Engine protection with shorter oil filter change interval ?

livi · 07-20-2006, 01:15 AM

I kneeuw... its been debated to death. But since the oil technology keeps improving and a modern high quality oil probably retains its protective qualities with normal change intervals - would an intermediate filter change gain any extra protection ? (I know - punctuation!)

There is a never ending debate on which oil has the better properties. With the short intervals most of us have - arguably any modern oil would do. At least for street use.

So, for that cheap $10, would an in between filter change do any significant difference - at least in the long run ? Picking up a few more nasty particles and sludge.

Reason for the topic as above plus the fact that I have run out of DIY projects. I have come to appreciate wrenching so much and suddenly there is only driving left.

Bill Verburg · Bill Verburg's Garage

Oil needs to be changed more because the additive package is used up and or condensates accumulate. More frequent filter changes won't address either issue.

Long drives will address the condensate issue, so if you want to do something good for your car take it out frequently for a long drive.

Kroggers · Kroggers's Garage

Quote:

Originally posted by livi
Reason for the topic as above plus the fact that I have run out of DIY projects. I have come to appreciate wrenching so much and suddenly there is only driving left.

So drive the car up here and help me out with my long project list

cnavarro · 07-20-2006, 06:03 AM

I use a very good synthetic with a high TBN and use the mobil 1 filters, as they have the best filtration of any filter you can get easily (autozone, etc) and I change the filter in-between oil changes. Can't hurt. Just spend the money and use the best filter possible i.e. a filter with synthetic media.

livi · 07-21-2006, 12:50 AM

Right. Thanks!

Then, Bill, I am doing what I can cause me regular drives are never shorter than 20 miles - frequently the double.

I see your point there, Pål.

cnavarro, have you ever split up the used filter to see how much sludge its accumulated during a season ? Would be interesting to see if it still looks brand new after say 3k miles.

Oh well, I suppose I´ll just have settled for driving her then..

Bill Verburg · Bill Verburg's Garage

This is worth reading

personally I wouldn't use anything but the Mahle filters

livi · 07-21-2006, 04:45 AM

Thanks Bill. Thats a piece of work!

My current filter is Mahle OC54 'micro-star'. Made in Austria ?!? I suppose it will do for 3k miles.

Bill Verburg · Bill Verburg's Garage

According to the factory it's good for 15000 mi, but I change once a year at less than 3k mi.

livi · 07-21-2006, 05:12 AM

I guess that answers my question. According to factory good for 15k miles, we change at approx. 3k miles along with oil. An intermediate change at 1.5k miles does look a bit over cautious.

randywebb · 07-21-2006, 11:49 AM

Note the question as posted is not about oil change intervals but about shorter oil FILTER change intervals...

The answer to that is NO - assuming that blockage has not happened. Filter media filter more efficiently when filtrate is captured by the media! This is the prinicple of ion exchange columns for example.

But for oil they say to change at least every 12 months no matter the mileage (see BV reply above) & its what I do.

If in doubt ----> MEASURE (to paraphrase Wm. Thompson, Lord Kelvin (aka "Billy"))

So start up a testing regime... search on oil analysis.

cnavarro · 07-21-2006, 11:58 AM

You want the highest level of filtration with the least amount of restriction. A good example of high filtration are the pure one filters - they are cram packed full of thick pleats that filter as well or even better than synthetic element filters, but clog up very quickly and restrict flow badly. I've seen them on a 914 starve an engine for oil and/or blow the filter up because of the high pressure in the filter from getting clogged with less than 3000mi on the filter. The Mahle filter is a good filter, don't get me wrong, but it doesn't have the filtration of a filter with a synthetic element.

ianc · 07-21-2006, 12:49 PM

What do you mean no new projects Markus? Did you ever do those front shocks? How about the SW chip?

Cruise control working?

ianc

livi · 07-21-2006, 01:21 PM

Randy, I believe I´ll just give it a rest. Changing filter more frequently than a 3k oil change is probably ridiculous. Particularly with an 21 year old engine. I won´t save it by weekly filter changes.

Ian, shocks were long time ago. So are turbo tie rods. Recently did the shift linkage bushings - and manage to get the coupling even better adjusted than the PO. Then I did the service including the valves successfully.

I am having a sublime combination going with an "everything you need to know - board" together with a **** load of beginners luck. Hell, I am on the roll here - on my way to learn the basics about vintage air cooled. And I can´t wait to come up with my next project. Have not done the rear bushings for example. Thinking of a new drop link etc, etc.

Still a bit cautious about the SW chip. Despite all superb references - and I do believe they are correct, a certain Loren´s conviction of the contrary keeps popping up in my head. Besides, I am very pleased with the performance already.

Ah, the hell with it, I better send SW an order tomorrow...

ianc · 07-21-2006, 01:23 PM

Quote:

I better send SW an order tomorrow

It's worth it, believe me...

ianc

cbeers · 07-21-2006, 02:57 PM

+1 for the SW chip. that with a cat bypass and nice exhaust can wake up the 3.2 nicely. Not wheelie material, but nice gains.

You rebuilt your suspension yet Markus?
Poly bronze bushings yet?
headlight relays?

Just tryin' to help you out

Hey Ian, what are you going to do with your SC?

-Chris

ianc · 07-21-2006, 03:29 PM

Quote:

Hey Ian, what are you going to do with your SC?

Ummm... Sell it?

I just need to find the time to polish the old girl up, but it's been a little hard lately to find the time. I just completed a top end on the Carrera on Tues, so I'm still in recuperation mode.

ianc

livi · 07-21-2006, 03:39 PM

Thanks for the tips, Chris. Yes, I think a SW would go nice with my Euro premuffler. No cats around here (well theres one on the porch). And yes I believe bushings will be next too.

cbeers · 07-21-2006, 05:50 PM

Add a Borla exhaust and that's what I have.

For bushings, I think the Elephant stuff is top notch. You already know this I am sure

-Chris

donstevens · donstevens's Garage

Quote:

Originally posted by livi
Randy, I believe I´ll just give it a rest. Changing filter more frequently than a 3k oil change is probably ridiculous. Particularly with an 21 year old engine. I won´t save it by weekly filter changes.

This is correct. At 3000 mile inetrvals it makes no sense to change filters at 1/2 way.

However, if any readers out there are attempting to extend synthtic oil drain intervals beyond 7500 miles, it is prudent to change the filter at 7500 miles. This assumes of course that the extended drain interval program includes oil analysis to support the results.

Changing the filter in between oil changes no only provides clean filter media for the second half of the drain interval but also through the use of make up oil partially restores some of the additives that were used up in the first half of the drain interval.

Don

cnavarro · 07-22-2006, 04:56 AM

Well said. That is basically the same recommendation that Royal Purple makes with their product - 15k interval with filter change either at 5k or 7.5k, depending on filter size and oil capacity. Considering how large the filter is and how much oil the 911 holds, 7500 mi is just fine.