General question about engine oil

[PorscheFan]

Hi,

I was wondering if 5w-30, instead of 0w-40 oil is used in 996, what effect or feeling it will be when driving? Accelerating slower? or bad to engine? Or nothing at all? <_<

Thanks in advance.

[geza]

Porsche states 0W40 Mobil 1 is factory fill...............there is an approved list of oils on this website in the TSB section - some of which have different viscosity ratings.

There is no approved oil that is a 30 blend - so stay away from it. Some 911 drivers who live in warm/hot climates - or who track their cars as such, use Mobil 1 15W50.

You won't feel any difference with 30 weight oils, you may hear some additional valve/lifter noises because of its lower viscosity when hot - but you may feel a lot of difference in how much money you have left if the engine fails due to incorrect oil.

Edited October 21, 2005 by geza

[umn]

Hi,

I was wondering if 5w-30, instead of 0w-40 oil is used in 996, what effect or feeling it will be when driving?  Accelerating slower?  or bad to engine?  Or nothing at all?  <_<

Thanks in advance.

<{POST_SNAPBACK}>

5w-30 is totally unsuitable. The lower viscosity and also lower viscosity index make the oil simply too thin at higher temperatures.

The biggest problem, however, is the reduced HTHS (high temperature high shear) viscosity, which in 5W-30 Oils is usually only about 2.7 mPa.s, whereas Porsche recommend 3.5 mPa.s according to ACEA A3 specification. This could easily result in main bearings failure under high engine loads or otherwise simply excessive wear.

Cheers

Uwe

[geza]

Uwe,

If your comment about 3.5 mPa.s specification by Porsche is correct, then it sheds a whole new light on Mobil 1 0W40.........with regard to being Porsche approved. The Mobil 1 website lists the 0W40 specification for ACEA/API shear at 3.6mPa.s. Follow this link and you can check:

www.mobil.com/USA-English/Lubes/PDS/GLXXENPVLMOMobil_1_0W-40.asp

I don't know how much of a factor shear resistance is for an engine/lubricating oil combination as deemed by the factory, but by any measure, 0W40 barely passes the standard set by Porsche. There may be other redeeming factors that 0W40 possesses, but the biggest one seems to be cold temperature performance/flow - and the ability for it to be regarded as a global oil for all climates.

I'll stick with garaging our 40th during the winter months, and running Mobil 1 15W50 with its 4.43mPa.s specification.

BTW - pour point for M1 15W50 is spec'd at minus 42 C, and for M1 0W40 it is minus 54 C.

Methinks this 0W40 issue is more marketing than good sense for the engines/cars we share the passion for.

[ar38070]

There is all kinds of information floating around about Mobil 1 oils. Unfortunately it is hard to get consistent info about the different grades and versions. For example:

Regardless of weight, the new formulations are different than the older ones. Supposedly the new 15w-50 is not the same as the older red cap version. If you find red cap 15w-50 I believe it is old stock. The new versions are not color coded like before.

0w-40 supposedly has less additives than before and this may be true of all of the new formulas. Supposedly this was done as it is better for the catalytic converters.

15w-50 is no longer on the approved Porsche list. Who knows why.

[geza]

The new Mobil 1 15W50 (non red cap version) belongs to the recently released "Mobil 1 Extended Performance" line:

"Mobil 1 Extended Performance 15W-50 is also well suited for weekend racers who are interested in outstanding engine protection for racing engines and are looking for a higher viscosity oil." - this taken from the Mobil 1 website.

The difference between Mobil 1 Extended Performance and regular Mobil 1 is:

"Mobil 1 Extended Performance formulas are designed specifically for today's longer service intervals and are guaranteed to protect for up to 15,000 miles or one year."

"Mobil 1 Extended Performance has a unique formulation with boosted level of protection and performance. These formulations with the Advanced SuperSyn System contain 50 percent more SuperSyn, 36 percent more anti-wear additives, and 37 percent more cleaning agents than the current Mobil 1."

Since Porsche oil changes are officially rated as a yearly maintenance item - Extended Performance would seem the way to go........wonder if a 0W40 version will come out?

A global non seasonal oil recommendation seems to be the only driver for this, and it could be at the expense of having best engine protection vs. globally "acceptable" engine protection.

Without seeing torn down engines at Porsche after defined testing, we'll just never know.

[umn]

...

If your comment about 3.5 mPa.s specification by Porsche is correct, then it sheds a whole new light on Mobil 1 0W40.........with regard to being Porsche approved. The Mobil 1 website lists the 0W40 specification for ACEA/API shear at 3.6mPa.s. Follow this link and you can check:

www.mobil.com/USA-English/Lubes/PDS/GLXXENPVLMOMobil_1_0W-40.asp

...

