I'm running 15w50 and...............

I had the dealer switch my oil from 0w40 to the 15w50 at the last service. The car is not used much and used to make the clacking sound at startup from time to time. I've noticed this never happens now with the change of oil. However, I've also noticed the car does not rev like it did before. It still revs good especially once heated up for half an hour or so but before it was gangbusters couldn't get to the next gear fast enough. Anyways, I thought some might like my insight on the oil. I'll probably switch back before too long but you never know, maybe I can find something in the middle. I do think the car is safer with the heavier oil and my infrequent driving.................

Try using what is recommended by the manufacturer....5W40 or 5W50...rather than what is suggested by the self proclaimed oil guy...(you know who I mean).

Many dealers are using 5W50 or15W50, especially in the south. You should not have reving problems due to the change in viscosity. Typically, an overfill of oil will cause sluggishness once warmed up. (any oil weight). The 0W40 is simply too thin an oil in warmer climates and increases your chances of valve wear (amoung other things). If you like to hear you valves at startup, go back to the Mobill Water weight. I would use a minumum of 5W50.

"The 0W40 is simply too thin an oil in warmer climates and increases your chances of valve wear (amoung other things)." How do you know this to be a fact?

1999, all I'm saying is I noticed a change in the revving of the car. The noise went away so I know there is a difference................... Maybe the 5w would be better for me. Porsche put the 15w in but complained about it prior. The car runs fine and is not sluggish especially once warmed up. Also, the car is not overfull. It's a great running car with either oil but I do notice a difference in behaviors.

Listen to your engine.

I can listen to my engine and make assumptions just like you. You state several points about the inadequacies of 0W40 Mobil 1 as fact in multiple posts. Where is the data from which you derived these facts. Look... I'm being a bit of a putz about this but I'm not trying to **** you off. I'd really like to know if your position on this Mobil 1 water thing has anything to do with hard facts.

I agree but also wonder if the 5 w might be better suited. Also, is the lucas addivtive a bad idea? My ford expedition has made that sound for years at startup. The mechanic always said normal, it's still running. I recently put the Lucas gunk in there and it no longer makes that sound. It's thick crap and I don't know I'd like it in my car, but it did make the sound go away.

I'm confused. In your orginal post you stated "but before it was gangbusters couldn't get to the next gear fast enough" which leaves the impression that is does not perform as well now. Weather you are running 0W40 or 15W50, there should be no perfomance differences that you can feel once the engine is warmed up. Your lifter noise is reduced or eliminated because there is less bleed down in the lifters than when you were running the Mobil Water. Now when you start your car, the valve mechanism is fully primed and the valve train is tight. This is good. If you have too much bleed down, the valve train is loose and you will have metal to metal banging until the system becomes fully primed. If you go to the 5W50, you may still experience valve noise on the hotter days due to bleed down. If I were where you lived, I would run the 15W50 you currently have in the engine. I run this weight in summer in Chicago. The reason I mentioned suggishness with an overfilled crankcase.....this is the big contributor to oil related damage to the engine because of increased pressure and airation. Put a quart more oil in the engine than it should have and you will see as much as a 5% decrease in engine performance simply because of the increased drag on the crank. For those that doubt this - next time you dyno your car, throw in an extra quart of oil and watch your numbers drop.

No, once the car is really warmed up, after a few high speed revs, it feels similar. It's mostly just at the beginning as I exit my neighborhood and enter the first real road. This is where I notice it the most. I think it pulls a little power out but not sure how much. I feel like I can feel it but I'm not a Jedi either.

I noticed the same as well... there is some horsepower loss with swtiching to a thicker oil which will affect your acceleration; this is well documented on an engine dyno while comparing different oils.

I've posted many reasons why on this forum if you care to do a search. I have yet to find anyone that will answer the question "WHY is 0W40 better for your car". Seems to me that the only reason is because Porsche says so? Tear down an engine that uses too thin an oil and if there are hydraulic valves, you find alot of slop in the tappet cylinders, scouring of the journals, and of coarse, the ever continuing seal damage. Don't forget the oil blowby when the oil temps gets 240F+. Want to reduce or eliminate the 2800 - 3200 rpm jerkiness caused by the variocam engagement? Want to reduce oil burning (increase HP)? Want to reduce or eliminate valve noise (which means wear) at startup? Want to better protect your engine seals? Want to lower your oil temps? Want your engine to last longer? Get rid of the 0W40 in warmer climates. Even Porsche DOES NOT recommend 0W40. It is simply one of the approved oils. If, in fact, 0W40 was the oil of choice, Porsche would only approve 0W40 for their engine and not even list any other oils...wouldn't they? For what reason do they list a 50W oil as approved? For what reason did some 996's come factory filled with 15W50? Seems to me that Porsche made a mistake...either orginally or now.

