Diesel fuel oil flush

[hz293]

just changed oil and filter. 4 quarts and a little to go. Ran engine before changing and after but doesn't look as clean as oil put in. Is it possible I have some sludge in there. What's the scoop about running diesel fuel, draining and putting new oil and filter in again.

 

[bruceb58]

Don't worry about it. Don't do the diesel fuel flush.

 

[Grub54891]

Well sometimes there is sludge, one I bought this spring was not maintained very well by the po. I had to change the oil 3 times to clear it up. Use cheap oil and some sea foam, then change it out a couple times. It works well. Years back at the farm, when I was a teenager, I bought an old car. Grandpa pulled the stick and said it needs a change,I just did that the day before, So he dumps about half quart diesel in it and runs it for 5 min. Dumped the oil, what an ugly sight.... let her drain overnight and re-filled, oil looked great after that. Sea foam is similar to the diesel flush only with additives of some sort.

 

[Silvertip]

There is a much better product for sludge removal. Any auto store will have RISLONE. Follow directions on the container. This stuff works. I speak from experience. -- many years of it.

 

[gm280]

There are a lot of engine flush products on the market. But I warm you, if you use an engine flush, you can easily make the engine burn more oil afterwards and possibly harden seals and such. The products do clean the engine, but also removes sludge and varnished up areas from everything loosening up the entire engine. So use what YOU think is the best for your situation. JMHO!

 

[bruceb58]

I just looked at your old posts and see you are sucking the oil out of the dipstick on a Mercruiser. You are not getting every last ounce of oil out and that is why your oil looks a little darker. Same is going to happen if you put diesel in it. You won't get it all out. Don't do it.

You would be way better off installing a drain hose that screws into the pan like newer Mercruisers do.

 

[Alumarine]

Is the oil black on the dipstick or just browner/more golden?
Some oils are darker than others.

 

[hz293]

I'm going back over today. To look. Now that it's had time to drain back in the engine it will give me a better chance to look. It will be lighter out. I think I'll pass on the diesel flush. Thanks all.

 

[airshot]

As stated don't do the diesel flush....in the old days that was done but never all diesel fuel, just a quart or two added to motor oil depending on the capacity of the crank case. It does work great though, I have done it to many cars over the years but now I just change the oil regularly and don't have to worry about. Give your engine a good long run then change it again and you should be fine.

 

[Fishermark]

My current boat has a Mercruiser 3 liter in it. When I bought it it was in terrible shape and had been long neglected. I drained the oil (sludge). Then put a gallon of diesel in and ran the engine for about five minutes. Worked out great! That was a couple of years ago and the engine still runs fine. Keep in mind this was an old boat and simple 3 liter engine... not sure I would do it with a nicer set up... but it worked great for me. Just food for thought!

 

[Grub54891]

Well,I certainly would not run straight diesel, but a small amount don't hurt it.

 

[airshot]

Well, diesel fuel is a highly refined oil, perhaps a bit to thin, but that trick does work on badly sludged engines. A couple friends of mine also uses ATF and does the same thing. The ATF does cause the seals to swell and can and has stopped some seal leaks in the past. ATF has a higher detergent content than regular motor oil. I have used that in small engines with great success.

 

[stonyloam]

Jeeze... If you are that worried about it, pull the valve cover and take a look at the rocker arms, if they are clean, don't worry about it. If you are STILL worried just run it for a half hour or so and change the oil and filter again. I would never run diesel in my engine, it is a fuel, not a lubricant. Chances are there were an ounce or two of old oil left in the engine that mixed with the new oil, like Bruce suggested.