What oil would you recommend (ctxt!)

[FrayAdjacent]

I'm going to be changing the oil in my recently aquired 2001 Boxster. I have no idea when the oil was last changed, and since I'm doing and have done a lot of periodic maintenance, I might as well do the oil!

I will be using Mobile One Synthetic, for sure, but I'm not sure which weight will be best.

GIVEN:

- My daily commute is short, the engine will be up to operating temperature within a mile of destination
- I drive few enough miles that I likely won't be changing it again for 12 months
- It gets HOT here in Texas in the summer
- It doesn't usually get below freezing for long in the winter

In you guys' opinions, would it be better to use a 10W40, or 15W50? I think the 40 weight, so that it will flow better in my short trips, where the engine is barely up to operating temperature by the time I get to work (or get home)... but I'm thinking the 50 weight, because it gets HOT here in the summer.

Would 50 weight be OK given that we rarely ever get below freezing here? We DO have weather below 50 degrees quite a bit, but lower than 40 is much more rare.

I appreciate your experienced input.

Mobil 1 0W40 or 5W40 are the recommendations by Porsche.

[Travis]

Porsche recommends Mobil 1 0-40 and that is what I use in mine.

Fray, you might want to look into Redline's oil products too. Some Forum members here speak very highly of these oil products.

I am currently running Redline 5W40. I don't have enough experience with the product yet to make any statements.

[porschedude]

I use 10W30 Mobil 1 in Texas. I think 10W40 or 0W40 will be fine too. Yes, Porsche recommends Mobil 1 but I think other brands are fine too.

[FrayAdjacent]

Well, I'd check into Amsoil, but for this change, I'm going to have to go with something locally available. Walmart has a ton of Mobil One.

Maybe later in the year for the next oil change, I'll look into something like Amsoil.

(used Amsoil once in my previous car... it was great oil! The first tank of gas after the oil change rated about 4mpg more than the previous tank, under similar conditions. It went back down to average over a few tanks, tho)

[UroTrash]

Fray, don't be fooled by what it says in your owner's manual.

As noted above Porsche has changed their minds about viscosities in cars old and new (well, at least liquid cooled cars) and now recommends the Zero-W40 for all of them despite the data in the owner's manual..

[CJ_Boxster]

I have a question, and its pretty stupid... Is 40 Weight the same as 0-w40?

[UroTrash]

Originally Posted by CJ_Boxster

I have a question, and its pretty stupid... Is 40 Weight the same as 0-w40?

No Far from it.

Straight 40 weight is really really thick when its cold. 0-w40 flows like "zero" (actually not exactly zero, but close) when cold, and acts like 40 when hot. A true miracle of nature that.

[CJ_Boxster]

I just got off the phone with Royal Purple, while i know they dont have 0-W40, I asked if there was a way I can leave a message or suggestion of making a 0-W40 for Porsche Boxsters and they said that they are already developing that weight cause there are alot of desiels and clean cars that use 0 weights for emissions, So soon we shall have 0-w40 from Royal Purple.

Right now Im using Royal Purple 5-W50 which is bad.... but the car does run much better than it with the correct weight of mobile oil. I've used the correct weights in my other cars i've had and that oil is nothing short of amazing... i mean it litterally polished my cams and bearings on my 1967 mustangs and 300zx TwinTurbos.

I just cant wait for the correct weight from RP!!!! I'll soon change my gear oil and will use the Royal Purple brand, especially since i have 103,000 miles on the syncros.

[MNBoxster]

Originally Posted by CJ_Boxster

I have a question, and its pretty stupid... Is 40 Weight the same as 0-w40?

Hi,

No, it's not the same. Multi-weight, or Multi-viscosity Oils contain long-chain molecules called polymers. At cold temperatures, the polymers are coiled up which allow the oil to flow as an Oil with the 1st number (W) weight.

But, when the oil warms up, the polymers unwind into long chains that prevent the oil from thinning as much as it would otherwise. The result is that at 100° C, the oil will thin as much as the higher viscosity number indicates. Another way of looking at multi-viscosity oil is to think of a 0W-40 as a 0 weight oil that will not thin more than a 40 weight would when hot. Hope this Helps...

Happy Motoring!... Jim'99