1. Switched from 0w-40 to 5w-40 turbo diesel (DELVAC) Mobil 1 (both).

2. Cool down for 2 minutes (per several national level tuners...) rather than 1 minute, no matter what.


Was 1 qt per about 650 miles. Is now 0.5 qt per 700 miles. I repeated that twice over the last 3k miles....recording things. It is real.


So I am sticking to 2 min cool downs (a PITA when you are late to something....) and the oil. Also putting 5w-50 in in the spring!


JB

 

Beware of thinking that diminishing oil consumption is a good thing. If you put
in straight 90-wt oil or grease you might get even less consumption... Whatever
causes your oil consumption won't be changed by a longer cool-down. If there
was ever any damage from a lack of cool-down, it won't get undone by more
cool-down now, and the damage *is* the burning/coking up of a tiny amount
of oil in the turbo bearings, but won't affect consumption. It'll just destroy your
turbos.
Oil consumption is more complicated issue, but if we assume your engine is
burning it*, we can suspect that it is getting into your combustion chamber past
the rings or past the valve guides, and the thinner the oil, the more gets by.
However, that doesn't mean you should use thicker oil to prevent it. All the
other parts of your motor may be in fine condition and if they have the close
tolerances of a typical Porsche motor, they still need the recommended
viscosity, and to make them all struggle with a thick oil, just to save you $6
every thousand miles is a mistake. In cold climates, you want the oil to circulate
quickly at startup. Thin oil is best for that.
As long as you stay in the viscosity range Porsche recommends for your
climate, you should be OK, but I'd stay as thin as recommended to keep the
motor in overall good health, and simply wait till you eventually open up the
motor to check the rings and valve guides.
Some brand new motors are loose in a way that causes more oil consumption
than others, but still run as strong and long as the others. And sometimes oil
consumption is a bad thing, especially if it's sudden and/or unusual. A leak-down
test might be good info to have. So, we don't know if there's anything for you to
worry about yet, but don't do damage attacking a symptom.
Joe

* Some oils (especially older non-synthetic oils) are a mixture of varying hydrocarbon
chain lengths, and the shorter move volatile fractions can actually evaporate out,
dropping the volume of oil (and thickening it), with no real consumption involved.

 

Joe,

5w-40 and 5w-50 are "approved" by Porsche for the 996TT. I am not sure I ever was over normal as 1000km for a qt was ok (jut under 600 miles), per the manual and the dealer. Per the dealer, some of the engines "just eat oil" which is what they do....from a host of people. You have said the same thing in your post. 95% of the approved oils seem to be 5w-40 fwiw. So, I am not sure why your post comes across as "don't do that and switch to a heavier oil....it doesn't fix a problem...etc." Not sure where you were/are going. I suspect in a healthy engine on the higher side of normal oil use (within spec), the 5w v 0w may help things a tad. Nothing more was meant.

The M1 bottle for 5w-50 says it is good to -40 or so F.... and I only plan to use it in the summer (over 50F all the time).

I suspect if you cool down longer, less oil gets burned. I always did 2 minutes if I "used" the turbos...and 1 otherwise. I have moved to 2 minutes now no matter what I did even if slow for 5 miles at 2k rpm.

I have NO smoke at all. Never had. And, I have always cooled the car down at least 1 min. Every single time. My car's consumption has not varied using 0w-40 since 14k when I acquired it. Many in Europe have noted that going to 5w-50 slowed down consumption and as it is an approved oil, have not had issues.

The 5w-40 has 1200 for the zinc portion, 0w-40 and 5w-50 have 1000.
Minor point, but the Delvac 5w-40 (same as turbo diesel) is gas engine approved, an approved Porsche weight, and perhaps even superior in terms of addititives than 0w-40. I suspect it is equal to 0w-40 in terms of quality.
-
Right now, I think my engine is happy, healthy, and getting only the best. It is in spec and always has been. It has never seen BMC or K&N filters. Only OEM paper air filter keeps the dirt out, and a new one has gone in every 7500 miles since 14k miles. Oil every 4-5k miles, more if I track, and only the best oil(s). 0w-40 and 5w-40 m1 so far. 5w-50 this coming spring. Mobil 1. New. Fresh. I am not sure how much more careful I can be.



