UOA: Mobil 1 5w-40 down to 30 grade after ~1200 miles

Bought a 99 C2 with 129k on the clock in early Dec 2022. I immediately had to up on jack stands for a few weeks to take care of some overdue maintenance (AOS, oil cooler, spark plugs, tubes, coils, belt, and pulleys) Before I changed the oil for the first time, I took a sample and sent it in for UOA. I have no idea what brand of oil was there previously, but the PO didn't change the oil during the pandemic (and service records on Carfax confirm that). So I changed the oil with 5w-40 Mobil 1 and have been driving it for ~1200 miles. I did another UOA (using a pump through the dipstick -- haven't changed the oil yet) and was surprised to see the 5w-40 already down in the 30-weight grade range. So my questions: Is this normal? Expected for Mobil 1 5w-40? Anything else below that should cause any concern? From the beginning, I intended only to run Mobil 1 for a short stint before dropping the sump, checking for scoring, and then (permanently) switching over to Amsoil 5w-40. Any thoughts/opinions on that are welcome. If I'm reading this correctly, the virgin Mobil 1 5w-40's viscosity would be 13.2.

I don�t know the answer to your question but unless he said he never changed the oil, I wouldn�t go by carfax. I haven�t paid for a oil change in years and do every 3k. Good luck, I�m curious to what the gurus say.

Mobil1 is junk

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this is what you got. To make a multigrade motor oil you use a VII (viscosity index improver, a polymer), with use it will shear and you will loose viscosity. As it has been pointed out here the Mobil product will shear. What I�m doing on my turbo and early 99 I�m mixing Mobil one 0W40 with 5W50. Seems to be the perfect combination for my cars is 33 percent 0W50. My cars don�t burn oil, they don�t smoke and there is no scoring. Part of your lower viscosity is fuel dilution. Make sure you run Techron or sea foam whatever you like in a fuel tank. Also buy good gas, I put nothing but shell v power 93 on my two cars.

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Thanks for the response. I guess I was just surprised to see the viscosity drop off so quickly in only 1k miles. I run Redline SI-1 regularly. ​​​​​​​ The best we get here is 91, but I only use Chevron or Shell.

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This is good stuff. Lake recommended it to me too. Highest content of PEA out there I believe.

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I think my ***** take that claim

Don't use mobile 1, used Driven DT-40. It was designed specifically for our engines. and please, never ever ever use seafoam! just keep filling up with Chevron premium, and that will do all the cleaning you'll ever need. Supposedly according to the most latest PCA video shells premium with V power is not bad either. I prefer Chevron with techron.

they developed an entire line of oil for the m96 watercooled engine?

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Missed your zingers. Going to need some Used Blood Analysis to confirm that though....

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1. Is not formally approved. 2. Who manufactures it blends it, and what kind of quality control the manufacturer has are they ISO certified. 3. How often do they calibrate the instruments that they used for quality control. 4. Overpriced as hell. 5. I�m a retired lubrication engineer and I didn�t retired at 45 by making mistakes with money. 5. Next thing you guys are going to say is for me to buy a Jake Raby FSI airbox carbon fiber that cost $3000. For $175 I bought a Carrera 3.8s airbox with a kn panel liter and the fabspeed bracket. Next time you guys talk to Lake ask him what number was his cls (certified lubrication specialist) certification from STLE (society of tribologist and lubrication engineers) mine was 449, one of the first three trilinguals. A picture is worth a 1,000 words.

what does one do with that certification? A Lubrication Specialist's Core Responsibilities Evaluates and selects lubricants to use and their purchases. Conducts lube surveys. Trains lubricators and assembles work list. Develops quality assurance and used lubricant analysis programs. Troubleshoots and problem solves lubrication issues. Maintains records of all application, as well as waste collection or disposal. Requirements for Taking the CLS Exam Three years of experience working in the field of lubrication

Sas why not use seafoam it’s one of 2 cleaners Jake raby recommended

Work truck that certifies that you get lubed by a specialist is it better to give it or receive it sorry guys I had to 😜

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the exam was 180 questions, 3 hours to complete. A bunch of essay type questions. In 98 the passing rate was 30 percent. But I also worked in a new product development lab, worked with formulators, worked with race teams, I taught lubrication seminars all over the world the most weir one Osaka Japan with my Spanglish five day seminar. I also approved and monitored lubrication facilities all over the world. We had blenders in Mexico, Argentina, Brazil, Chile, etc. I would show up take a sample of a product in their respective warehouses and check if the product was within specs. Every 3 months with help from our guys I�ll cook up a mix lubricant and send it to all the facilities all over the world and they will provide basically an oil analysis telling what I just send them , guess what many times even their read viscosity wasn�t right, the tbn or tan would be wrong or the spectro on the elements was wrong. Calibrate the instruments make sure they are working up to par. I trust Exxon Mobil to provide a consistent product with far superior repeatability and quality control that mom and pop shops. I�ll seen it all.