"I've posted many reasons why on this forum if you care to do a search. I have yet to find anyone that will answer the question "WHY is 0W40 better for your car". Seems to me that the only reason is because Porsche says so?" I've read many of them. They(Porsche) likely have data. "Tear down an engine that uses too thin an oil and if there are hydraulic valves, you find alot of slop in the tappet cylinders, scouring of the journals, and of coarse, the ever continuing seal damage. Don't forget the oil blowby when the oil temps gets 240F+." Have you torn down a M96 motor that used 0W40 predominately and seen such slop and scouring? What's the temp at which blowby occurs when you switch to the 50W? "Want to reduce or eliminate the 2800 - 3200 rpm jerkiness caused by the variocam engagement? Want to reduce oil burning (increase HP)? Want to reduce or eliminate valve noise (which means wear) at startup?" I have none of these issues now. I'd think you'd have to be burning a lot of oil to actually increase hp by going to a heavier oil. In fact I doubt it is possible - but I'm just making an assumption.

OMG, I used to try to counter some of the mis-information on oil...i surrender....1999porsche911,please don't take this the wrong way because i see that you do have some useful info occasionally, but you are totally misguided on this one....

Well, you have my recommendations from 35 years of exoerience, but run what you want. If you have no problems, then, by all means, stick with what you are using. If you are burning oil. having valve noise, leaky seals, jerky variocam engagement, then, why wouldn't you try a better oil? So, like I always ask...why did Porsche recommend 15W50 for the orginal 996's? Why did they recommend using nothing less that a 15W40 in temperatures above 90F? Did the SAE ratings change? Did their engineers make a drastic mistake filling their engines with 15W50. Did all those car's engine blowup because of it? We know for a fact that Porsche screwed up big time with their oil recommendations. The question is when? Now or then?

You don't understand viscosity and how ratings work...there a number of technical papers on the subject that you would enjoy reading. and 15w50 was never an original fill...it is not, and was not availble in Germany...it may have been a 5w50 M1 at the time...

[QUOTE=1999Porsche911]Well, you have my recommendations from 35 years of exoerience, but run what you want. [QUOTE] May I ask what your 35 years of experience are in?

My engine has always run 0W40 Mobile One and has no issues. I also live in a warm climate (it is 106 today) and my car has never been out of Texas since new. I have no jerkiness in my Variocam as described above nor any of the other problems mentioned above. My car does consume (not burn) some oil, especially on the track. On a single day at the track, I can consume an entire quart of oil. These engines are designed to consume oil as normal per Porsche and is plainly stated in the owner's manual to do so. If you are not, I would be extremely concerned that there is a problem with the cylinders getting lubricated that could lead to a major engine failure. The thin oil is intentionally used by Porsche to complete lubricated the cylinder walls to reduce wear in the flat 6 engine. In fact, it is thicker oil that can damage internal components from not flowing properly due to the flat engine design. It is clearly stated in the owner's manual to not run the engine over 4200 rpms when the engine is cold and until the oil has warmed up for this reason. If my car was leaking oil, the fix isn't to run thicker oil that can't leak through; it is to fix the seal and actual cause of the leak. If you have a hydraulic lifter that is leaking or sticking, again the problem is with the lifter; not the oil. There is a lot of misinformation in this thread. Not only does Porsche recommend Mobile 1 0W-40, but VW, BMW and Mercedes all use (as delivered OEM) and recommend this same oil for their performance models. Why? Here is the spec sheet on Mobile 1 0W-40. Compare the hot and cold viscosities to your other oils: http://www.mobil.com/USA-English/Lub...il_1_0W-40.asp Here is one of the independant tests run on this oil against the best performance oils including Royal Purple Racing 21. Not on did Mobile 1 0W-40 make the most power, it did so with one of the lowest wear levels measured. http://www.performanceoilnews.com/oi...nst_oils.shtml

You're wrong. The early 996 WAS factory filled with 15W50 here in the States. Boy, for being so sure of yourself, you could't be more wrong. Rather than challengining everything I say (which you seem to enjoy doing), why not do a little research or maybe offer you're own suggestions rather than simply say mine are wrong. For example...do you know what the percentage of engines that burn and/or leak oil are running 0W40? Might be a nice poll to conduct. How many dealers in the south actually use 0W40 in the summer. Calls to 17 of them south of the Mason/Dixon line indicated that only 4 of them do..even under warranty. WHY? Which oil will provide better shear protection in hot tempertures and less leakdown, 0W40 or 5-15W/50? That is a proven answer.

