Diesel in crankcase for a flush?
 

My boss told me one today, where you replace the oil in your crank case with diesel fuel, and then run it for 5 sedconds and it's supposed to flush the crank case and remove sludge and crap. I think it's BS. I'd approve a 20% replacement for a flush but not 100%.

No,No,No,No,No!
 

Not enough "Lubricity" in Diesel Fuel (Of any kind) to protect your engine's
bearing surfaces under load conditions.
Not Even the thought of a "Powered Revolution"!
You'll be Begging for trouble!

Disclaimer:Your Engine ,Your Pleasure!

Think about this though...We Pre-lube the Bearing surfaces of a New or Re-manned Engine with a special assembly lube to protect the Bearings from
damage,JUST UNTIL THE OIL PRESSURE COMES UP!

The Bearing surfaces "Ride" on a WAVE of Lubricating Oil.

I don't know if it's possible...BUT...
It would be funny as Hell if the Heat and Compression of the Loaded Bearing surfaces Ignited the Diesel being used as a "Cleaning" agent...That'd be a
real mess![Great idea for a "Mythbuster's" Episode]

A couple of sumps of Synthetic Oil will clean "all" the funk out of an Engine.

It's not a clogged up toilet is it? If you do regular changes with quality oil then there's no need to flush it. I'm changing the oil pan (PO had issues:() on our "new" 93 300D. Insides look as new, just the oil was black. Certainly no flush needed at 200K miles.

My first worry was fuel washing the bearings and the cylinder walls.
I was just thinking that flushing the engine and cleaning out the oil pan would be a good base line for a synthetic switch, then I don't have to worry about solids clogging the sump or whatever.

Ask him to demonstrate it on his car first. See what happens. :D

We seem obsessed with clean insides. Peak inside the valve cover first, see if you have anything to be concerned about before subjecting the engine to a colonoscopy. Remember Ano Gum to keep those other cheeks clean :D(thanks Monty Python!)

I learned this a couple of years back....

Changed the oil in my 117.968 to 5w50 synthetic from dino, and after a few months, my oil pressure was getting lower and lower when hot.

In the end, after checking everything else, I pulled out the oil filter, and it was nearly clogged! The synthetic oil had lifted all of the crud out of the engine and had plugged up the filter. After that, I changed the filter out every 1000 or so miles until the next oil change. All seems back to normal now.

"Old school" stuff. We used to pour in a quart of kerosene, ATF or diesel just before we did an oil change. We'd run the car/truck/tractor around the block and then drain the oil. Just makes the oil a little thinner and quicker to drain. Never seemed to do any harm and I doubt it ever did any good but "ol' Herbie", who lives over there on yonder hill, who has been working on engines since Barney Oldfield days, swears by it.:D

Probably a hangover from the pre '50's cars which didn't have oil filters.

You can use BG Engine Purge, but at your own discretion... it works well in motors to help remove the oil crud & deposits -can be used in diesel engines & should be available from your local indy M-B shop

http://www.bgprod.com/products/engineoil.html

BG 120
BG Engine Purge
BG Engine Purge is not an ordinary engine flush. It is an effective blend of solvents and dispersants which will quickly and safely remove accumulated sludge and other deposits from the engine. It can actually restore compression by removing soot and deposits from around the rings; hence, the compression rings seal in compression gases. BG Engine Purge does not contain harmful chlorinated solvents. It may be used in gasoline, diesel and rotary engines.
Part No. 120 32 oz. (946 mL) bottle

I've had great luck with Auto-RX. My '93 300CE had a crudded up oil system. The filter was black and SOLID with sludge when I first got the car. I followed their instructions and it cleaned it up beautifully. Even stopped a couple of leaks. I now add 3 oz per oil change.

http://www.auto-rx.com/index.html

Anziani
'93 300CE 180K
'95 E420 117K

Only ever heard of diesel being used to free a seized engine... bearing in mind that a kill or cure option is better than a total loss.
Engine was a rolls royce b80 military in a Saracen armoured car. Only way to get it out was to completely dismantle it or cut the hull open, and electric weld it back afterward. On an eleven ton armoured hull it could have been expensive on a tight budget. So all eight cylinders were fuel filled with the plugs out, a starting handle inserted and a jack applied to bring pressure to bear and left to stand for a month.
For reference. When pressing starter button with batteries connected make sure no-one is standing next to the engine downwind on the spark plug side as dry cleaning bills are an additional expense.
...heaven help them if they are smoking...
Last heard, engine still running, ten years on.

Al