Mobil 1 and Oil Burning with Boxer Engines

Noticed the following when using M1 (the same 0W 40): 1. My 987.1 2.7 - no burning / consumption whatsoever (knock, knock) 2. My friend's 987.1 3.4 - burning / consumption (~1 qt every 1500 mi or so?) - no bore scoping done but doesn't think he has bore scoring (no symptoms) - I gave him two jugs of Castrol 5W 40 and will see if this helps at all 3. My Subaru Outback (also a boxer engine, but xW 20) - burning / consumption - also burning with Kirkland / Costco and Valvoline - less with Pennzoil, Castrol - eventually changed to 5W 30 and no more low warning I guess each engine reacts differently??

Total WAG here...Methinks it's not so much the oil that's the issue; it's the state of each engine. FWIW, per your friend, I don't like the idea of burning 1qt @ 1500mi -- something sounds wrong here. Reminds me of our former MINI in the final 2-3 years before it blew (cylinder 3). Rings? Reminds me of my old '68 VW bug -- coincidentally it was likely cylinder 3 in that one too... I'm a fan of M1; have been for 25+ years in my cars and motorcycles. YMMV, though...

I think the oil consumption is based on two things - the break-in process, and the actual engine design. The break-in is still critical despite some people thinking it really doesn't matter. I've broken in a few new engines (rare that I've bought something new, but it happens) and I think the most critical time is the first 1,000 miles - where the rings and bores become intimately related. Being just a bit gentle introducing them to each other seems to really help, as does varying the driving style/conditions for the 1,000 miles. There is a school of thought (or non-thought IMHO) that says run the piss out of the engine when it's new and it will never use oil. I find that hard to believe. I don't baby the engine, but I also am very conservative with higher-RPM's until the miles start accumulating, and even then - it's higher RPMs (4K and up) for only very brief periods of time. And actual engine design - I believe Subie boxer engines are known for using oil, and also for blowing up every so often. Why? Dunno - but my friends who've bought Subies typically get a new engine in the car while under warranty due to excessive oil use. Or blowing up. BMW Boxer engines (motorcycles - 2-cylinder boxer) if broken in correctly can easily go 100k miles and never need topping up between oil changes (6,000 miles). I know because I've done it on one I broke in. I've also had ones that did consume what I considered excessive oil (about a quart every 1,200 miles) use - but I didn't break that one in. Same design engines - different oil consumption - has to be attributed to break-in. BTW - suggest to your friend that he use Pensotin 5W-40 - https://www.amazon.com/Pentosin-8042206-Pento-Performance-Synthetic/dp/B009PVC1ES Good stuff. My engine is quieter, smoother, no startup lifter-tick using this oil. IIMHO, it is superior to other highly thought of oil such as Lubromoly. I bet he sees a decrease in oil consumption too. FCPEuro also carries it.. and can make up an oil-change kit with it.

My friend has a great attitude though....as he simply take the situation as "oh, I am just refreshing the pan with newer oil every so often"

Agree with everything Don said. Would also add that oil consumption can happen thru combustion (going past rings) , but also thru the AOS. I would try a slightly thicker oil like 5w-40 rather than 0w-40 to see if that helps. It’s also worth trying an oil with a better NOACK rating. I use Redline 5W-50 in my 987.2 with 3.4 liter. It has a great NOACK rating and I’ve used only half a quart after 7 track days and about 2000 total miles since my Fall oil change.

Don, thanks for the info as usual and make sense - my PO was a lady (not being a sexist and not assuming ladies do not drive aggressively - e.g., Danica Patrick?? ;-) but the car was registered under a female name), and as she aged, it was hard to get in/out of the car, hence selling it. I will suggest Pentosin. One funny thing is that he is actually a transmission fluid R&D guy who lives with oil / fluids (a sub of ExxonMobil) and when I inquired about the difference between brands a long time ago, he basically said "who cares about the brands, just get the right spec and change often. Group IV, Group V? PAO? Ester? I don't care and just change often to get rid of junks"

Thanks and this helps!!

It’s tough to blame the oil, but sometimes there are some differences in oil. For example Mobil one 0w40 will drop a bar or two in my 981 over 5k miles. So far Motul 0w40 has not dropped for two 5k mile intervals. Just one data point, so Hard to read much into it. Also have owned a WRX wagon since 2003. Used mobile one 5w30 for the first 30k with no issues while others were blowing motors. Switched to Motul 0w40 since, just in case.

Personally I believe frequency of oil changes is a factor in product choice. There is no question my discarded filters and Mobil 1 still have plenty of life. But I don’t care, vigilant oil changes is cheap insurance. My car doesn’t burn oil and it runs clean, no spitting on the rear bumper cover. It’s the best running Porsche of the three I’ve owned. I always use the “ euro formula” Mobil one too.