JB

 

I must agree ~100% with Joe...I have followed the viscosity debate for years now. The most comprehensive studies I have seen including lab testing of the oil, inspection of the engine components, etc. suggest the most damage done is at start-up...when you want the oil to be thinest (the first number in multi-viscosity oils). I suggest you read Doug Hillary's well documented reports for more information. I'm just skeptical of the oil "usage" claims....(your testing and measurement system are a little suspect for an analytical statistician...)

 

Good then. *I* would stay as thin as possible, but that's just me. Burning
oil in the turbo doesn't just disappear, it turns to tar/coke and gums up the
bearings and destroys them long before you've burnt enough to notice.
So, it sound like your turbos are fine, thanks to your disciplined cool-down
procedure, and that your motor is 'loose', and may be just fine. Porsche does
approve thicker oils, but they present a temperature chart, approving them
for high ambient temperatures. If I were you, I would stay with the thinner
oil for full-motor protection, and just top it off as needed. I'm just saying
don't fight the symptom.
Good luck,
Joe

 

Will do. 0w-40 for top offs to spring.

In spring, I like the 5w-40 and will likely top off with 5w-50....


In the end, the engine is seeing only superb oils, frequently.

I suspect Porsche would not approve 5w-40's if they felt it flowed too slowly, so I am happy.

Funny thing, I get told by some that many are still using 15w-40 Swepco in these motors for years with break downs showing no wear. .... I am not supportive of this at all....but that behavior is out there too.

Anyway, I am using only using what is ok in the manual and two data points on one engine makes a curve no one should believe for sure (statman.... ).


Point is this: if your engine is using over a qt per 1000 miles but is not "out of spec", it is possible that moving to one of the many 5w-40 oils will lower oil consumption a tiny amount. Maybe. Who knows. It is an approved weight of oil for any season according to Porsche. The Mobil 1 variant is a superb oil too. My local indy has an Elf product that is approved that is supposed to have a lot of zddp too....so there are choices.

 

Yeah no harm intended, but your claim is what "we" refer to as pre-mature generalization...just not enough data, taken properly....

 

.....

 

JCB how come you use the devlac M1 turbo deisel oil? does it have the zinc addative ? that no other oil uses anymore ?

the only other oil that i know that has the zinc addative is the valavoline vR1 non sythetic racing oil. 20 w 50 . and thats what Todd K, recomended i use and i have been using .

 

Full disclosure:

The zddp levels per Mobil 1 for the oils are:

0w-40 = 1000
5w-50 = 1000
5w-40 = 1200 (delvac...same as turbo diesel truck, but it is fine in a gas engine)

I am not sure if this is an additive, precisely zddp or what not. It is the number on the website that is given. Others, please help me here.


The timing was suggested to me by Kevin at UMW. Stephen at IA agreed. 2 minutes is optimal. I think these two guys are pretty smart in terms of these cars. So, I am sticking to that.

Nowhere have I seen 20w-50 suggested as OK by Porsche. I know Todd is guru. But, it is not an approved weight. Not in the manual. Not in the tech bulletins. Many wish we had thicker oil....but Porsche.....says no. I'd love to see Todd's data.

Doug Hillary supports 0w-40 and 5w-40 as superb oils. The 5w-50 may not be as good...I cannot remember the exact data. It is still amazing stuff.

I think PE does amazing stuff. Not sure why Todd feels 20w is ok in these cars. I am sticking to 5w-40 as my base oil and perhaps topping off with 0w-40 if cold and 5w-50 if hot..... I reserve the right to learn more, and to go back to all 0w-40. Given all the data, you cannot seemingly go wrong with 0w-40.

The emissions issues on a "diesel" oil may be relaxed, so Mobil 1 may not have had to pull as much out of their "turbo diesel truck" as in other weights. That is my presumption....so it may be better and more "old style" of the current batch of oils.

Mikelly, are you on 5w-40 delvac?

 

Jcb thanks for the reply , i may try that devlac can i get it at your typical autoparts stores we have here ?

 

Delvac 5w40 is the same as truck and diesel 5w40.
Walmart sells them in jugs..

 

I found it in both Pep Boys and Advance Auto.....

When I was last in each store, there was a 5 qts with filter deal a few months ago for about 25$, I got 10 qts and two filters for the range rover....

It was 50c less per qt than 0w-40 last time I was in....if at Walmart in jugs, go that way for sure!

It has been in the car now for 3000 miles. No issues. Less use as noted above. I plan to change at about 5k.

JB