So what's the difference in consuming oil or burning oil. That's a new one for me. Burning oil, or "consuming" oil as you put it, is par for the Mobil 0W40 many times,especially at track temps. Unless you are leaking a quart of oil at the track, you are losing it into the combustion chamber, robbing you of power and increasing your knock risk. Try moving up to a 15W50 and see what happens. Of coarse you'll get more power with a thinner oil, but at what cost. The amount of oil being mixed in the combustion chamber with your fuel probably is offsetting any gain you might get.

Steve did a pretty good job . Or as was the case with every other model 911 previous, they changed the oil spec/factory fill about two years into production time once/if they received enough data to warrant a change.

Steve made no arguement for a 0W oil, but a 5W oil. I still am waiting for someone to give a valid reason why you should run a 0W40 oil.

I was reading around on the internet to get some different perspectives on oil viscosity and many of the authors suggest that lower weight oils are now recommended because engine clearance tolerances are much tighter than in the past and as such, a lower weight is recommended, if indeed not preferable to a higher weight which may cause damage to the bearings and seals. I don't want to aggravate anyone here with this information because I'm not much of a shopsmith, but the arguments for both sides do make some logical sense. I guess the argument for a higher weight comes down to how hard one is driving the car at how high a temperature. Anyway, here's the link to the article. Yes, I know it's an Audi site but it sures seems that the rationale still applies. Here's some highlights: "Driving at 75 mph in an Audi requires only about 25 hp, and does not heavily load the engine. Your engine is likely more than well protected with an API SJ 5W-30 if you drive mainly on public roads, and do not average speeds greater than 100 mph over distances greater than a few tens of miles. Short sprints up to 130, if you are fortunate enough to live where that is possible, should not cause a problem. Only sustained high-speeds heat the oil enough to significantly reduce viscosity. Many people have reported that even at local track events their oil temperature has not increased dramatically. Therefore, the only conditions which might require 5W-40 are those which result in prolonged heavy loading of the engine, such as "high-speed, long-distance driving," or towing a heavy trailer up the side of a mountain. Given that, it is almost certain that higher viscosity oils, such as 5W- and 15W-50, are complete wastes of horsepower, placing undue (though minor) additional strain on your engine, and raising operating temperatures for no real benefit." Pretty interesting stuff....

I surrender again.....

You're not French, are you?

Today I spent time trying to track down Mobil 1 5w50 oil here in the US; only Mercedes Benz dealers can order 55 gallon drums of it, and the Canadian distributors will not ship it to the US due to Mobil's restrictions. Any Canadians know of anyone who will ship it to the US? I spoke with the tech guys at Mobil headquarters [phone removed]), and they indicated that the 0w40 oil can be brought close to 5w50 levels by mixing 0w40 with 15w50 at about a 1 to 1 ratio. They also indicated that 5w40 Delvac won't be different than 0w40 for non-winter driving (driving in LA). Do the warring oil factions or gurus here feel that the mixing of 0w40 and 15w50 may be a solution?

You can run Delvac 1 or feel free to mix M1 synthetic to achieve your desired viscosity...i can send you the formula if you'd like....

I'm confused. Why would you guys run 0w oil when the manual ('01 pg 148) suggests running 10w-40, 15w-40, or 15w-50 for ambient temperatures generally higher than 50f/10c? Regarding the mixing of oils, "all current engine oils are compatible with each other, ie when making an oil change it is not necessary to flush the engine if you wish to use a different brand or grade of oil. Since however each brand of oil has a special composition, you should, if possible, use the same oil brand if it becomes necessary to top up between oil changes."

Update: It looks like some Mercedes dealers in the US may stock and can order Mobil 1 5w50 by the quart; the part number is Q1090134 ($7 per quart, the fill for the SLR).

