Is Mobil 1 0W-40 the preferred weight for the Cayman S ?

I have the 20" Goodyear Eagle F1 tires (wished it came with MPSS) however is the factory 33/33psi working well ?

Thanks all

 

I have heard the experts say to use something other than Mobil 1, such as Brad Penn. My local German Motors shop uses Mobil 1 and I would enjoy hearing more about why some people suggest an alternative oil.

 

It is the oil and viscosity grade recommended by Porsche. Who else has any real authority to offer an opposing opinion?

If you for some reason believe 0w-40 is not ideal for your area there are a number of approved 5w-40 oils and even one 5w-50 oil.

Keep in mind Porsche guidelines call for 0w-40 to be used if temperatures fall below -25C.

As for tire pressures watch out the most visible or quick to the eye inflation pressures may be for a fully loaded car and as a result can be a bit too much tire pressure for a less than fully loaded car.

My advice is to buy a good tire pressure gage and set the tires to some pressure -- starting with the factory/owners manual pressure suitable for the loading of your car -- and after a while try a bit less air pressure. Do not make big adjustments. Try just a 1psi drop and you can even limit this to just one axle. Be sure you check the tires dead cold and of course you are using a good tire pressure gage so you can be sure the tires are all properly inflated.

Once you find a tire pressure setting you like there you go.

Oh, word of warning. I have found, at least with my Boxster, that just a few psi over the factory setting in the front tires results in a mild vibration that could easily be mistaken for a tire imbalance problem. It is not, or was not in my car's case, it was just having too much air pressure in the front tires.

After my experimentation what I found was the best were the factory recommended tire pressures for a less than fully loaded car.

 

Hi,
Thanks for the feedback. So 0W-40 is for temps falling in the -25C (17 Below zero) range....I'm in Charlotte NC and it never gets anywhere near that cold here in the dead of winter. So 0W-40 is definitely not the correct weight oil for the Cayman S here, unless I'm not understanding something.

Regarding tire pressure, I'll read up more in the owners manual tonight, not sure if 33/33 PSI is for a fully loaded car or not. I own a dead accurate digital gauge that I have cross checked with at least a dozen different various gauges and in fact when this digital gauge read 33 psi so did the TPMS in the Cayman as it displayed 33 on all four tires. The +/- accuracy of my gauge is .05 psi.

 

0w-40 is just fine for where you are. Remember its high temp viscosity index is "40" and that's the same "40" you get with a 5w-40 oil.

If where you are the temps never get real cold -- below freezing is what I define as "real cold" -- you can run 5w-50 oil if you feel so inclined. There is at least one approved 5w-50 oil.

Might mention there is no real guideline concerning 5w-40 vs. 5w-50 oil in the Porsche approved oils list. This suggests where one can use 5w-40 the 5w-50 oil is also suitable and vice versa. The only caution Porsche puts out is the -25C or colder thing, then Porsche says to use 0w-40.

Here where I live winter temps never get below freezing and yet real hot days can have the temperature above 100F. (Even the expected mid to high 90's forecast for later this week are pretty darn warm.) So I run 5w-50 in both of my cars: 2002 Boxster, 2003 Turbo.

Might mention that I had 5w-50 oil in the Turbo last Dec./Jan. when I was back east and even with the outside temperature down in the single digits (one day the "high" was 1F!) the engine was just fine. The cold took out the radiators but the oil was ok and the engine cranked and ran just fine. My one concession to the extreme cold was to be a bit more reserved with the throttle avoiding high RPMs even with the engine fully warmed up. This was also a concession to the fact the car had summer tires on it and some days there was blowing snow on the roadways.

Anyhow, if you elect to use 5w-50 oil the 5w-50 oil can be a bit harder to find at the every day auto parts stores though, so make sure you have a place you can pick some up and be sure to carry a jug with the car in case you need to top up the oil level away from home base.

Plus or minus 0.5psi accuracy means one tire could be 33 the other 34. I bet the gage is a bit more accurate than that. If not it should be.

A general rule of thumb is if you want to measure something down to say 0.5psi the gage should read and be accurate to 0.05psi. (10 to 1 ratio.) I dare say for air pressure that's a bit extreme but I think you want a tire pressure gage that if one tire reads 33psi you know the others are within at least 0.5psi (+/- 0.025psi) of that.

That said though my tire pressure gages are nothing super special. I go by the fact that when I measure the tire pressure at one tire then the other tire the needle (or digital display if I'm using a digital gage) reads as near as I can tell the same. Also, I can confirm that when I take multiple back to back readings at the same tire the needle (or display) always reads the same so the thing is repeatable.

I like a gage that holds the reading so I can bring the dial up close and confirm where the needle is.

In this same context a gage with a big dial and wide spaced hash marks or a big bright digital display is preferred over a dinky gage or digital display.