Let me shed a little light on what smoke from a diesel reveals. First of all to give you a little background so you know I have some experience with diesels. Rebuilt my first diesel engine in 1958 when I was 15 yr. old and have been involved with diesel engines ever since. Got my nickname “dieseldoctor†in the early 70’s when I was a field representative for a large construction equipment dealer doing repairs on heavy equipment. I pulled up to a dozer with an engine problem one-day. As I got out of my service truck one of the guys said, “boys, the dieseldoctor is here. Everything’s going to be ok.†The name stuck and for years around 6 counties of North Carolina I had a reputation of being the man to call if you had problems with an International, Cummins, or Detroit engine. Worked on a few Cats (mostly in bulldozers I owned) but wasn’t as familiar with them as the others. Will try to add a couple of pictures of an engine job I did right where it broke down. This was when I had 15 bulldozers split into 5 crews clearing and maintaining power line right of ways for power companies in NC and SC. To see more pictures of this operation you can go to this link and click on Skyline Construction.
http://pg.photos.yahoo.com/ph/dieseldoctor_1/my_photos
(Couldn't get pictures to upload but if you are interested go to above link to see them)
Now lets talk about smoke from a diesel. White smoke is a sign that the fuel to air ratio is correct but there is not enough heat to completely burn the fuel or that an injector or injectors are not atomizing the fuel enough for it to be completely burned. For some engines the lack of heat problem is normal on a cold start. (Anybody remember the Cat 3208? Crank one up on a cold morning and someone will probably call the fire dept that the truck is on fire. Lol). Once the heat builds up in the engine the smoke clears and everything is fine. If the injectors aren’t atomizing the fuel sufficiently for it to be completely burned the temperature in that cylinder or cylinders will drop thus causing the white smoke. The unburned fuel will dilute the oil film on the rings and cylinder walls and will eventually lead to gauling of the piston and cylinder. In other words if you see much white smoke the life of your engine is being shortened.
Black smoke is a sign that there is too much fuel in relation to the air that is going in the cylinder. In other words the fuel to air mixture is too rich. Have you ever started a gas engine that has a choke and seen what happens when you have the choke on too much? Smokes black smoke doesn’t it. Once again the extra fuel is not being burnt so the oil film is bring diluted. Again this is not good.
Now this thread started about a Sprinter. I have never touched a Sprinter engine and about all I know is what a friend of mine who supervises three shops for a big package delivery service has told me. He has about 80 Sprinters under his care. What he tells me, when asked about this smoke problem at start up or after idling is that he has seen this several times and it is usually an injector going bad. Replacing the injector will cure the smoke problem. But it is not unusual down the road (80,000 to 150,000 miles) that this cylinder will gaul. Cure for this is a new engine. Fortunately for this large company DC has been picking up a lot of the bill. (Prorated by mileage). Unfortunately for a single truck owner there probably won’t be any help. I have talked to three individuals that have had an engine failure in less than 150,000 miles. All had had injector failures before. One had an extended warranty that DC used to sell (It is my understanding they don’t offer this extended warranty anymore. That should tell you something.) and she got $4000.00 for her old engine. Bill for engine replacement was $12000.00. The other two got nothing.
My best advice is finding a service manager that you can talk to and insist that they cure the smoke problem. If they can’t cure the problem, request that they have a factory representative investigate the complaint and meet with you to discuss it. At the very least make them write up a work order listing all details and THEIR version of what is going on with the engine. Get a copy of this work order and keep it in a safe place. It could be a valuable piece of evidence in court later.
Good luck,
Dieseldoctor