I have one simple question here. Which Dallas dealer did DallasBoats get the thicker oil from? This may shed some light on this for me....being from Dallas.

www.avlube.com stocks Delvac 1 5w40

The Porsche store otherwise known as Boardwalk. They did the oil change. BTW, the car runs great, I'm just saying I noticed a difference. I don't feel all that uncomfortable about it since the manual suggests the viscosity anyways. Although, maybe it was changed because of failure data, that would suck for me. I'll still probably remove in the next few thousand miles anyway. I like the free revs from before........................ maybe that will blow my motor...........................

what do those racing 996's (ie grand am cup cars, but NOT GT3 Cup cars) use for motor oil? that'd be a good example of waht to use for high speed purposes

Here is what Joel Reiser had to say on the subject in a post on the PCA Club's site. Joel is the PCA's technical editor for the 996 as well as certain other Porsche models and he also works in the business(I believe he owns a racing shop specializing in PCars). I would certainly take his advice over many people on this site. <<<<"These are basically the same recommendations as before. And, as before, your 15-50 is still perfect for race cars, but still wrong for street cars anywhere but the hottest of climates. The 15-50 is just too darn thick, and the hydraulic lifters won't pressurize when the engine is started & run cold. In many cases, the engines will be down on power, will be low on compression, and will usually make significant if not alarming ticking noises. If that happens, and you know the oil is clean and the level is correct, just drive it real easy til it quiets down, and change the oil if the weather does not get a whole lot hotter really soon. However, if it ticks like crazy, and the oil level is too low, or too dirty, don't drive it at all, just have it corrected first. So, back to your specific case, I would suggest dropping it down a grade for weight, to the 0-40 or the 5-40, or try one of the other approved brands. Joel Reiser - PCA WebSite - 4/16/2003">>>>

dude, just put him on ignore and move on just look at his posting history, from the very beginning, and you'll see why he has been put on my ignore list.

I think for most of us here who don't track our cars hard the higher weight oil is really not necessary... if your racing and going out to the track every weekend... well that's a different story... the 0W40 or 5W40 would suffice for most people...

What about 10 W 60?

http://www.performanceoilnews.com/oi...nst_oils.shtml if you look at the Castrol 10W60 it is one of the oils that experience viscocity loss in the test above... it's particle size on the metal wear test was also worse than that of the mobil 1 (0W40 and 5W50) oddly enough though it did generate good hp at max rpm... I'd pass on the castrol because it is not a fully synthetic oil like Mobil 1 or Amsoil (this is documented) and Mobil 1 or Amsoil will definitely have longer service intervals.... if your one of those people who change their oil every 5000 miles then it's ok... I wouldn't leave the castrol in their for any longer though...

Actually the Castrol 10w60 is a very different breed than the Syntec we get here in the US...I believe the 10w60 is a fully synthetic PAO and/or ester base.....it's good...for BMW's, not Porsche....

How would that effect valve wear?

Hey DallasBoats. I was at the Porsche store today to get oil change stuff for my car and discussed the oil. The 15 - 50w they have in the parts department is for the 964 and 993 cars according to them. They are suppose to only be putting the 0-40w in the 996's. I don't know who put it in but this is not their policy as the parts department and shop manager have both told me to use 0-40w. FYI I am running 0-40w in Dallas heat with no lifter noise?

Steven is right. In Dallas, Boardwalk Porsche, Park Place Porsche and Ruf Autocentre all normally use and recommend 0W-40 for 996's.

