Should we trust the extended oil chg mileage intervals ? Toyota and porsche 10 K miles seems crazy to me..

The 996.1 and .2 service interval was 15,000/1yr for the oil and 30,000/2yr for the filter.

So either the car didn't get driven much (probable) and had a service annually (good) or it got driven A LOT (good) and was serviced every 15,000 miles with 9 quarts of A40 oil (good).

Since any 996 is at best 15 years old, and the one you are looking at has 140k miles, I wouldn't worry about it.

How often the oil was changed on the Porsche should be the least of your worries.
 
I had a 2002 Ford Ranger for 19 years, then had to buy a newer vehicle.
I ended up buying a 2021 Ford Escape.
Learning about all the PM is keeping me busy.
I'm mostly concerned about changing any fluids and doing them sooner than recommended.
Especially the life time fluids.

Quantico - Maybe you should go to the maximum of your comfort level (UOA would help).
But then also consider changing the Transmission, Differential and Transfer Case Fluids.
 
........ Do you believe that the ten thousand mile changes protects engines well ?? I can do a mobil 1 oil change even with the porsche large oil volume for 60 or 70 bucks. .... I would be interested in your opinions.. when ford and honda and toyota a long time ago went to 5w20 or 0w30 oils I thought it was crazy too thin an oil. But now I just use it and hope the design engineers got it right.

Manufacturers went to extended oil change intervals to appeal to their customer base. Most new car buyers do not hang out at BITOG, and they don't like to be bothered with automotive maintenance. Especially women buyers. Of which the marketplace is seeing more and more of. The less of it they have to do, the better. They LOVE extended oil change intervals, and will praise anyone who suggests them. It's a bit like a dietitian telling an obese person, they should visit Baskin Robbins 3 times a week. It's what they want to hear..... Not what's good for them.

The movement to water thin oils has been the result of demands put on those same manufacturers, directly due to CAFE mileage requirements. NOT because they protect engines better. Engineers are trying to get these engines to rotate as freely as possible, in order to achieve the highest MPG possible. They are all looking for mere fractions of a mile per gallon. It costs these car companies a fortune if they don't achieve these CAFE requirements. And it adds tremendously to their bottom line, if they do. It's all about $$$$.

Part of this amounts to these companies going to very loose fitting piston rings. This is causing another whole new set of problems. Engines are not only burning oil, but many are having massive fuel dilution problems, (Honda). While others, (Toyota), are having problems with deposits building up inside piston ring grooves, causing seized rings and grooved cylinder walls. With the fix in many cases requiring a complete engine replacement.

The only way to lessen this fuel dilution and deposit buildup is with more frequent oil changes, and going up in viscosity. Which both companies are reluctant to advise their customers to do. Again because of CAFE. So the whole thing becomes a great big Catch 22. I avoid all of it by changing oil often, and use a higher viscosity when I do. And using a new oil filter each time. The only negative I have to deal with, is from these same maintenance haters telling me it's not necessary. And that is easy to live with.... Especially when they are being proven wrong, every time we see all of these issues popping up we never seemed to have before.
 
Have to fix a 55 gallon drum on the back, fit it to the pickup tube, and dump it all overboard after one pass through the engine.

Cheap insurance!
Haha wasn’t that an old James Bond thing, where he was getting chased and he drop a bunch oil on the ground so the guy chasing him would lose traction and run off the road off the road haha!!:D
 
What oil was used for the 10K OCIs? If conventional or semi-syn, your fears may be justified. But if those 10K mile OCIs were done on a synthetic, I think you should feel satisfied the engine(s) are in as good a shape as possible for higher end cars with discerning owners.


If that oil is Porsche a40 or c30 approved.... And how super tough testing to meet that approval. . Then it should be up to it.

Though like Wilson said... Get a UOA to verify that the oil is good too.
 
10k is no problem with synthetic in your Toyota :)

Porsche requires special oil for that 10k. Most Euro cars have specific requirements like mfr-spec oil and/or ACEA-rated oil, and plain old SP doesn't cut it.
 
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