Mercedes-Benz Forum banner

1 - 8 of 8 Posts

·
Registered
1990 W124 230E
Joined
·
67 Posts
Discussion Starter #1
I have had a 1982 W123 300D for quite some time now; the car was completely restored and brought back to life in a span of three months. There is however a problem that has been there since its procurement and restoration on which I would like your expert advice. There has always been a white/blueish smoke, emitted from the exhaust constantly during the period in which the engine is idle. In the morning the smoke is thick and dense, but as soon as the engine warms up in around 15 mins the smoke is almost gone; later on, a slight quantity of smoke is present/viewed upon revving up the engine or while driving.

Is this normal should the smoke be there? I have heard that diesels do have this problem and only if the smoke is black should one worry? Never experienced a diesel before but had this been a petrol then this would have been either a case of worn out rings in the engine or even probably a gasket issue - does the same theory apply to diesels as well?
 

·
Registered
1990 W124 230E
Joined
·
67 Posts
Discussion Starter #2
The above might be a silly question - but I would like some one to tell me if I am correct or is it natural to have smoke on a diesel.

This truly is my first time owning a diesel in my life!
 

·
Registered
1982 300D Turbo, 126xxx miles
Joined
·
196 Posts
I used to have the same issue until recently, along with the assorted starting issues. A valve adjustment was the cure, no more smoke.
 

·
Registered
1985 300CD Turbo coupe, 2006 E320 CDI sedan
Joined
·
573 Posts
is it natural to have smoke on a diesel.
The blue component is almost certainly oil, so you probably should have questioned any claim of this car being "completely restored". If the engine is turbo-charged, the oil may be entering the exhaust there. No turbo - it's an engine problem; valves/rings/et cetera. When I see blue exhaust in a potential purchase, I walk away. But just so you don't feel completely deflated at this point, it's remotely possible that there's oil-contaminated fuel in the tank. Drain (or use) what's in the tank, then refill with a fresh load of known-quality #2 diesel fuel. Allow 100km or so of driving to purge the old fuel, then re-evaluate your exhaust color (both cold and hot).

On the other hand, grayish-white when cold, disappearing as the engine warms up, is normal. The white component is just condensation in the exhaust path evaporating as the system heats up. Brief instances of black smoke under hard acceleration is not unusual either. I couldn't find the exact chart I was looking for (relative to diagnosing diesels by exhaust color), but THIS ONE may be of use to you.

//greg//
 

·
Registered
1990 W124 230E
Joined
·
67 Posts
Discussion Starter #6
grohgreg - hmm...you have a point it most likely is the quality of diesel I am supplying the car with. As I gave it an over haul upon purchase and this issue of blue smoke was not present soon after the revival of the car.

The problem surfaced soon after I switched my engine oil to Petromin Fleetmaster LD 15W40(which is approved by MB as a motor oil). Drain intervals are 2500kms, followed religiously.

Next step - is to verify the various qualities of diesel available from a lab in order to ascertain the best source to be used as a vendor for the product.

In addition the valves were adjusted and checked recently, two weeks back to be exact.
 

·
Registered
81' 300SD, 82' 300D
Joined
·
4,021 Posts
grohgreg - hmm...you have a point it most likely is the quality of diesel I am supplying the car with. As I gave it an over haul upon purchase and this issue of blue smoke was not present soon after the revival of the car.

The problem surfaced soon after I switched my engine oil to Petromin Fleetmaster LD 15W40(which is approved by MB as a motor oil). Drain intervals are 2500kms, followed religiously.

Next step - is to verify the various qualities of diesel available from a lab in order to ascertain the best source to be used as a vendor for the product.

In addition the valves were adjusted and checked recently, two weeks back to be exact.
If the problem came up after the oil change, you may have put too much oil in there.
 

·
Registered
1990 W124 230E
Joined
·
67 Posts
Discussion Starter #8
Nope - in fact that was the first thing i had checked for but all was normal. Especially since i use a marked container to fill it up plus the dipstick was checked continuously over a period of time and the marking was stable and in the accepted range.
 
1 - 8 of 8 Posts
Top