There has been some healthy debate recently on forums around the web about adding 2 stroke oil to diesel fuel.
It seems by adding a small amount of 2 stoke in around a 250:1 ratio, users are reporting a much smoother, quieter engine, less smoke and better fuel economy.
Most of the modern diesel fuel sold in the UK is ultra low sulphur diesel (ULSD), and sulphur was traditionally used to help lubricate the injection pump and injectors on a diesel engine.
Now that the sulphur has been reduced, the thinking is by adding 2 stroke to the diesel, you are giving back the lubrication properties that the sulphur used to provide. In addition the 2 stroke provides a cleaning effect on the engine too, resulting in less smoke.
Having scanned many pages on the web, from Land Rovers forums, to Ford Transits forums, I cannot find one person who had a negative effect with using 2 stroke in their fuel mix. All of them report a quieter/smoother engine and less smoke, and some report better mpg.
There was a fair number of people reluctant to give it a go, and most of them had modern cars and were worried about warranty problems, which is fair enough.
But as I have a 200tdi engined 90, which is early 1990's technology when there was more sulphur in the fuel, I thought, what the heck - lets try it. After all, I run it on filtered vegetable oil, so 2 stroke shouldn't do much harm!
Its worth pointing out, you need a mineral based 2 stroke, not fully synthetic oil. It also needs to be low ash version too.
So with this in mind, I added a small amount of 2 stroke oil to the diesel fuel in a 250:1 ratio, and took the landy for a 30 mile drive.
Well, I was surprised, everything that had been reported on-line seemed to be true, the engine was much, much quieter, and seemed smoother at higher rev ranges.
Initially, I didn't see much improvement on smoke levels from the exhaust, it still smoked a little on start up, and under heavy acceleration, but it had been reported that you have to run through a couple of tanks of the diesel/2 stroke mix to allow the 2 stroke to have some chance of cleaning the engine.
I am now on my third fill up, and I can now report a drop in smoke levels. It is definitely noticeable at start up in the mornings, and looks much less during driving too.
So having seen the benefits for myself, I am a convert, and will continue adding 2 stroke at fill ups. The average 60 litre tank will need around 250ml of 2 stroke oil added for you to start seeing the benefits.
Here's some links for further reading to help you decide if you want to give it a go: