Oil Level and Contamination

[79sunrunner]

I was speaking with a Caterpillar mechanic instructor( I want to apply this to normal cars as well) the other day and he had some strange recommendations. For oil level seen through the dipstick
1) check when cold
2) if the oil level appears in the operating range (even a little above the lower mark) DO NOT ADD OIL (2006 Mustang manual states this as well)
3) when it does fall below minimum, add the appropriate amount to maximum level.
His reasoning was simple. Caterpillar is picky about oil contamination, and believes maintaining the oil level at the higher marks add more contamination as well. Apparently, fresh oil from an unopened oil bottle is "unfiltered" and is discouraged from being used. From my own assumptions, industrial machinery operates in hostile environments, and won't a low oil level raise the overall oil temperature? And as for "dirty" new oil, Caterpillar recommends that you DO NOT prefill an oil filter. their reasoning was to not add unfiltered oil in the engine. I can see this on small automotive filters, but doesn't some industrial filters carry vast amounts of oil? Wouldn't this cause dry starts? I know Cat is industrial, but their engines are not much different than ours as far as pistons and cams go, not diesel vs petrol What are your thoughts?

 

[Quattro Pete]

Some head-scratching comments, indeed.

Originally Posted By: 79sunrunner
Apparently, fresh oil from an unopened oil bottle is "unfiltered" and is discouraged from being used.

Even if so, it will only take a few seconds for it to circulate and eventually get filtered.

Besides, VOA samples normally show no contaminants, so what exactly needs to be filtered?

Adding fresh oil boosts the additive level which helps fight acidity.

Quote:

And as for "dirty" new oil, Caterpillar recommends that you DO NOT prefill an oil filter. their reasoning was to not add unfiltered oil in the engine.

So, you've just added 5 or 6 quarts of "dirty" new oil as part of an oil change. Is another 1/4 quart or less poured into the filter really going to make much difference?

With that said, I never prefill oil filters, but not because I think it adds more "dirty" new oil.

 

[Kruse]

It's been about 5-6 years ago, but I also read from a Caterpillar paper not to add oil to a new filter. Their reasoning was the oil poured inside an oil filter is not filtered or had the possibility of getting dirt in the oil.

 

[79sunrunner]

I prefill mine, simply because that's what Bernard Juchli does haha. The filters (I also posted this in the industrial section for the "big" filters" and those can hold around a gallon on their filters.) I wonder how long a unfilled filter would take to fill after an oil change?

 

[simple_gifts]

Im thinking all these recommendations are for ease of maintenance and minimization of error.

Between the lines = chance of overfill
fill filter = chance of contamination.

A running engine with requisite oil (between the lines) doesn't have problems; it is when someone gets their mitts on it the chance for error is greatly increased. (do we have to post the links to the threads right here on bitog?)

edit:It is unlikely a low(er) oil condition would greatly enhance oil temps to the point of being dangerous; they wouldn't design it that way. We are talking huge sump size, not an Xterra. jmo.

 

[toneydoc]

Well I always fill my filters that mount vertically. My Jeep filter mounts horizontally and I put some oil in it to get it started as well. And I tend to keep my oil level at full mark on dipstick. I tend to think I keep oil additives fresher and less chance of going below decent level. And when I change oil, I do not care if it splashes around some before being filtered. I am confident the oil company did this as I only buy name brand oils and keep them in covered original containers until use.

 

[Danh]

While these are theoretically interesting points for car owners to consider, I think environment is the big difference. Cat engines at worksite are in a very dusty, gritty environment, and any top-up oil is, too. I can see a desire to keep the engine as buttoned-up as possible, but this hardly applies to one's attached garage.

The oil filter pre-fill issue is an issue, just not a very big one. It's true that oil used to profile a filter will hit the bearings in an unfiltered state. But as has been pointed out, virgin oil is really contaminant free for us. On the other hand, in a Cat environment with grit everywhere and oil containers that may have been opened and shut a few times...

 

[Eddie]

I believe simple_gifts has the correct reasoning. Oil levels between the add and max are the safest oil levels for this engine. Why try to fix what is good? Ed

 

[KCJeep]

I can see grit in new oil at a construction site, totally different environment then your typical BITOG'ers driveway.

I no longer pre-fill filters but I keep my oil at the top, but not overfull. I can see no advantage or disadvantage to running between the lines, and again on a work site I could see the potential for grit getting into the engine while doing a top off that wasn't really needed. So it makes sense.

 

[KrisZ]

Originally Posted By: simple_gifts
Im thinking all these recommendations are for ease of maintenance and minimization of error.

Between the lines = chance of overfill
fill filter = chance of contamination.



Bingo!
Heavy duty equipment is filthy. Service is never just an oil change, but a bunch of other work that require the tech to crawl all around the machine. By the time he's done, he's covered in mud, grease, sand etc. so chances of him contaminating the oil are very high, much higher than in a jiffy lube type environment.

This is just but one more example why heavy duty machinery cannot be directly compared to light duty automotive cars and trucks.

 

[uart]

Originally Posted By: 79sunrunner
I was speaking with a Caterpillar mechanic instructor( I want to apply this to normal cars as well) the other day and he had some strange recommendations. For oil level seen through the dipstick
1) check when cold
2) if the oil level appears in the operating range (even a little above the lower mark) DO NOT ADD OIL (2006 Mustang manual states this as well)
3) when it does fall below minimum, add the appropriate amount to maximum level.


In my opinion this just for simplicity and pragmatism. In other words, if it aint broke, don't fix it.

 

[supercity]

This is the dip stick from a 1996 Ford Falcon. They just dont want you to overfill the thing. Once you get to the top of the "add" zone, adding 1L will fill it. It's no surprise 1L botles of oil are the smallest size you can buy at all service stations here.