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

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Always inspect the seals

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Soon after I bought my first Dodge-Cummins and joined TDR someone started a thread that contained a very valuable tip/warning that may have prevented me and many others from buying a new engine. I ALWAYS remember it when doing my own oil change but have not seen it mentioned in a long time. It's worth reminding everyone of here.

Prefilling an engine oil filter may (or may not be) a good idea for caring for an engine.

It seems that back in the '90s Cummins/Dodge and lots of unhappy owners experienced failed engines shortly after performing or having an oil change performed. Cummins disassembled a few warranty claim engines (and rejected the warranty claim) because a tiny sliver of aluminum was found blocking a piston cooling jet hole under the piston.

The cause was a tiny scrap of aluminum from the seal on top of the gallon jug of fresh engine oil. Apparently it happened many times. An owner, in a hurry, would puncture or tear the aluminum seal away and hurriedly pour fresh oil into the center of the new oil filter.

Oil poured into the center chamber of the oil filter bypasses the filter element and the engine oil pump takes a suction in the center chamber of the oil filter. If that fresh oil contains a tiny sliver of aluminum oil jug seal it will be introduced directly into the engine's oil supply and pumped straight through the engine.

Cummins engines have a tiny hole in the piston structure (haven't seen it, just read about it) that allows engine oil flow for piston cooling. A sliver of aluminum will plug the cooling hole. The first time the driver puts his foot in his Dodge to pull a grade or tow his trailer after an oil change he overheats and melts a piston and wipes out an expensive engine.

Not long after I read that valuable tip on TDR and old friend was visiting, pulling his fiver with his 7. 3 Powerstroke Ford and wanted to change the oil while he was here. To demonstate the warning, I held a paint filter in place for him to pour fresh engine oil from the gallon jug into his oil filter. To our surprise, we trapped a tiny sliver of aluminum seal in the paint filter from the new oil jug he had opened.

Do-it-yourself oil changers beware. Prelubing your oil filter is considered a wise practice for avoiding dry start-ups but it you accidentally allow a sliver of aluminum oil jug seal to drop into the jug and pour it into the center chamber of your oil filter while pre-filling the filter with fresh oil you could destroy a new engine.
 
I don't prefill the oil filter when I change the engine oil. The engine isn't dry and the oil pump will quickly fill the filter and build oil pressure when it's started.



I've seen hundreds of Cummins engines with the pan removed after the crankcase is drained. The engine will drip oil for days.



Bill
 
Good post. I just prefilled mine two days ago when I did the oil change,but am always very careful to make sure the seal is fully removed. Delo gallon jugs have a plastic tab on top and the seal comes off cleanly. I remember that article in the TDR. It warned about Fram filters also.
 
It's just not slivers of aluminum. Sometimes there are little chunks of plastic from when the jug is made. Don't prefill the filter.
 
Thanks for the info Harvey! I guess that's just one more thing to watch out for... I use Delvac but I don't like the thought of a piece of plastic getting in there!!
 
I think Bill Stockard's advice above (as always) is probably the best to follow. I've learned many things from Bill over the years since I bought my first Dodge-Cummins and have never found him wrong.

I do prefill sometimes but always worry about it when I do. Based on his dripping for days story I think I'll just quit the bother and risk of prefilling the filter.
 
I understand the rationale behind the cautions of missing a piece of aluminum foil or a small piece of plastic from the oil jub... but... what about using the paint strainer (already mentioned) just as insurance to eliminate the worry against this? Might take a while for the thick 30W oil to run through. . but at least it would solve the problem would it not? I would feel better having the oil filter full when replacing it... just seems to make sense to me... needed or not.
 
That's a new one on me and I have been working on large diesels for close to 35 years in the testing and research and development field. You need to fill the oil filter before installing it. Trust me on this one. If you need to you can filter the oil thru a nylon stocking or a paint filter but this step needs to be done.
 
Thanks for the great advice. I'll remember this when I change oil not only in the Cummins but also in my gassers too!
 
I usually plug the hole in the middle of the filter and then fill it. That should prevent any plastic or metal from entering the engine. Ed B
 
The engine isn't dry and the oil pump will quickly fill the filter and build oil pressure when it's started.



Yep. I just changed my oil, didn't prefill and the oil psi came up faster than it does when its 20* outside. (I have a real gauge on the drivers side, long after the filter).
 
It's just not slivers of aluminum. Sometimes there are little chunks of plastic from when the jug is made. Don't prefill the filter.
Interesting point, I have always prefilled once I knew for sure I got all of the seal off but never gave thought to manufacturing debris.

I am not 70 like blackbear but have been at it since 1977 with no problems but once is once too many.
 
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so when you pour oil into the valve cover and it makes it way down to the pan, are there no places the oil can go that can trap foil or plastic pieces and cause damage before it ever hits the pump and filter?
 
I don't know who is right or wrong on this. But here is something for thought. Where do you think that QUART of air goes that's in the oil filter. It has to go through the engine to get out. Have you ever seen what air bubbles can do to bearings. I have and if it's done enough times the bearing has pin holes and dents in it. That Babit layer on the face of a bearing is soft and an air bubble explodes when compressed and surrounded by liquid. I have always prefilled my filters (48 years) and never had a problem. Besides I don't like the rattles and knocking the engine makes before pressure comes up. So I will always prefill and be careful doing it!
 
so when you pour oil into the valve cover and it makes it way down to the pan, are there no places the oil can go that can trap foil or plastic pieces and cause damage before it ever hits the pump and filter?



I think the biggest issue is the nozzle on the piston coolers. Anywhere else can be bad, but not AS bad... While I haven't had the valve cover off on the 5. 9, on other inline motors I have worked on there is a straight shot to the oil pan under the oil fill cap.
 
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