 367,750 and counting!

What's the status here? Some comments... oil consumption is VERY poor at 800 miles per quart. It should be 4000-6000 miles per quart on a good 603. A compression test will show if the head gasket is failed in a manner that's pulling oil in. Second guesses are valve stem seals or turbocharger seals.

The starting issue... there was no afterglow in 1987. It can be retrofitted. When temps are cold (say, 40°F or colder) do NOT start when the glow light turns off. Wait an additional 5-10 seconds. The colder it is, wait even longer. THEN start the car. This alone makes a big difference. But first test the plugs... meter error aside, they should be in single-digit ohm readings... failed plugs are usually hundreds, or thousands, of ohms (or totally open).

Bad glow plugs should have NOTHING to do with oil consumption.

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Dave
Boise, ID
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