Porsche requires compliance with ACEA A3, which in turn stipulates HTHS viscosity of 3.5 mPa.s or higher. Mobil 1 0W-40 is OK, because once an Oil is above 3.5 mPa.s it is fine, it's not the more the better. A bit similar to being allowed to drink alcohol in public: Once you are 21, you are fine. It's not that once you are 25 or 30, you are allowed to drink even more... :cheers:

Cheers

Uwe

Edited October 24, 2005 by umn

[aracerx]

Everyone is right! even Uwe (very good stuff).

Bottom line-Unless your running the Daytona 24hr., and are "flat out" for extended periods; the viscosity parameters of the predisposed oils would do fine. Most importantly, I believe, are the ridiculously long oil change intervals! BTW-no one mentions the necessity of proper warm-up on bearing longivity.

[aracerx]

Everyone is right! even Uwe (very good stuff).

Bottom line-Unless your running the Daytona 24hr., and are "flat out" for extended periods; the viscosity parameters of the predisposed oils would do fine. Most importantly, I believe, are the ridiculously long oil change intervals! BTW-no one mentions the necessity of proper warm-up on bearing longivity.

[Hroussard]

Everyone is right! even Uwe (very good stuff).

Bottom line-Unless your running the Daytona 24hr., and are "flat out" for extended periods; the viscosity parameters of the predisposed oils would do fine.  Most importantly, I believe, are the ridiculously long oil change intervals!  BTW-no one mentions the necessity of proper warm-up on bearing longivity.

<{POST_SNAPBACK}>

Now here is an interesting topic. WARMING UP THE ENGINE. What do you guys do?? I start the engine, wait for about 5-10 seconds, put the car in gear and start moving. I do not rev the engine above 3K revs until the temp gauge is at least on the number 8 of the dial. I have been told that idling the engine when cold for a while is BAD. When all systems are go and all the dashboards lights are out it's time to GO !!

HarryR

[ar38070]

Here is a table showing oil analysis for some of the current mobil 1 products for reference:

[umn]

...

Now here is an interesting topic. WARMING UP THE ENGINE. What do you guys do?? I start the engine, wait for about 5-10 seconds, put the car in gear and start moving. I do not rev the engine above 3K revs until the temp gauge is at least on the number 8 of the dial. I have been told that idling the engine when cold for a while is BAD. When all systems are go and all the dashboards lights are out it's time to GO !!

...

Yep, that all sounds sensible.

The reason that idling a cold engine is bad is that during cold idle the DME makes the mixture very rich in order to compensate for fuel condensating on the cold intake and cylinder surfaces. The condensing petrol makes the oil thinner which in turn increases wear.

One thing to keep in mind though is that if the temperature gauge is in the middle it means the coolant is warm but not the engine or the oil. Oil temperature significantly lags water temperature. This is true even in a 996, where there is a combined oil-water heat exchanger so the water should warm up the oil during the initial warm-up. Still, once you've got about 80 Celsius water temp, your oil is only at about 50-60 Celsius, so I'd wait a little longer. The whole thing is not that critical as modern synthetic 0W-40 oils give you almost full protection from about 60 Celsius, not 85 like the old mineral oils.

Cheers

Uwe

[wrljet]

Is it permissible to mix different grades of Mobil 1?

Say the crankcase is filled with 0W-40, you're two quarts low, and all

you have handy is 5W-40?

Bill

[1999Porsche911]

Is it permissible to mix different grades of Mobil 1?

Say the crankcase is filled with 0W-40, you're two quarts low, and all

you have handy is 5W-40?

Bill

Yes it is fine to mix different grades of oil.

[gcp]

Have any of you heard of Coastal Full Synthetic oil? At $3.5 each I picked up six quarts of 10W30 to try in my 1990 740 Volvo. Now that's one workhorse of a car!! My winter vehicle while my garage queen stays nice and dry/warm in the garage :D

Can't find much data on the net on this oil but I'll keep looking.

Thanks,

Edited December 7, 2005 by gcp

[CGB]

The reason that idling a cold engine is bad is that during cold idle the DME makes the mixture very rich in order to compensate for fuel condensating on the cold intake and cylinder surfaces. The condensing petrol makes the oil thinner which in turn increases wear.

Cheers

Uwe

I'm curious here - I don't understand how condensing petrol in the intake or cylinder wall makes the oil thinner..

[Kim]

I'm curious here - I don't understand how condensing petrol in the intake or cylinder wall makes the oil thinner..

Since my shade tree days hopping up Chevy 283s, it has been my understanding that raw, unburned fuel from an over rich mixture will drain down past piston rings and mix with / dilute oil in the crank case.

I'll leave it to the real mechanics here to confirm or deny that common belief.

Kim

2000 Cab

[wrljet]

Also, in some engines with various aspects lubricated by splash and

runoff from other components, the cold thick oil and low idle RPM

causes those parts to run w/o proper lube.

Bill

[PeterC4]

I think you need to guage the temperature your car will operate in. I live in Toronto, Canada and during the winter months I use 5W-30 in accordance with the details in my manual. I have a 2000 C4. The car runs fine with no difference in noise levels.