79 diesel blowby

Bought 79 300TD wagon, non turbo 3.0 engine with 320,000 miles on a well maintained car. Has 3 major, possibly related, problems.
1) Very hard to start. End up having to use ether to get it to start.
2) Will not shut off with the ignition key. Have to pull the rod at the injector pump to kill the engine.
3) Oil consumption/blowby. Burns 1 quart of oil in 20 miles. Removing cap on valve cover shows much smoke.

Thought problem #2 was a bad vacuum pump. Installed two different vacuum pumps. Vehicle will still not shut down with the key. Local VW/MBZ mechanic gave the vehicle a visual check and stated bad motor by viewing the blowby from valve cover. Its hard to believe that the prior owner let the motor get to 1 quart of oil in 20 miles. Is ther another "easy" fix to restore this motor? Thanks, Craig M

[Alain V.]

1-hard to start because compression is low

2-won't shut off because you have either a vacuum leak or the shut-off valve itself is leaking

3-oil consumption because your rings & cylinders are worn

With over 300k there is nothing "cheap" you can do. It is time to decide if the cars value is worth the investment of either a rebuild or an exchange engine.

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[be459]

1)The compression is possibly low as Alain suggested. Have the valves adjusted properly first before doing anything else.

2) First check the vacuum hoses, especially the one to the shut-off valve. If all hoses are good and connected, remove the hose to the shut-off valve and connect the valve to a hand vacuum pump while the engine is running. Apply vacuum. If the engine shuts off, the shut-off valve is good. The last thing is the key switch which may not channel vacuum to the shutoff valve. It can be checked by a vacuum gauge. It may be just a disconnected hose at the switch. I assume that the engine vacuum pump is in good workig order.

3)One quart in 20 miles? I have no idea what is going on. Smoke coming out of an oil filler hole of a diesel engine is not necessary bad. My suggestion is to do a compression test.

Good luck.

David


[This message has been edited by be459 (edited 06-16-2000).]

[MikeTangas]

One quart in 20 miles? Is the filter canister properly tightened? If you are losing a quart in 20 miles, you should be able to leave it idle in the driveway for 10 minutes and have a good idea of where it's leaking from.

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Mike Tangas
73 280 SEL 4.5

In the absence of large pools of oil on the floor, it is getting burned in the combustion process and going out the tail pipe, which would mean en engine overhaul is needed. One last ditch effort, make sure your air filter is clan, if it is clogged, the engine will try to suck it's air from the crank case, aggravating any oil consumption problems. For experimental purposes, just remove it and drive 20 miles and see if it changes the situation! But don't leave it out forever!

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Deezel
87 300TDT
150,000 miles

Engine is not dripping oil. I guess that leaves combustion. Installed new airfilter and oil filter first thing when we got the car. Bought the car assuming it needed new engine. If there is another easier "fix" that would be great. If not where are reasonably prices 300 engines available. I do not feel capable to do a rebuild. Shop prices for rebuilds are huge! I guess combination of MBZ parts prices and labor get it expensive. Even prices for takeout engines is large. One local firm does compression test on takeouts and gives you the results. You are still getting a used engine, and with the age of these 79 or so 300 engines is is very old. Even the little old lady from Pasadena is going to have a lot of miles on a 21 year old car. There is a local garage that sells takeout engines from VW Rabbits (and other VW engines) from Germany. Says ther is a law on engine mileage, and these low mileage (at least for us in the USA) engines are imported to the USA. Is this a line or true. Anythng similar for the 300 engine?

I've never heard of a law on engine mileage in Germany, it doesn't sound right to me. There is a law in Japan that prevents engines from being rebuilt. Could be that someone has stretched that as some sort of line for German engines. I'm very skeptical about this.

Good luck,

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Larry Bible
'84 Euro 240D, 523K miles
'88 300E 5 Speed
'81 300D Daughter's Car
Over 800,000 miles in
Mercedes automobiles

[be459]

I have not heard of such law in Germany either, only in Japan.

How do you measure the oil consumption? Were you checking the oil level correctly?

David

[P.E.Haiges]

AT 20 miles per quart of lubricating oil,it should run with the fuel tank empty.
P E H

P.E.

I think you're right, except you will have to have just a little fuel so the injection system can provide ignition.

At 20 miles per quart, that's 80 miles per gallon, you won't need much fuel to supplement it.

Good luck,

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Larry Bible
'84 Euro 240D, 523K miles
'88 300E 5 Speed
'81 300D Daughter's Car
Over 800,000 miles in
Mercedes automobiles