turbo510

I've always changed the engine oil in my 12-valve 2.8 every 5K miles, often with Valvoline, Castrol, etc dino, but sometimes with a synthetic. However this time, for some reason, the Mobil-1 5W-30 High-Mileage oil is behaving differently. I'm at 9,000 and the oil still looks too fresh to change, and the consumption is also way-down. With 235,000 I'm kind of surprised, though I know that 10K changes or more are not uncommon on new cars. The only fairly recent change to the engine was replacing the OE 2-orifice injectors with 4-hole units, if that could matter.

Huskerbob

Change it at 10,000 and send a sample off to Blackstone for a test.

4Driver4

I've always run dino oil in the 2.8 with changes at 5k.

The new A6 3.2 demands synthetic, so I did the first oil change after 7500 miles, and I sent it to Blackstone. They gave me a clean report, so I went to 10k for the next change. That came back good too, but I can't get myself to extend past 10k.

Bobby Kinstle

I've always done the 8,000 mile factory suggested oil change intervals on my 2.8 with full synthetic. No issues at all with over 165K on the clock. Oil consumption seems largely due to leaky seals and a clogged suction pump. Right now its very low.

Huskerbob

I agree, 10,000 would be a "brick wall" to me. But at that mileage I'm only changing once a year so that's good. Oil changes by the calendar not the odometer

1999Audi

->>>"Oil consumption seems largely due to leaky seals and a clogged suction pump." - I hate those.

I have to add 1qt of oil at ~8k. I always wait till ~10k to change oil

RallyAudi

Running these older vehicles 10K before changing the oil is very risky. Two points:

* What filter are you using, not many of these can take the abuse? Filters made with fleece materials are the best. A good oil filter is usually $10 - $15.

* Clogged up crank ventilation can shorten the life of oil.

If you change it every 5K you will not have any issues.

turbo510

I use MANN 930/21 filters. I just don't see any reason to change the Mobil-1 that looks and smells perfectly normal, before 10K miles.

Actually, the only problem that I've got with the A4 right now is the sunroof, which jammed in the full-open position (my son borrowed the car, and he has the reverse Midas touch). I had to get the headliner down to reach the frame, and take it out to deal with the stuck glass.

Huskerbob

I use a NAPA Big Kahuna, it's huge, filter with Rotella T6 5w40 full synthetic but I'm not sure I will try for 10k. 7k seems like a fair compromise. For me that means no more than 2 times a year. Probably ought to use a calendar instead of the odometer.

RallyAudi

AutoZone carries Mobil and K&N filters which both are great for synthetic oils.