[S_Cal968]

I just recently had the painful experience of replacing my cams due to lack of teeth. <img src="/forum/images/smilies/968/ohmy.gif" class="smilie" alt="" /> And, after calling 5 shops I was fortunate enough to find a German guy that specializes in the 3.0L. After viewing the carnage he asked what brand of oil I use and how often I change it. I responded that I use Mobile1 Synthetic and change it every 10K miles. He went on to say that the owners manual is not the best recommendation; the oil should be changed every 6-7K miles.



This time I was lucky per se; while changing my valve cover gasket I thought to check the cams and sadly they were toast. From what I could see there was one tooth missing from the intake cam and several off of the exhaust cam. And get this - when I got the exhaust cam back, it only had ONE tooth left and it still ran fine!! I often up-shift at anywhere from 5 to 7K, so I consider myself lucky that nothing else happened.

I also talked to Pete over at RS and he said I was extremely lucky I didn't lunch some valves, [which are a C-Note each!]! Typically the damage is done upon start up and the sound is very noticeable.



The moral here is to change the oil more often - it's cheap insurance...

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[rustech]

Sorry to hear about your failure. <img src="/forum/images/smilies/968/sad.gif" class="smilie" alt="" />



How many miles are on your car, and have you ever serviced the variocam chain and pads? I know Greimann would have strongly disagreed with your mechanics opinion. Synthetic oil loses virtually no lubricating properties over a period of 10k miles (esp over the difference of 7k to 10k). What weight oil were you using?



Opinions on oil are a dime a dozen. Your failure sounds mechanical to me.

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[S_Cal968]

My car is currently just under 78k and I'm running 15w-50 M1 Synthetic. I should add that I did run 20w-50 racing oil previously.

I did get the original pads back and they didn't look too bad, not even the lower one was worn. If anything it was the chain that did in the sprockets.



A quick note on the pads; the lower pad is no longer available [except with the $300 actuator] but the one for the top does work in the bottom position. [p/n: 944.105.509.00]



I've heard from more than one source that the chain stretches which cause the failure and I wonder if this has anything with driving style. I always blip the throttle when down shifting which which actuates the vario-cam timing which may cause more stress[?]. Some may use more brakes and don't swing the rpm as much as I do, [just speculating].



Yep, it would be interesting to get some input from Dave G. he's the oil guru.



p.s. cute pic of the little one - Congrats! <img src="/forum/images/smilies/968/smile.gif" class="smilie" alt="" />

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[sasilverbullet]

This topic always brings out the best in all of us! <img src="/forum/images/smilies/968/smile.gif" class="smilie" alt="" /> <img src="/forum/images/smilies/968/smile.gif" class="smilie" alt="" /> Oil change intervals is a belief akin to religion...that said...



There is a website called "bobistheoilguy.com" where a bunch of oil gurus hang out. I've been lurking on the site for over 4 years.



To condense 4 years of reading, that is way too long to be running the oil. You can run it past 5K but that's only with you taking oil samples for analysis every 1K after that.



I run 15w-50 M1 also and I just change it every 5K. I blew a head gasket at 150K and they had to put new rod bearings in. The mechanic said it was the cleanest engine pan he'd ever seen.



If you have more questions, I'll be happy to respond...

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[flash]

lol - i change my oil every fourth time i drive it

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[S_Cal968]

I'm sure the oil co's like that... Are you a stock holder too... <img src="/forum/images/smilies/968/wink.gif" class="smilie" alt="" />

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[Tom in Austin]

Porsche recommends long change intervals in part based on the amount of oil the cars use. A lot of acid and suspended material can be dispersed across 7 qts of oil (my new 928 actually uses NINE qts).



Contrast that with typical Japanese cars that have only 4.5 qts or so to hold the gunk between changes ...

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[Kim]

To me, there needs to be a bit of compromise between wasting resources / polluting the environment and keeping the car perfect. There is no more Jurassic forest left to make new oil. My 944, bought at 86K, was sold at 340K. I used Mobil 1 15W-50 every 12,000 with absolutely no problems. I now in both 968s use the factory specification and Mobil-1. I can generally drive near enough to 24K in a year to ensure that I change it annually. In all my vehicles I just follow what the manufacturer says.

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[flash]

i stopped using mobil 1 when they changed the formula, and it has now been shown to have issues - you can get more specific details on that one from pete - i now use redline



lol - yes, i am sure the oil companies love me



my car sits a lot - therefore when i fire it up, it's rich until the rings expand - fuel in the oil is bad - so, consequently, unless i start driving it more, i have to change the oil more frequently



lol - so i get to keep the oil companies in business one way or the other - frequent oil changes or more gas burned from driving



hmmm - maybe i should have oil stock

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