Oil Filters

Well, no replies..... Next question then. What test can be done on the filter from my car (92 Accord LX, 225,000 mi) to see what is trapped in there after 5000 miles? bob

Get a hacksaw and cut the filter in half - it's not too hard, they are made of pretty thin metal. Look closely at the internals and you should be able to pick out some debris, unless your engine is really clean, not too new, not too old, etc. A new engine will still be 'breaking in' and could have more wear particles in the oil, whereas an old engine will be starting to wear out and could have more wear particles in the oil. If you do a lot of city driving, you will likely have dirty oil. If you drive 40k miles /yr like I do, your oil will likely be quite clean if/when you change if by the recommended schedule. Just stuff to keep in mind...

Just what are you hoping to see? The average OEM oil filter will remove particles as small as 10 microns (maybe even a little smaller). A micron is equal to 0.0000393700787", so 10 microns is equal to about 0.000394", or 4 / 10,000ths of an inch. I guess if you have a microscope you could prove that the smallest particles are being removed. If you can see any particles with a visual inspection, you probably have problems.

Doug

I think the real question is, "what can get into my oil that needs to be filtered out?" Cars don't use breather caps any more so we shouldn't have to worry about unfiltered air with grit being pulled into the engine any more, but oil changes and fills are not always done in clean room conditions. The towel we wipe the dipstick with at the gas station isn't guaranteed free of grit or dust. Okay, so maybe contamination is rare, but when it occurs we sure don't want to pump abrasives into the close bearing surfaces of modern engines. The amount of grit doesn't even have to be visible to be a big issue.

On the original question, the filter size probably is determined by oil flow and filter geometry, and those are changing. The filter in our Toyota has (let's see if I can describe this) a half dozen lobes of pleated paper, so the pleats are at a right angle to standard filter designs. If you think of replacing the flat paper of each pleat in a normal filter with pleated paper, you get the picture.

Mike

Wear particles from the engine (anything that wears has to go somewhere), slight amounts of blow-by by-products (the rings do not make a 100% perfect seal) and by-products from the decomposition of the oil itself.

A well maintained engine in it's mid-life stage probably leaves very little in the oil filter, hence the small filter and every other oil change replacement recommendation on modern Hondas. Indeed things have changed a lot from the days when FL-1A size filters were the norm and needed changing every 3,000 miles.

If you have a well equipped analytical laboratory handy then you are all set to see what is really in your used filter. Otherwise, not much you can do on the cheap.

John

There has to be a lot of "whatever" on the filter element. Weigh a new filter. Now weigh a used filter, after you have drained the old oil out. I may not be able to detect what actually is on the filter element, but it has to be something that is not good to let through ?

You will see some debris - from the hacksaw cut :-] Greg.

Sure, so use a large pipe cutter.

Eric

That was going to be my suggestion. One could cut open a new oil filter, remove the element and weigh it, soak it in clean oil, and then drain it thoroughly. Now, take the used oil filter element and drain it. Weigh both filter elements and compare the difference. To compensate for inherent variability in the weights of the filter elements, it would be best to repeat the process several times and use the mean of your measurements for comparison.

Eric

All you need is a lab quality scale to measure accurately and some method to determine if the oil saturation changes with use.

Again, not a home project unless one has special equipment such as an analytic quality scale.

John

I thought there were folks who (1) changed the oil at x miles, left the old filter in for x more miles, then examined the oil; and (2) same thing, except the filter was replaced after the first x miles. In (1), the oil was dirtier.

"N.E.Ohio Bob" wrote

what is trapped

If I were you, I would never change the oil or filter. It is a waste of time and money.

Give it some time, and eventually your vehicle will start using oil, and at some point, you will be changing the oil VERY often by just adding new oil!

Think of the time you will save draining the old oil and changing the filter!

I smell an Infomercial there for a new Oil Reservoir like the washer tank. Just push a button and add a qt. of oil to the motor!

G-Man

I would hope the weight of debris trapped would be less than the variation among filters and variation in amount of oil retained.

Mike

The weight difference is quite a lot, hence my statement that there must be a lot of whatever trapped.

One of your earlier posts suggests that you were comparing the clean dry weight to the dirty oil soaked weight. This might lead to inconclusive results. That's why I suggested using a clean wet weight for comparison. I agree with the other posters that although it would be an interesting academic exercise, time might be better utilized in just changing the filter and forgetting about it. One thing to think about though is that manufacturers include a high pressure bypass valve in their filters. This valve diverts the oil flow in the filter bypassing the filtering element when the back pressure is too high. This likely occurs when the oil is cold and thick or when there's so much crud in the filtering element that it starts impeding the oil flow through the element. Bypassing the element in such cases at least prevents oil starvation in the engine.

Eric

OK, next time I change oil, I will do the "wet with oil" comparison. To eliminate oil filter waste, I will just fill the new oil filter all the way with new oil and then compare to the old one, all the way filled up with old oil. Will report back.

The trapped particles are metallic (mostly iron). The filter and the trapped particles can be washed and if the filter is cellulosic everything can be ashed, yielding metal oxides (iron oxide).

If the filter cannot be ashed (glass fiber filter) the metal particles are dissolved in acid and then heated to high temperatures, again yielding metal oxides (iron oxide).

It would be more accurate to thoroughly dry both elements (as in a low-temp oven), then weigh them. There may be different levels of absorption you're dealing with, not to mention the normal variance among filters to begin with...