0w40 vs 5w40

I know there's a hundred threads about oil; nevertheless... '03 C2 with 60K miles, only driven above 40 degrees, and it usually sits for at least 4 days between starts. Engine runs great; no smoke at start up, little to no oil being burned over time. 0w40 or 5w40?

Don't use Mobil 0W40. 5W40 and 5w50 oils that are A40 Porsche approved are good till -13 degrees F.

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Can you explain why, please? Is there a difference between Mobil 0w40 and 0w40 European formula?

Please read the multitude of oil threads for in-depth, to the extreme, discussions.

Shearing.

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I've read many of them (here and other sites). After a while, after reading conflicting opinions/evidence, my eyes glaze over. Thanks. I had not read about HTHS before In my case (change the oil once a year, less than 2000 miles), I believe 0W40 is just fine, even with the lower HTHS number.

My local Indy runs a dozen 996 race cars along with a large everyday driver Porsche shop. Has for years. He swear by 0W40 Mobile One. He is highly regarded engine builder and has a ton of experience. Not as much as Jake but I trust him. I have run 5W40, 5W50 and moved around from all the top oil companies using Black Stone for 7 years now. No significant change. After my clean bill of health and IMSS install I went back to 0W40 for my SoCal low mile ride. There are so many opinion on oil, IMSB, Water Pumps, Low T., etc... Will oil save your 996 from the 20 or is it 30 now failure modes? I am sure someone will swear by the virgin, middle east, garden of eden super special brew only important for a small group of owners. For most, my guess is Mobile 5W40 will do.

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Yes, oil seems to be like a religion for some people. I get the impression anything Porsche approves is just fine. For specific uses/mileage/environments, I'm sure some are better than others. But at some point, it's an exercise in splitting hairs.

As I will show you I am a retired tribologist. A lot of shops said liquid moly. When I worked the best off the shelf synthetic engine oil was Mobil 1. Anyway, I personally spoke with Mobil and had to get to the 3rd level technical service level, I spoke to a tribologist like myself. I am running Mobil 1 European on my car for the following reasons, 1. TBN 12.56 average ( that�s an indication of detergents and dispersants in oil) and how many acids it can neutralize.2. My car with 41 service records 40 of them at Porsche dealerships so you know what they used. 3. 70 percent of wear happens at start up. You want flow not viscosity. When you start your engine you are in the boundary lubrication regime( metal to metal contact) as long as your engine low oil pressure light does not come on you are fine. 4. The w on the viscosity grade means winter, to get a 0, 5, 10 w etc you need to run some tests, one is pour point which basically indicates lowest temperature at which oil would flow. Second is CCS ( cold crank simulator) temp at which engine would start and oil would flow, before anyone give me any bs I can explain the whole thing. (HTHS) High temp high shear has to do with permanent shear of VI. Unless you are tracking your car and really abusing it I�ll stick with Mobil 1 European. 2. I would never put Liquid moly on my car and Three I used to formulate motor oils, any questions please come. Finally you can buy it at Advance, Autozone and get a Bundle with even the cabin air filter. For those that weary at viscosity decrease those cars are probably diminishing lubricant viscosity by running reach (too much fuel).

Some proof.

Proof.

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Thank you. The explanation above gets me back to my original post: for a car that is being started after sitting for several days, and at a temperature of at least 40 degrees F, is there any difference between 5w40 and 0w40? In terms of getting the oil flowing quickly? Thanks.

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Either one is fine, doesnt matter

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Yes there is a noticeable difference. My indy who did the first oil change because I took the car to his house since I wanted to fix a few other things and I wanted to meet him noticed and commented about it quickly. If you don't specify, in the shop he works at which is a PCA shop they use 5W40 liquimoly, on higher mileage cars with some oil consumption they use 10W50. If you go to the 0W40 you will see the difference on the gauge right away. 70 percent of wear happens at start up because you are dry, also at idle you have what is called mixed film lubrication (some metal separation, some metal to metal contact), don't idle the car, never use drive thrus if you want to keep your car going a long time. stick to one oil. oil is the lifeblood of the engine and if you do frequent oil changes you are just using it as cheap insurance. measured viscosity is a range of numbers so not all Ows oils will flow exactly the same. If you want to compare oil flow, look at CCS numbers for same viscosity grade. viscosity is defined as a fluid resistance to flow, now you have newtonian fluids and non newtonian fluids. Hope this helps.

Always a good conversation. I'm running 5w40 Liquimoly. I am choosing that brand because of reputation, Porsche certification (A40), and because of the FCP Euro warranty. Prior to discovering FCP I was running Mobil 1. This discussion makes me think I should switch over to 0w40. However, even here, there are opposing opinions. My take away is to use a high quality oil and change it often. Best,

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my issue with liquid moly is low TBN, you can disperse less contaminants, more than likely dirtier engine and you can neutralize less acids. Also, I like it being available at the parts store. One final thought , if anyone knows please come forward. What�s Liquidmoly Zinc Phosphorus PPM content? At what price are you buying the 5 qts. Mobil one , I paid $37 plus tax but I got cabin air filter, plus oil filter.

Isn�t 5W-50 the recommended oil weight?

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Not according to this, which I believe is the most recent list provided by Porsche: https://static.nhtsa.gov/odi/tsbs/20...66908-0001.pdf Now, if you have a high mileage engine or very warm environment, maybe it's ok? But I'm not an oil expert.

