Quote:
Originally Posted by OM617YOTA
Glad you got her going again.
Just an FYI, prefilling fuel filters is no longer recommended best practice. Better to let the priming system fill the filter, so that all the fuel that gets to the clean side of the filter was filtered fuel. Even "clean" diesel is still much dirtier than fuel that's gone through your fuel filters.
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His engine does not have a priming system. All it has is an air bleed within the Fuel Pressure Relief Valve. However, if a gulp of air from the Fuel Filter makes it into the Fuel Injection Pump housing and that Air gets into the Fuel Injection Hard Lines you are going to put a lot of stress on your Starter and Battery trying to get the air out of it.
That is helped/reduced somewhat if you loosen the Fuel Injection Hard Line Nuts at the injectors and give the Air an escape route.
Filling the Fuel Filter has been around before I started being a Diesel Mechanic back in 1975. So it is a well known practice. If it did any damage the practice would have been stopped long ago.
But like anything else people not doing their job a making sure clean diesel fuel with no other contaminants like dirt get into the Filter while they are filling it and installing it are to blame.
Some Companies like CAT tell you not to pre-fill there filters unless you use there special funnel that has a filter element in it. Cats also usually have a hand primer. You stick the funnel inside of the Filter properly and fill the filter.
Additionally there is a lot of engines out there with no sort of manual primer.
The issue cries for the use of common sense.
I was also briefly a Wheeled Vehicle Mechanic in the US Army Reserve. The diesel trucks had 2 Fuel Filters that were 2 quarts each.
That is one gallon of Air that has to be removed if someone is lazy and installs new filters dry. And soldiers are lazy and yes the vehicle won't start for some times a battery killing long time.
Just for a story in the above case what you should do is change one filter fill the filter with clean diesel then start and run the Engine. Then you go to the other Filter and again fill it with clean diesel and start and run the engine. It can be messy but that is the least troublesome way to do it.
The same way with the Mercedes. Change the pre-filter first and start and run the engine and then do the spin-on filter and fill it if you can do that. If you have one use the hand primer even if you filled the filter and if the filter was installed dry use the hand primer until you think it is filled and then use the hand primer some more because that is easier then having to bleed the air out of the Hard LInes.