Hi, I do not want to hijack this thread nor appear to be an "expert". However I am qualified enough to pass the following comments 1 - A 0w-40 or 5w-40 oil is what is prescribed by Porsche for your car. The 0w-40 viscosity can be used in all temperatures but the 5w-40 viscosity should be only used above -25C. There are very sound reasons for these oil viscosities. Only one SAE50 oil is Listed by Porsche - it is M1 5w-50 which is not available in NA. A 15w-50 lubricant should not be used except in special track circumstances The viscosity recommendations are well covered by Porsche Service Bulletins and in their Approved oil List On that List there are; 17 - 0w-40 viscosity oils listed 81 - 5w-40 viscosity oils listed 1 - 5w-50 viscosity oil listed (M1) 2 - 1999Porsche911 - you have it wrong - see 1) above! As well, the very reason why you say not to use a 0w-40 oil is but one of the reasons why Porsche Approve, List and recommend that viscosity! 3 - As Brant suggests, you can mix the like versions of M1 to give the ultimate viscosity you want. However for normal use it is possibly an overkill unless regularly tracking the vehicle. M1 0w-40 is a very sophisticated lubricant - probably one of the very best made at any price - I woild not mix anything with it! Delvac 1 5w-40 (or M1 Turbo Diesel 5w-40) is better not mixed with another product either as it has a high ester content and this will be "wasted" in the process 4 - Castrol's RS 10w-60 is an excellent product but too viscous and has not been Approved by Porsche for this reason. It may be suitable in some race/track circumstances where fuel dilution could be an issue. It is regularly available here in OZ and in Europe I had a hand in developing this wonderful product here in OZ from its introduction in the late 1970s. It was initially a full ester based lubricant with the characteristic "caster bean" odour like Castrol R30 and etc! I used it for many years in a wide variety of engine types - flat, vertical, horizontal vee, aircooled, water cooled, diesel and petrol 5 - GSIRM3 - there are very sound reasons why the valve train is affected by oil viscosity. INA-Schaeffer and other valve train component makers have researched this issue at great length I could cover this and other viscosity related issues in some depth but it would be boring for many In short use a lubricant that Porsche Approve and List - do it with great confidence! I hope this post is seen as contributing to knowledge on lubricants and lubrication Regards

Doug, You can pickup Mobil 1 5w-50 at Mercedes dealers in the US; the part number is Q1090134 ($7 per quart, the fill for the SLR). That being the case, is 5w-50 a better choice than 0w-40 or 5-40 for warm climate driving? It it worth a $2 premium per quart for 5w-50? My car burns about half a quart of 0w-40 every 1,000 miles. Wouldn't going to a thicker oil help prevent seepage and burn-off? For warm climate driving, isn't 0w-40 the same as 5w-40? The first number is for cold temp and the second number is for heat temp, right? Then the only difference for warm weather driving is if you go up to 50, right? If so, then isn't 5w-50 the same as 15w-50 in warm climate driving?

Hello, Cydog - yes the first designation is essentially the cold start performance of the lubricant. The 5w-50 is not a better choice but simply an option. Delvac 1 5w-40 may be a better choice! The oil's formulation helps prevent seepage and burnoff - some oil top up is good for the oils additive package and allowed for in some engine designs Actually the M1 5w-50 and the M1 15w-50 are similar at around 100C but between the cold start temp and there is a different story! Stay with a 0w-40 or 5w-40 lubricant unless you intend to track the vehicle regularly Regards Doug

Great info Doug .....and for those of us that have our 996 as a daily driver but ALSO track it about 1 weekend event (DE) every month?

[QUOTE=Doug Hillary]Hi, 5 - GSIRM3 - there are very sound reasons why the valve train is affected by oil viscosity. INA-Schaeffer and other valve train component makers have researched this issue at great length I could cover this and other viscosity related issues in some depth but it would be boring for many I understand how some parts of the valve train could be impacted by oil viscosity changes, but the post I was referring to mentioned the valves would be effected. I don't see how the valves themselves would be effected.

[QUOTE=GSIRM3] Too thin an oil can lead to excessive bleed down in the lifters. This can cause looseness, causing the lifter to move up and down while not centered. Having an unprimed lifter can also lead to poor idle since valve are not opening and closing properly. Priming of a lifter is not a few second process.

Thank you Doug for your time and input. Your post is of the type that makes the Rennlist the incredible resource it is.

..

My son's old 80cc 2 cycle aircooled kart engine was run on 100% castor/premix. Brings back fond memories...... Now his 125cc water cooled runs on only synthetic. Thanks for all the oil info.

itc, I raced MX in the 70's and used castor bean oil. It did have it's own unique aroma. And for those of you that complain about stock shocks you should have experienced the Girling MX shocks of the 70's. As to this threads content I have Redline 5-40 in my car.

As Doug said Mobil 5w40 Delvac may be an excellent option in warmer climates. However it is significantly thicker than 0w40 at 0�C, 601 VS 1066 cSt. Delvac 1 is exactly the same as the old discontinued "Truck and SUV" Mobil 1. For marketing reasons they changed the name to "Turbodiesel Truck". Its available here in Texas at O'Reilleys auto parts for $5.59. Beware that Mobil now sells "Truck and SUV" as a 5w30 oil that is not a high performance oil. Comparing 0w40 VS 5w40 Mobil 1 the 5w40 is significantly thicker at low temperatures, has more antiwear additives, and less viscosity index improvers. The 5w40 looks like an excellent summer or track oil. Here's a viscosity chart I found, it's a couple of years old.

