Warning: Prefilling An Oil Filter Can Be Dangerous To Your Engine

[mwilson]

... and you just pre-filled your fuel filter with unfiltered fuel! It probably didn't matter with the old PT systems. :-laf



Bill

Those old PT pumps were not fussy at all.



Also at -10 below with one shot at reviving the engine and one shot sticking your hand into the cold diesel fuel to fill the filter we didn't care as long as the old piece of cast iron would start again.



Extreme cold will quickly bring on a temporary lowering of one's standards.....



Mike.

 

[NIsaacs]

... and you just pre-filled your fuel filter with unfiltered fuel!



Not if ya stick your finger in the threaded hole and let it fill like it filters... . that sounds kinda wrong.....



Nick

 

[Bill Stockard]

... and you just pre-filled your fuel filter with unfiltered fuel!



Not if ya stick your finger in the threaded hole and let it fill like it filters... . that sounds kinda wrong.....



Nick

I was waiting to see if you knew to do that... :-laf I've watched many diesel mechanics do that... some didn't close off the center hole and some did. Like Mike wrote above the PT systems were very forgiving. All the filter needed to do was screen out the big rocks and sticks.



Mike, I asked Nick, but he didn't answer. Did you ever prefill the fuel filter with B-12 Chemtool? "Mechanic in a can":-laf:-laf



Bill

 

[mwilson]

I was waiting to see if you knew to do that... :-laf I've watched many diesel mechanics do that... some didn't close off the center hole and some did. Like Mike wrote above the PT systems were very forgiving. All the filter needed to do was screen out the big rocks and sticks.



Mike, I asked Nick, but he didn't answer. Did you ever prefill the fuel filter with B-12 Chemtool? "Mechanic in a can":-laf:-laf



Bill

No, never heard of the stuff until just now.



Just did a quick search on it and I think that all Hell would break loose when that hit the injectors and ignited.....



There are several memorable mornings from the past when a quart of it looks like it would have come in handy... .....



Mike.

 

[NIsaacs]

I don't know what it is either, is it like gas and a styrofoam cup??



Nick

 

[Bill Stockard]

No, never heard of the stuff until just now.



Just did a quick search on it and I think that all Hell would break loose when that hit the injectors and ignited.....



There are several memorable mornings from the past when a quart of it looks like it would have come in handy... .....



Mike.

Yep, it makes lots of noise, clattering, clanking, smoke, and burning pieces of carbon blowing out the exhaust pipe and floating down... quite a scene. :-laf:-laf



We had a service manager over our truck shop back in the late 60s who thought it was a good way to clean the injectors. I don't know about the injectors, but it broke loose a lot of carbon. I called it "a mechanic in a can". I'd never let anyone do that to my old PT Cummins, if I owned one.



Bill

 

[Deathrowdave]

Been working with Large White industrial NG and Diesel for years (30+) . Trust me there is major wear brfore the filter fills . Needs to be filled before starting. Cuold start and stop a few times fast to fill filter . Large engines have a hand pump to prelube before starting.

 

[AH64ID]

How can there be major wear when the filter fills within seconds, and faster than cold oil on a cold day?

 

[Deathrowdave]

The position that your filter is in it remains full after started . With gravity it is impossible to drain back. Have you ever noticed that on removal that there is a small amount of oil leakage? If it is not a problem why did they mount it so it has no drain back FILTER FULL all the time. Why would you want to pump a quart and half of oil into the filter before the engine gets any lube. Watch the gauge with a dry filter . How long before oil pressure shows on the gauge . If you don't mind get a filter with a drain valve and drain contents every time before starting. No big deal if you are OK with it , it is your equipment good luck.

 

[HBarlow]

The position that your filter is in it remains full after started . With gravity it is impossible to drain back. Have you ever noticed that on removal that there is a small amount of oil leakage? If it is not a problem why did they mount it so it has no drain back FILTER FULL all the time. Why would you want to pump a quart and half of oil into the filter before the engine gets any lube. Watch the gauge with a dry filter . How long before oil pressure shows on the gauge . If you don't mind get a filter with a drain valve and drain contents every time before starting. No big deal if you are OK with it , it is your equipment good luck.

Watching the oil pressure gauge may make you feel better but it only shows a simulated reading. It does not read actual oil pressure. If there is any pressure above a low minimum figure, I don't remember what it is, the computer simulates oil pressure and provides that artificial pressure as a small mini or micro volt signal to the gauge.

 

[DJW]

I have a Clark forklift the two filters, one engine oil and hydraulic oil, both have the open end down, so filters go on dry. I believe oil for engines for the most part is drawn from the lower part of the sump, so on a Cummins that's around 10 quarts plenty, of time for the filter to fill and become pressurized. Its the return oil that fills the filter after passage through the engine. Harley Davidson as also many European motorcycles did have dry sumps, the oil is pumped from the supply tank through the engine and scavenged back to the oil tank through a filter. The scavenged side of the pump is greater than the supply side to ensure the sump does not collect oil. Some Harley purists would disconnect the return oil pipe from the oil tank and run the engine keeping the oil tank near capacity until the return oil ran clear.

