Determining a filter change interval

[dparm]

Okay, so the OCI stuff is easy to figure out -- TBN, viscosity changes, fuel contamination, etc. Hypothetically let's just say I have determined that a 10k OCI is optimal.

How do I know if the filter is able to go that long?

FWIW, the car is a 2005 Audi S4 that uses a Mann filter element dropped into the housing, like this:

 

[Quattro Pete]

The only thing I can say is that these exact same Mann cartridge inserts are used on my car and many newer bmws, and they are expected to last through the whole term of the variable OCI which can be as high as 15K miles or even more in some cases. 10K miles should not be a problem at all, unless you're running some sort of engine cleaner additive (such as AutoRx) in an effort to remove huge amounts of sludge.

I'm doing a 10K OCI right now... but it'll be a few more months before I complete it and get a UOA done.

 

[Quattro Pete]

By the way, do you take 290 to work at all? I see this nice charcoal gray S4 on there once in a while... makes me want to buy one.

 

[dparm]

I live and work downtown -- car is not a DD (I take buses).

 

[dparm]

It's a good sized cartridge so I'm sure it can hold a lot. I was just wondering if it's worth it to change the filter at the 5k mark (halfway through the OCI).

 

[Quattro Pete]

I wouldn't.

 

[Sayjac]

How long would it take you to cover that hypothetical 10k?

What is the spec(s) that your owners manual lists for filter change?

Without knowing the answer to the second question, I'd say if you did the 10k in a year or less, the Mann cartridge filter would last a 10k OCI. I agree that I wouldn't just change the filter only, out at 5k.

I would use the owners manual as a guide though.

 

[dparm]

10k is oil + filter change service interval.

10k for me is about 18 months. I don't drive much.

 

[FZ1]

I wouldn't go beyond 12 months on the oci. Change it every Fall. No interim filter change.

 

[Quattro Pete]

Originally Posted By: FZ1
I wouldn't go beyond 12 months on the oci.

Based on what? We've seen a number of UOAs here where the oil went much past 12 months in service and didn't suffer from it. Now, if he's only doing very short trips where the engine doesn't get up to operating temp long enough to burn off moisture/fuel, then I'd agree to change it sooner rather than later.

But if he already decided on a 10K oil change, then the filter part of it is not an issue, IMO.

 

[FZ1]

Based on my preference to have fresh oil installed in the Fall so it will be fresh over the winter.

 

[Quattro Pete]

Originally Posted By: FZ1
Based on my preference to have fresh oil installed in the Fall so it will be fresh over the winter.

I presume you want it fresh for winter because you figure it gets beat up on more during winter? But if so, why continue to run with a beat up oil over the following 3 seasons? Why not change it right after winter?

Just playing devil's advocate here.

 

[dparm]

I change every 5k anyways. Car gets a lot of track time and Blackstone advised me to keep the OCI short. Plus I am skeptical about pushing this 300V past 5,000.

 

[HTSS_TR]

The Mercedes uses similar cartridge filter and OCI can be up to 18k miles, for drivers that drive mostly on highway and accumulate that much miles in a year or less. Quattro Pete is corrected that you can do 10k OCI without changing filter at 5k. Provided that most trips are more than 10 miles.

My E430 OCI is 12-13k/1 year, I'm debating about re-use the oil filter for 2 OCI's. Every time I changed the oil the filter seems to be in very good shape, no debris of any kind on the filter. The one reason I'm thinking of using a filter for 2 oil changes is it's more efficient in filtering as it accumulate some miles.

 

[FZ1]

That's what I,do. I change in March and September. The op was talking about 18 months which is too far,for me,anyway.

 

[AuthorEditor]

I usually change the filter in early November, on a weekend day that happens to be when a solid frost is on the ground and I have to lie on my back under the car and freeze to death. Then in the spring I usually choose a day when it is pouring cold rain so I'm laying in puddles under the car. Works for me!

 

[dparm]

Ha, fortunately mine is right on top of the engine. It's directly beneath the plastic trim piece that has the Audi rings:

 

[Jim Allen]

Not the least bit afraid to run long intervals.

FOr your consideration, not that I'm likely to change your mind, go onto the bypass filters area and look at the UOA/PC test I posted there. Look at the oxidation and nitration number and TBN on the R-10 15W40. That was 100 hours (the equiv. of 5-6K miles) and two years on a tractor that sits in an unheated barn for months at a time without running, then is used for a couple of weeks hard, then parked again. If the oil holds up in that situation, the even better oil you guys use should hold up in much better conditions.

Just debating the interval issue here... not trying to interfere with the quality time you obviously enjoy with your cars. BTW, my car and pickup are also on "mileage only" OCIs, which turn out to be about 18 months+ for the Honda and about the same for the '05 F-150. UOAs are great. The truck is getting a bypass setup (an experiment more than anything) and I plan to run 10-15K and 2-3 years if possible.

 

[Sayjac]

Quote:
BTW, my car and pickup are also on "mileage only" OCIs, which turn out to be about 18 months+ for the Honda...UOAs are great.
I'm assuming your Honda is not under warranty? I know it's oft debated, but I wonder about the cost/benefit of doing regular UOA's and extending past manufacturer OCI, versus just doing a shorter OCI, in this case the Honda recommended 1 year max (not very short) or OLM 5-10%. Not being critical, just a thought.

As for the OP, that is one clean looking engine. Very nice.

 

[FZ1]

Yes,it is a beautiful engine. That'll be $50,000,please