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🤷‍♂️ A note from the list you posted 🤷‍♂️

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This is their new recommendation as I stated before is a band aid for higher oil consumption and bore scoring. Help you nurse them out.

My concern with many of the recommended oils for ours cars and after lots of reading which sometimes is over looked is the high calcium content . I have been using Liqui Moly for sometime now in my car and I will be changing it out to try Motul X-Clean along with some MoS2 My 997.1 even with 94 octane fuel will exhibit a millisecond of LSPI in higher temp under light load lower rpms conditions (unavoidable slow traffic city driving) which is very common with direct and also non-direct fuel injected cars. There are lots of articles that suggest the byproducts of such oils not only contribute to LSPI also leave behind excess deposits that are not beneficial to our engines. At my last oil change I added Ceratec with the Liqui Moly and it did help with the LSPI although not entirely. Many articles are now recommending to use a low or mid calcium Porsche approved oil and a high moly content to deter the above mentioned. I am going to try this route along with the Mid-Saps oil to see if any improvements are noticed ? as for 0w40 vs 5w40 and above zero the flow characters benefits between the two are minimal at best.. 2 of one or one of the other ....

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Is there a problem using the Porsche recommended 5W-50 if you�re not experiencing high oil consumption or symptoms of bore scoring? What�s your experience working on the M96 engine?

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First question. I�m a newby in regards to the M96 engine. As previously explained I�m a retired tribologist, used oil analyst, oil formulator, business manager oil salesman , trainer etc. I�m not an engine builder or mechanic. Now these applies to all engines , when an engine is design there are certain clearances, tolerances that the engine has. The manufacturer chooses recommended viscosity grade based on that, as you can see this is a highly technical community and there is a wealth of knowledge. Anyway for years Porsche recommended 0W40 Mobil one is not until 2019 when a flood of bore scoring is going on and they up the viscosity grade to a 50 weight oil. If your car doesn�t has issues and you choose to run the 5w50 I�ll guarantee you the following 1. At start up you are going to have some more wear than when using a 0w and that will be every single time you start it, 2. You are running an oil with more viscosity at full film lubrication (the oil film completely separates the parts and there is no metal to metal contact) that�s not at idle and maybe someone in the community knows what rpm number we are talking about you are going to have more friction between the oil molecules therefore more heat. There should be an increase in oil temp. Your fuel economy will be less. For the guys interested in power less hp, less torque, I�m sure about this but I�m not certain about what that number is. We used to do special racing oils for among others Mark Martin (Jack rouse racing), Jeff Gordon (Hendricks Motorsport) , etc, and if you know the Porsche history many many years ago Porsche used Valvoline, when they brought a car here to the United States and drove it all over the country. Anyway you tested all of those in engine dynos, I don�t have access to one of those now. I guarantee you if we track the exact same car with the exact same engine I will out accelerate you with a 40 w oil compared to a 50w oil. Now in the past when engines were starting to wear out people would just increase the viscosity. Which is exactly what Porsche did. I tell you not, Valvoline Max life first formulated motor oil for engines over 75,000 miles and now every one has a higher mileage engine oil, higher mileage fuel system treatment, transmission treatment etc. I can explain a lot more about that because I was in the technical team where this was developed at. In a nutshell you didn�t have to change the viscosity you have to change the type of oil that you use. Based on what I have seen no one has a 0W40 formulated for higher mileage engine Porsche spec etc. as I stated before I contacted Porsche directly and they did not reveal anything about this oil. A good example would be to run brand new locasil engines with both oils on engine stands at controlled conditions let�s say an accelerated 50,000 mile test. Then open the engines up, rate the parts for wear, deposits, scoring, sludge etc, as it is done to certify API oils in NA and ACEA oils in Europe. Porsche does not blends any lubricants, two I would be weary about Mickey Mouse oil company coming in with a special product. 100 percent disclosure I�m a XOM and bigger yet VVV stockholder. As a matter of what I have increased my XOM position because of the dividends and the fact that at one point in the last year the stock was at 50 years low and was taken out of the Index DJ.

Thanks Is there any benefit of running the Porsche recommend 5W-50 in a 23 year old 996 with 75K? It sounds like unless you have bore scoring or high oil consumption you�re actually harming the engine 🤷‍♂️

5w50 is too high ... 5w40 with a moly additive is where you need to be ..Countless 997 / 996 owners have engines purring like a crate of sleeping kittens with no issues.

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Are you talking about moly disulfide in the formulation or a moly top threat? If so which oil brand, etc let me know. I�ll stick with 0w40 for the reduced start up flow time.

Wandering into another oil thread

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What do you think about Motul's 0w40?

Don�t know much about it? My wife�s amg and now the Porsche call for this viscosity. I�ll look into it. A detailed spec sheet will show a lot about how this oil is made up. I had this haze IPA on Saturday at the car show so I�m with my dog right now trying to drink and buy some. She found her long lost son. She is 17 chihuahua rat terrier, no teeth, but she likes beer and all the smoke or grill meats I cook. Cheers. I love ❤️ the people out here in Texas.

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For what it's worth, my indie used Motul 5W40 when he changed the oil in my car a couple years ago. Only one data point, but he seems to know his P cars.

Quote: Are you talking about moly disulfide in the formulation or a moly top threat? If so which oil brand, etc let me know. I’ll stick with 0w40 for the reduced start up flow time. Liqui Moly MOS2 additive as the vast majority of A40 approved oils do not have higher amounts of Moly in them alone .

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sounds like Dan from Speed Gallery?