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Oil Changes

May 08, 2010, 10:54:30 am

While at a local trucks parts store a discussion ensued on the subject of oil changes.  The question was posed " Why do you prefill an oil filter " ?  Most common answer was " Because we have always done it that way " !
Group was pretty evenly split on whether it was necessary to prefill a filter.  Argument on one side was that pan was full of oil and after first rotation or so when starting the filter would fill.  Other side was if not prefilled engine will not have oil pressure immediately on startup.
Both these seem to be valid points but I am now curious as to whether there is any valid reason for either method.
Just for the sake of argument what do others think ?  I cannot recall seeing a specific procedure from the engine manufacturers but I may be wrong.
I for one would find an oil change much easier on my Cummins if dry filter could be used mainly due to weight while reaching overhead and mess if filter is overfilled or tilted.
Curious minds want to know !!!!
Gary B
95 U280

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Re: Oil Changes

Reply #1 – May 08, 2010, 11:53:50 am

In a cummins manual I found this " Fill the oil filter with clean lubricating oil. The lack of lubrication during the delay until the filter is pumped full of oil is harmful to the engine"

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Re: Oil Changes

Reply #2 – May 08, 2010, 08:02:36 pm

Barry,  After your reply I searched and you are right, Cummins recommends that you prefill the filter.  Only goes to show that the old RTFM, holds true.
Gary B
95 U280

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Re: Oil Changes

Reply #3 – June 07, 2010, 11:31:35 am

I always add oil to the filter if I can.  A number of cars I have worked on have horizontal filters which make that impossible.  Those filters are much smaller however.  One thing I noticed was that I would fill up the filter and shortly I would have to add more oil.  My guess is the filter paper was absorbing the oil.  You could possibly avoid filling the filters by using a pre-lube system.

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Re: Oil Changes

Reply #4 – June 08, 2010, 08:15:23 am

Gary,

Every Fleetguard oil filter has the installation instructions printed on the side, including pre-filling with oil.  I keep adding oil until the oil level in the filter doesn't drop.

Regards,

Brett

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Re: Oil Changes

Reply #5 – June 08, 2010, 09:06:57 am

If you do pre-fill the oil filter, there is a right and wrong way to do it.

The small outer holes are the INLETS, the large center hole the OUTLET. 

Pour all the oil in the small holes.  Any oil that gets in the (much easier to hit) large center hole will go to your engine UNFILTERED.  Do not assume there are no particulates in new oil (ask any Petroleum Products Engineer.

Many go to a hardware store and find a short pipe that threads into the center hole while pre-filling to keep oil from the OUTLET hole.

BTW, Caterpillar recommends AGAINST pre-filling filters for just this reason-- fear of particulates in oil passing directly into bearing areas.

Brett Wolfe

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Re: Oil Changes

Reply #6 – June 08, 2010, 02:38:47 pm

Brett,  The little very dim light just came on,  Apparently in the original discussion in the parts store the group was discussing apples and oranges.  I ASSumed that all of us were discussing Cummins and it never occurred to me that anyone would drive a CAT.  Since this group was made up of dump truckers and dirt movers there were both Cummins and Cats in the store, mainly Cats.  My lack of knowledge of Cat oil change procedures mad me prejudge what I was hearing.  DUH

I use a short piece of threaded PVC to fill the filter, its light and easy to store and clean.

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Re: Oil Changes

Reply #7 – July 27, 2017, 11:30:24 pm

Have seen many natural gas Cats start without filling the filter,once you hear the drive train rattle and shake you'll always fill the filter.

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Re: Oil Changes

Reply #8 – July 28, 2017, 01:36:30 pm

I have always filled my oil filters on my over the road diesel trucks. The thought of running the engine dry until the big filter fills itself is one I would never get used to. I do it with the smaller filters that are on my 3208 as well. I can think of several reasons for doing it but zero reasons not to. There is no way that 1 or 2 engine rotations can fill a small filter, let alone the big ones.

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