 

[Deathrowdave]

Dudes, this is getting no where Harley Davidson engines have roller bearings on the crankshaft. Very small amount of oil need to lube bearings , normal oil pressure at idle is 0 psig. I have been a certified Harley Mechanic for years . Completely different than insert bearings on a Cummins engine. This is the reason that I don't normally deal with forums . Better things to do than argue!! Do what you feel comfortable with and carry on !!!

 

[dresslered]

Wow, over 12,000 views on this subject! May as well add my 2-cents. Either way works just fine. I always pre-fill mine (without letting contaminants enter) but it's your choice. You're going to find that a lot more things will break on this truck before the engine prematurely wears out.

 

[BIGNASTY]

I dont pre fill I just put everything together and turn on key and let the Pre luber fill the thing.

 

[AH64ID]

I dont pre fill I just put everything together and turn on key and let the Pre luber fill the thing.

But that will be old yucky oil :-laf

 

[BIGNASTY]

How do you figure that? I change the oil spin on the filter and turn on the key. Oil is sucked up form the pan (clean oil) ran Thu the motor to build pressure along with filling the filters as I have more than 1 when oil pressure is built showing on the truck gauge fire it off done every time I start the motor ( NO DRY STARTS WITH PRE LUBER). Without the filling of the filters of course because they are filled from the previous start just like the rest of the motors. In fact I don't even have to pull the pan plug to drain the oil just disconnect the one end of the hose and turn on the key. I don't but I could if I want to. Could even add an additional filter from the Pre Luber pump to motor to filter oil but I think the Donaldson along with the FS 2500 is good enough on engine oil filtration YES?

 

[AH64ID]

So you have an electric pre-luber, all the ones I have ever seen or worked with are accumulators that store oil when the engine is running, and use the engines oil pressure to create the pre-lube, thus the oil in the luber would be the pre-change oil.

If you use good oil there aren't any dry starts even without one. I also don't think there is a check valve in the system, so there isn't anything keeping the oil from going backwards thru the pump as it would be the path of least resistance vs the bearings.

Any pics of your setup? Where does it put oil into the system at? If it's the port in the top of the oil filter housing that's filtered oil, so the pre-luber would be pushing unfiltered oil thru everything, and reverse flushing the oil filter at every start.

 

[BIGNASTY]

So you have an electric pre-luber, all the ones I have ever seen or worked with are accumulators that store oil when the engine is running, and use the engines oil pressure to create the pre-lube, thus the oil in the luber would be the pre-change oil.



If you use good oil there aren't any dry starts even without one. I also don't think there is a check valve in the system, so there isn't anything keeping the oil from going backwards thru the pump as it would be the path of least resistance vs the bearings.



Any pics of your setup? Where does it put oil into the system at? If it's the port in the top of the oil filter housing that's filtered oil, so the pre-luber would be pushing unfiltered oil thru everything, and reverse flushing the oil filter at every start.

I cant find the website but took copies off the instructions that I got with it until I can find site I think that Hughes Net is going nuts today cant get anyplace at times. The black box in the center pic is the pre and post timer for the system. I don't have to leave the truck running the pump will circulate the oil . The way I found this was I bought a BIG truck used and it had one on it and had a fresh in-frame rebuild on the motor . I ran the truck for about a hundred thousand miles and went to roll in rods and mains and when I pull the caps and the bearings they looked A WHOLE LOT BETTER than without the pre lube pump that system didnt have the timer on it this one does . Found another one that has the elect. pump while looking for mine. Wife got off of the phone with Hughes Net some kind of solar flares happening. in other words they haven't a clue. I would have to ask the guy at Cal Pac Cummins in Ca where he tapped the oil back into the motor he did the install along with installing one on his. I do check it when I change oil by pulling the return on the FS2500 and turn the key and wait until it starts flowing out of the return to the motor. The drawing pic shows it going back to the sender but for some reason I don't think that is how he plumbed it but not sure. The tap on the top of the OEM filter housing is where my FS2500 taps in then into the motor so my Donaldson filtered oil is going bypassed into a 3 micron absolute bypass then into the motor. JMO but if your not running a Bypass filter with a bunch better filtration than just the best Donaldson YOUR RUNNING LIQUID SAND FOR MOTOR OIL

SOS Automotive

 

[AH64ID]

Hadn't seen those before. It still looks like it's pumping unfiltered oil into the motor and I am not sure I like that idea, considering that's why many people don't prefill their filters. Your FS2500 should be dumping oil back to the crankcase, not into the motor. I would be interested in pics of where it dumps into, but like I mentioned I am not sure you can avoid back flushing the oil filter every time it runs (which pushes the contaminates back into the oil pan, where the pre-luber will push them to the block). I really see one of these having the ability to do a lot more harm than good.

The Best Donaldson is 15um absolute, the OEM filter is 35um absolute, not sure I would call that liquid sand, considering how many hundreds of thousands of miles these motors go with OEM filtration, that being said I run the Donaldson and 2um Amsoil Bypass.

 

[BIGNASTY]

FS dumps back into the rocker cover drill a hole and tap it. Or you can get one of the oil fill caps with the tap in the center I would have used one of those but didnt know about them at the time. Have a call in to buddy at Cummins HE ACTUALLY HAS TO WORK FOR A LIVING (poor guy) and hasnt called back yet as to where the pressure side of the pre lube goes.