1997 850 NA - Switched to Pennzoil 5W-40

[oragex]

I use a quart of oil in my Audi A6 every 1200 miles and that is considered normal use for that car, i.e. within normal healthy engine range. As someone already stated, it might be tough to improve on one quart per 3k miles of stop and start driving no matter what you do.

Later Audi as well as other European makes, had an issue with a new PCV system design causing them to use oil. Audi replaced the breather box with an improved design. But in all cases, despite what some dealers say, 1qt of oil every 1000miles is clearly an engine issue.

[xHeart]

5W40 might cut your oil consumption by one half at best, but as an additional benefit it will clean up your engine over time while reducing wear.

How does it clean engine?

...

Does it seem like I don't know what I'm talking about? Probably. So I will speak from personal experience. About 18 years ago I bought my 850 wagon. It had a very low grade dino oil used in it for it's first two years of life and already the engine was brown inside (as observed through the oil filler), and I immediately switched it to full synthetic, and over the next couple of years it slowly cleaned up inside. So there you have it, a first hand testimonial. Which I'm far better at than explaining the scientific properties of engine oil. :wink:

I have similiar outcome after using Pennzoil 5W30 for past 5+ years -- frequent than normal oil change. Much cleaner at oil filler, cap, and dipstick - from thick coffee brown to maple syrup.

[misha]

In 4 months replacement interval it doesn't have time to get dirty.

Leave it for a year and 10-12k km in the engine and you will see what will come out when you change it.

[xHeart]

In 4 months replacement interval it doesn't have time to get dirty. ;)

Leave it for a year and 10-12k km in the engine and you will see what will come out when you change it.

I am encouraged with the idea. On target with Pennzoil Euro 5W-40.

[misha]

I know that owner's manual recommend 6 months for severe service,BUT quality engine oil can be left in the engine for 12 months or 10-12k km whichever comes first.

That said....if you're doing 8-12k km per year,you can change the oil & filter once a year.

[xHeart]

Everybody is going to have a different take on the oil recommendation, but I thought I'd add my experience in case it is of use in your situation... My '97 855 GLT (187k miles) was losing about 1L every 3-5k miles when I used Mobil 1 10W-30. I switched two years ago to Mobil 1 10W-30 High Mileage and the leakage rate went way down -- I'm generally not adding more than a 100-200 mL before the next 5K oil change.

Our 854 is in similar loss of oil situation Jreed.
Now counting on this upgrade from mineral Pennzoil 5W-30 to synthetic 5W-40 to get closer to the same outcome as yours if not better -- minimize loss and extended oil-change-cycle.

[xHeart]

I know that owner's manual recommend 6 months for severe service,BUT quality engine oil can be left in the engine for 12 months or 10-12k km whichever comes first.

That said....if you're doing 8-12k km per year,you can change the oil & filter once a year.

Is PCV immune or just delays clogging with synthetic oil?

[misha]

It's not synthetic oil which prevents pcv system to clog.
It's regular oil change.
Regular oil change is 12 months or 8-10k km whichever comes first...which depends of oil quality....synth or mineral.
After one year in the engine,oil is slowly loosing it's viscosity and detergent ability.
One year is optimal interval for oil change.

[xHeart]

Thanks again misha.

Pennzoil also sell a 5W30 synthetic with high mileage label for cars above 75000 miles -- similar to Jreed's Mobil 1 switch.

For 5W40 grade, the Pennzoil website says 15,000 km -- close -- I average 8,400-mi/13,518-km a year.
I am in extreme cold during winter weather -- street parking overnight. If I follow the yearly oil-change then the next one will be this time 2017 -- after the great lakes winter. Will the 5W40 oil good enough to take me through the extreme cold for those final 3 months of its life/performance?

[oragex]

Synthetic might delay PCV clogging. It won't prevent it though. I'm on the opinion that's short trips that are the main culprit for PCV clogging. A car that has seen only highway driving might never have the PCV clogged. But I might be wrong, stand corrected.

The thing with replacing a synthetic oil at 15000km (or even 25000km if I remember well for some European cars) is mainly a matter of type of traveling. I would probably have no issue changing a synthetic oil at 15000km if I only do highway miles. But as I'm doing only city miles, I will keep a 7000km oil change interval. The other parameter, is the engine oil capacity. The oil in an engine that will hold 5qts will wear out sooner compared with an engine that keeps 8qts of oil.

For very cold winter mornings, I found the Castrol 0W30 to help the engine arm up the faster.