Ive heard , tons of people say they love 0w-40 oil.....thin oil worries me on 2 counts,..1 being the 0 part creeping past old seals ,,,and 2 being when older porsches were built engine parts had tolerances that required heavier oils to allow for seperation of metal to metal parts....please feel free to share your opinions on thin oil

 

JMHO,.......

Leave the 0w-40, 5w-40, and 5w-30 oils to the water-cooled cars. I've seen too many (expensive) issues to ever use those in air-cooled cars.

Stick to the 15w-40, 15w-50, & 20w-50 products unless you must drive in near arctic conditions.

 

Thank You Steve, my last quick question is Mobile 1 makes a great 15w-50 with a little higher zinc levels, i think 1300 ppm......Can higher zinc levels hurt catalitic converters ?..........also porsche has an updated list every so often, as to what oils " MADE " the approved list.....do you think its absolutly imperitive to pick from their " LIST " ?

 

 

Show me a post with failed cats due to high zinc and phosphorus. Cats are cheap. Motors are not.

 

High levels of ZDDP can poison catalytic converters, however I've never had to replace one for that reason, to date. I can tell you that engine parts are far more expensive to replace (parts & labor) than cats are.

I do NOT trust Porsche's oil recommendations for air-cooled cars ever since they used to approve Mobil 1 0w-40 until they offered their own (expensive!) oils for those cars after many years. Money has corrupted their integrity in their push for higher profits.

 

my air-cooled '87 Coupe now For Sale, under my watch received Brad Penn, I've read up on it and believe in the Zinc, agree with above ZDDP comments and was let down when Porsche came out with their Classic Oil but initially didn't publish their Zinc, Phosphorus levels... I also pulled a bit of a "cop out" on the Cat issues, I deleted mine...

 

The cat poisoning is real but it's also something that occurs extremely slowly, the cause is when the Zn & more so P get into the exhaust, this happens more as the engine wears. The secondary issue is the manufacturer's 10 yr emissions warranty. Over that time frame and for the large #s of vehicles involved cat poisoning is a potentially large liability.

 

We have never used anything except 20w 50 oil on our 2.7, carbureted '73 911. Just checked the hour meter we have connected and this engine has 340 hours of mostly track time on it. We do change the oil every 6 months, regardless of track time or right before any track event. Also, we always use ethanol free gas on these older 6's. No cats to worry about .

 

20w-50 covers you down to about 15 degrees F
You driving in colder weather than that?
Lost of people run 15w-50 Mobil 1 Synth w/ ZDDP

 

So where are all the poisoned cat threads on Rennlist? Please provide links.

 

Lack of threads is not an indication of lack of damage, The process is simple chemistry.

It's a slow process that accelerates as the engine wears and burns more oil. Plus even the oils w/ adequate ZDDP have reduced levels. The cooperation of the oil companies, government entities and the manufacturers to limit potential liability in the US is not surprising either. I am unfamiliar w/ what's happening outside the US, but anecdotally it seems that there was less concern there for the liability and long term issues.

It's amazing to me the disbelief in simple science in the modern world, No the car won't blow up from too much ZDDP in the oil but yes, there is continuous and increasing damage done from chemical reactions, mostly from the P, in ZDDP in the cats

 

crap getting into the cat will cause them to be less effective and fail... running rich. leaded gas, etc.
Cats are cheap
Cam shafts, rockers, valves, and labor are NOT
Run high ZDDP.
My AC cars get a 15w-50 or a 20w-50

 

They are in databases owned by the car manfs. who are required to warranty engines in new cars for a long time and comply with EPA emissions regs., also for a long time. Slow damage to the cat costs them warranty $$ so they got the oil co.s to reduce Zn & P from the oils.

 

could not agree more ....

the recommended oil is obviously the factory fill ... shell .... oh no wait hang on ... its Castrol .... oh no wait hang on its Mobil One .... damn , I keep forgetting .. who got the latest contract and wrote them a cheque ?

but speaking of such things I'm pretty Sure Porsche doesn't own a refinery , so who is putting the stuff in the can they are putting their name on ?