Here's a viscosity calculator. http://www.shellglobalsolutions.tesh...ending_pop.asp

Hello, LVDell - Either the 0w-40 or 5w-40 viscosity of a Brand that is Porsche Approved and Listed will be OK I prefer an oil with a High Temperature High Shear (HTHS) viscosity above that specified as Porsche's minimum (3.5cSt). M1 0w-40 has 3.6cSt and Delvac 1 5w-40 is 4.1cSt. This is measured at 150C. Mr Baker's suggestion is wise if longer events are your lot! Itc - thank you for publishing the "List". I have difficulty in doing such things! GSIRM3 - the valves may suffer a secondary impact via other elements within the valve train - this is not too common 1999Porsche911 - your description misses some of the facts. A better understanding of viscosity, pressure and flow, and the impact of various forces on/within a modern valve train may help. A lubricant that is too viscous is much less desirable than one of the correct viscosity in the operation of valve train components An SAE40 oil (0w-40, 5w-40) is not a "thin" oil by any standards. For instance in MY1941, the oil recommendations for American engines were the monogrades SAE10, SAE20w, SAE20 and SAE30! Some engines required SAE40 above an ambient of 90F!! The most common grades today are "multigrades" with miximums of SAE20, SAE30 and in Europe, SAE40! SAE50 is often called a "thick" oil The first 20w-50 multigrade oil was especially produced in 1958/9 for the BMC Mini - which had an integrated engine/gearbox and lubrication "difficulties"! 10w-30 multigrade oils were introduced several years earlier In modern (and most) engines it is desirable for the lubricant's viscosity to change as little as possible from say -10C to 50C. This is why a 0w-40 lubricant appears so "thin" at ambient - it may appear to be only a little different at 100C - this is what is needed! That is by design!! The higher the Viscosity Index number the better. Note from Mr Baker's post #53 that M1 0w-40 has the highest number (187), of the oils in the prescribed 0w-40/5w-40 range! The CAF� requirements in NA are the prime reason why 0w-20, 5w-20, 0w-30 oils are used as factory fill by most car engine manufacturers there. No excessive wear problems have been encountered when the thinnest of these oils have been used in suitable engines as mandated These viscosities are totally unsuitable for use in Porsche engines! Mr Baker - thanks for contributing your expertise, and thanks Russ for your comments

Thoroughly appreciate your time to shed some light on this issue for us!

Thanks Doug...it is refreshing to read your posts.

Here are the specs for Mobil 1 5W50 http://www.imperialoil.ca/Canada-Eng...il_1_5W-50.pdf and here are specs for Mobil 1 "DELVAC" http://www.imperialoil.ca/Canada-Eng...1_Delvac_1.pdf

Hi, c70Pete - thank you - pleased to see that you are interested The Spec sheet for 5w-50 is probably the lastest as it is at the API's "SM" (the latest) quality rating The Spec sheet for Delvac 1 5w-40 is three formulations old (shown as CH-4/SJ - now CI-4+/SL, was CI-4/SL) The major formulation/performance changes are quite significant. The Pour Point is now -45C, the cSt at 40C is now 102 and at 100C now 14.8. Its TBN is now 12 Its HTHS viscosity is still at 4.1cSt Sometimes formulations vary from country to country. Most M1 and Delvac products sold in OZ are sourced from the USA Thanks again Pete Doug

my pleasure Doug... I'm glad to see we can bring some deep insight into the different Mobil 1 oils.... interesting to see how the 0w40 has a higher viscocity index than either the Delvac and 5W50.... I'm currently using 5W50 but I think that is overkill since I don't track the car much... I'll be switching back to 0W40 on my next change... the car does rev a bit faster with 0W40... I don't think you can make a bad choice with any of these oils as long as you keep regional conditions in mind... and that being said even 5W50 and Delvac will perform in winters as low as -25 Celcius...

You guys have me convinced as well. I'm switching back to 0W-40 when I service the car this fall.

This is a great old thread! Thanks everyone for all the input.

Walmart now has 5w40 Mobil 1 TurboDiesel Truck available.