Oil change intervals are one of the most argued aspects of Porsche maintenance. Questions such as how often, what weight, what filter(s), what type, and what other systems that should be checked during an oil service come up.

There are many correct answers. I will try to give you my opinion and that is what it is. An opinion based on over 30 years of centering my skills on Porsche. It seems strange saying 30 years but I love these rear engined machines.

How often? Once a year at least. A 356 with a bypass oil filter that cleans at most 2% of the oil while bypassing the rest should be changed at 1000 mile intervals and the filter changed every other time. This includes 912's. Early 911's with performance carbs. or mechanical fuel injection need 1000 mile intervals. Other early 911's (pre 74) excluding 73 1/2 CIS and standard carbs. can go 3000 miles or once a year. Filter every time with 911's please. 74 to 83 911's can go once a year or 3000 to 6000 miles depending upon on driving conditions. If you flog it, change it! Or if you idle it through traffic, change it. If you cruise and are not a road animal 6000 miles is cool in the year interval. 84 to 94's can go 6000 cruising. Their fuel control is so much better so fuel contamination is not so much an issue. Now we hit the hot button, the synthetic crowd. 7500 max is it. Even though the fatherland says 15K we believe that is too far. After `15K on the oil it runs out like water and has a gritty feel with a fuel smell to it.

What filter? OE only. in all but 356's or 912's. Since they have bypass filters only any filter that fits in the canister will work. After market brands like Fram, Wicks etc. may fit on 911's but they are valved wrong and may bypass oil and not filter it. We only use OE. This is especially true on Boxsters and 996's.

What type? This is the question of passion. Any major modern brand will do a good job. It must have the correct rating for the car. Our house oil is Shell Rotella. This is a diesel oil that was the original oil for Porsche's for many years. It was introduced to me by my Porsche mentor Leo Rapp. We use Mobil 1 at the correct weight for the year model car for the cars that came with synthetic from the factory. It works.

Other system checks. What we do is a safety check. It takes only ten to twenty minutes but these cars are driven hard and need extra TLC. We always check all lighting systems. Wheel bearings, Brake pad and rotor condition along with brake fluid condition. Tire wear and pressure. Suspension components are checked. Battery condition and age are checked. Belt condition and engine hoses are looked at. Oil leaks are noted if any. Windshield wipers and washers are checked. A short road test to check running gear (transmission shifting, shocks, pulling, steering response) is performed and then a final check of oil level. The last and one of the most important items is to fill out the maintenance logbook and write date and mileage on the oil filter.

I hope this helps you.