Engine Flush

[Cary and Don]

We are going to do an oil change.  The oil in there now is of unknown age and really black.  Has anyone ever flushed the engine with something before pouring the really really expensive new oil in it?  It would be nice if the new oil looked like new oil when we are done.

Don and Cary
1973 05 Eagle
GMC 4107
Neoplan AN340

[Melbo]

When you change the oil in a diesel it never looks new once you start it up.  Oil in a diesel is ALWAYS black.  Just part of the charm of a diesel engine.

HTH

Melbo

[buswarrior]

If you are worried about it:

Change oil and filter, drive it 100 miles, then monitor oil via the dipstick.

If oil has gone dirty again, two choices:

Change the oil filter again and carry on.

Change the oil and filter on a shortened cycle until you get the colour you want.

a new to me old engine gets monitored and a short cycle oil and filter change.

happy coaching!
buswarrior

[TomC]

Detroit 2 strokes always get black quickly.  The way I tell if the oil is to carboned up and needs to be changed is to pull the dip stick and rub off some oil between two fingers. Rub the oil between your two fingers-if you can readily rub the black and see your skin again-it is still clean.  If you rub the oil and it stays black on your skin it's time to change it.  Good Luck, TomC

[Fred Mc]

A few years ago in an attempt to cure oil leaks I took the pan off my PD4106 and cleaned it as well a changed the oil and filter. Subsequent to that I left for California and about 100 miles from home I decided to stop at a rest stop and check the oil. It was at night so it was kinda dark and hard to see. I pulled out the dipstick and almost fainted as there was NO OIL ON THE DIPSTICK. Turns out that because I had cleaned the oil pan it was taking the new oil a long time to get black and although there WAS oil on the dipstick I  couldn't see it because it was still clear.

[Bill in KS]

I used to subscribe to the myth all diesel oil turns black the minute you start up the engine on a fresh change.   


Send me a PM, I'll be happy to share info on a great engine flush product.  A flush is a great idea to reduce the shock when you change oil brands plus your new oil depending on its additive package won't have to work so hard to clean up your motor. 

My cell is 417 439 5950

Bill in KS

[luvrbus]

Don, do you have a photo of which filter you have on the engine if you have the Thermatic style you need to toss it,I would not add anything to clean the engine just change the filter a couple of times between oil changes it will clear up if you have the full flow or bypass filter 

good luck

[JohnEd]

The oil in a D gets thicker as it gets used.  The soot does that.  D oil doesn't drain off the internal parts or empty the gallies as quickly as auto engines do.  Also, we are using 40 weight and that is flow challenged at any temp except HOT.  Even if you let it sit and drain for for hours you arew going to have a lot of the old oil sitting in there.  This IS NOT A PROBLEM, as far as I can tell.

NOW, I have always been a trifle anal about this topic.  At the oil change EVENT I add a gallon of kerosene to my "cold" 5 quart capacity crank case.  That brings the level up to at or near the crank.  I start and run the engine at "fast idle" for 15 minutes.  I then drain, remove the oil filter, and let it sit for an hour.  After installing the new filter and oil my oil shows transparent and stays that way for the first (almost) thousand miles.  I learned this from a Engineman Chief Petty Officer.

On engines in a used car I purchased I added an initial "twist".  Before adding the kerosene I would add a quart of methyl alcohol....laq thinner, to my COLD crankcase.  Then I would head for the freeway so I could run the engine at high rpm and heat the oil quickly.  As alcohol evaps at less than 180 the stuff would only be in the oil for 10 minutes of so.  This would dissolve the varnish and other hard deposits inside the engine and clean the EGR valve in the process of passing thru that item.  Once home I would add the kerosene, run, and drain.  I did this for ther 25 years I lived in SoCal and never had an engine failure.  The few I tore down to rebuild and blueprint (idle hands) were pristine clean inside.

Just my way...but based on results with many cars, it worked.  Thanks again Chief.

John

[luvrbus]

The problem with a DD 2 stroke is the oil galleys never drain so it turns black in a hurry till you get that part flushed I am sure some here have removed the bypass valves on the block inside the pan lot's of oil left there lol

good luck

[Cary and Don]

We have a V71 manual for GM buses. The filter looks like the one in the manual. It has an element that is installed from the bottom.  Not sure if that is the filter you are talking about.

Don and Cary
1973 05 Eagle
GMC 4107
Neoplan AN 340