Pre-filling oil filter

walleye

I know there is a debate generally on the need to charge an oil filter with oil before installing a new one. On automobiles anyway. Of course I'm not certain how one could pre-fill on my 5.0s since the filters are upside down. And I'm guessing other Merc models are the same? So...thoughts on this debate and whether it is even doable with the positioning of Merc oil filters? I've never pre-filled my filters before but curious about others. 

mattie

Can't see why not. Maybe just pour enough oil in the filter to saturate the media. Think it would be good practice regardless. In past, I've filled new filters half way with fresh oil - virtually all the oil will be soaked up with nothing left to spill after 5 min or so.

jme097

^Bingo lol

craigswardmtb

Good luck with the mess it would likely create seeing its inverted.  I don't do it.

Handymans342

So, do the Merc filters have a check valve? My filters hold 1.5 qts. 

partlowr

mattie said:

Can't see why not. Maybe just pour enough oil in the filter to saturate the media. Think it would be good practice regardless. In past, I've filled new filters half way with fresh oil - virtually all the oil will be soaked up with nothing left to spill after 5 min or so.

You are 100% correct, the media needs to be saturated before it allows oil to pass through it. If you throw on a new dry filter and then fire up your engine it will take a little while longer for the oil to pass through the dry filter.

So even on an upside down mounted filter you should fill it with oil, let it sit and saturate a few minutes, dump out the oil and then install the filter that way the filter media is prepped.

212rowboat

ehh....

here comes one of those infamous winded responses...

*popular opinion that I subscribe to is that engine oil is best drained when warm, to excite the particulates held in suspension and to promote more out faster... makes good sense, no? 

*shear strength of oil is described as it's ability to adhere to hard parts while resting or in operation. it's what fills the tiny voids between moving parts, allowing the parts constant low friction and consistent tension and disallowing hot spots to form, as the oil is exchanged while the engine is running.  While it's not running, shear strength allows exposed metals to be treated against contaminants adhering to them, and this is an important aspect of Marine graded oils. 

*a lot if not most engine wear occurs in the seconds an engine is started to when it generates the oil pressure needed, sending it to the places it ought to go.

*an unprimed filter has to be primed by the oil pump before oil heads out to do what engine oil does....... unless:

unless you change oil and filter on a warm engine... and the reason why is the shear properties of the oil, which are adhering to the metals and inside the tiny gaps and protecting the moving parts in the few seconds it takes for the engine to build oil pressure, and then the few seconds more it takes for the filter to be primed. 

so.... if you change your oil the poplar opinion way, by warming it up first, there is little reason to concern about pre filling the filter.  

make sense? 

Handymans342

yes plus synthetic helps too

Michael T

It certainly used to be common practice for custom engine builders to advocate filling oil filters whether or not the oil had been warmed which it should be anyway for the reasons Drew has stated above.  The reasoning was that the oil would arrive at the newly changed oil filter with enough force to dislodge particles of its media or even damage it -  hence the recommendation to pre-fill the filter with oil. Pictures of damaged oil filters were shown as part of that discussion. I always pre-filled my oil filters.  It has been written that newer oil filters,  at least quality ones, are sufficiently robust to take a flood of oil. That aside I cling to my old habit and pre-filled my filters a bit -  not too much though -  as they are remote units and are "upside down". I think this is more of a personal opinion/choice discussion? 

Handymans342

If they are upside down would they not drain out when the engine is off? Unless they have an internal check valve

Michael T

Yes Steve,  but IMO that us not the thrust of the thread.  What I believe being discussed is the pre-filling of old filters after an oil change.  After that the oil filter still remains saturated with oil. Drained to some extent yes,  but still saturated. In the "old days"  some advocated cranking the engine to pre-charge an oil filter before starting the engine.  This never made sense to me because at least with carbed (non fuel injected engines)  that would dump unburned fuel into the cylinders,  that could potentially wash past the rings thereby diluting the oil. 

Black_Diamond

You could always add a pre-luber system. 

Michael T

I had one on  454, it worked really well. It was easy to install and not too expensive.