My truck emits a faint black smoke coming out of the tailpipe on idle. And during ascent I rev up the engine up to clear the soot. What contributes to soot? Engine oil? Fuel? or is this because the Disco is old? I change my engine oil every 3,000 miles and whenever I check the dipstick its remains black. Wil I ever see a clear engine oil?

 

Assuming that we are talking about a turbo diesel, first of all you are lucky. The soot at idle is not uncommon (if it is just barely visible). Check your air filter. Soot is simply excess fuel not burning completely. At low revs under load you will see more soot, as the turbo starts to spin up it forces more air into the engine and allows complete burn of the fuel. Quality of fuel (additives) will help with the soot. As to clean?! oil in a diesel all I can say is good luck with that. Out of the six diesels I have owned the only time I had clean oil (not BLACK) was after an oil change before starting the engine. Electronically controlled diesel engines (TDIs) are a lot better about soot and clean oil but lack some of the durability of the older diesels. I hope to put your mind a little more at ease with this.

 

You could get your fuel system reset to improve the soot issue, but you'll loose power doing so.
Best think most people with diesels do is to occasionaly add some good diesel additive to clean out the system.

 

+1 on the diesel fuel additives. I assume you are already using one though. Also use a good diesel oil as they will have the detergents and high base number to keep deposits at bay and neutralize the acids that form.

 

Ok thanks guys, I feel more at ease now. I use Mobil Delvac 15W-40 and change it every 3000 miles. Hmm I don't use any diesel additive, Ive always thought that they are just those silly infomercials that I see on TV :-) Ok what is a good brand diesel additive, can I just use any diesel additive product?

 

This brand is a good additive, when I drove semi this was the brand that we used to keep the fuel from gelling in the winter time.
http://www.fueladditiveonline.com/Fu...eAdditives.php

Use the best brand of fuel you can get and then use a additive twice a year to keep your injectors clean.
Once they are clean then using a high quality fuel will keep them clean and a additive will no longer be needed.

Bottom line, diesels are dirty, thats why they dont sell well here in the US.

 

Darn it I'm so envious of what you guys can buy in the states. Parts, oils, accessories etc. I'll just buy STP diesel additive. Thanks Spike.

 

well we are quite envious of your TDI.... so....

 

Fuel quality has alot to do with it, low quality fuels have paraffin in them and they dont burn as well and are dirtier than good fuel.

That link I posted you can order from, I dont know if they will ship to you though.