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imagine telling ladies that you are a certified lubrication specialist. I used that line many of times in ports all over the world, with a few drinks in the system that really worked out great for me. The more different foods you try the better judge you can become about food quality if you know what I mean.

occam's razor answer: since no contamination, PO must have had a thinner oil and residual oil in the sump thinned out yours.

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Lots of opinion there, can respect that, but humor us,,,, please expand on the why. As I've got a trophy case full of wins using Mobil1, and never had an oil related failure, ever in many many decades of use. Did see a oil failure on a new girl friends VW some years ago. VW dealer called her after her car got towed in with blown motor. She called me to go down to the dealer. Dealer showed me the oil pan. it had 2" of black sludge. The crankcase looked no better. Dealer said my Gf wasn't keeping up on her oil changes. I asked her last time oil was changed. She looked at me like a deer in the headlites, said didn't know i was suppose to change it. It only been a couple years and 40,000 miles on original oil from VW factory.... Lol with turbo oil temps any oil will turn to sludge in 40,000miles in SfL.driving. Guess you like buying gas from the dictator commy state Venezuela thats now partnered with the USA more or less thru Chevron. jmho

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IPAs, Miller lite or Michelob ultra and whatever my greatest and latest bourbon blend mix is. At least it can be used as disinfectant. If you go camping you can take it with you to start a fire.

Thanks for the thoughts, everyone. I will continue as planned and switch from Mobil 1 to Amsoil.

I see similar loss of viscosity in my M3 track car with an S54 motor using Redline 50WT oil. Discussions with engineers at Blackstone and Redline indicated that shearing that much in 1000 miles is highly unlikely, and both suggested fuel dilution as a probable cause. They felt that one or two cold starts (trailer loading and unloading) after track days might be enough to cause that much dilution. I make a practice of always getting the oil in my GT4 up to temperature (>210F) for at least 20 minutes every time I start it for that reason. I have to leave sport mode off to accomplish that on the street. I have enough cooling on the M3 that it won’t reach 180F on the street without risking life and license, so I don’t try.

So ,, just anecdotal reference, I spent quite a few years playing a the track, driving for fun and crew chief for several friends ,,, The guys running German brands all had an affinity for Mobil 1 since its the "recommended oil".. What I noticed is it seemed to work fine in the classes with tight motor restrictions, IE basically stock. When you step up to cams, more injection, more more,, the factory oil recommendations go out the window. Mobile 1 racing oil does thin out quickly if your over fueling ,, which is 99% of cars running stock ECU's with a tune. (Its not the tuners fault its the analog part of the eco thats the culprit. ) What always bothered me was how fast it thinned compared to some other oils. Redline thins some but not nearly as much in 2 or three track sessions as mobile 1. Most of the savvy guys solve the problem by simply changing oil more often, in many cases I would dump the oil every day.. (2 sessions to 3 sessions max) I did this with moist oils if I could not convince the owner to get a ECU tune done to fix the over fuel at < 2000 rpms. I haven't just seen this road racing either, I handled several Sprint cars, and Hill climb and rally cars, all similar.. . Heck a 406 sprint on methanol sometimes needed new oil every session... and thats like 4 gallons.. ouch! Usually if we had a lot of yellow flag laps and the engine lost heat... Then the alcohol in the oil would go sky high.. (I have a hydrometer to check it... ) Anyway, not real favorites just observations. Although I am old enough to remember when Mobile introduced "Mobile 1 Graphite synthetic motor oil" and ended up buying a TON of engines that clogged up because of it.. LOL Every company screws the pooch at something eventually...

Mobil 1 0-40 or 5-40 is a very "light 40" to start with, meaning it doesn't take much to thin down to a 30 weight...The residual oil from the last oil change is probably enough to do this as soon as you crank it up and mix in the residual oil...( there is quite a bit of residual oil left in an M96 after "Changing oil"...).. Is a 30 weight too thin? Not if you are just driving around....but if you are going to put it on the track and realy get the temps up with hard driving I would recommend a heavier oil for sure..

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Lake at Speediagnostix said the same thing, and in his experience, it shears quickly and falls into the 30-weight range.

Oil temps should be the primary factor for oil weight selection. 10 centistokes provides the minimum amount of oil film protection for bearings. 12+ is ideal. We recommend 60w for track cars without a center radiator and 50w for with a center rad. A 60W at 250F with 10 track hours is about equivalent to a new 30w at 212f, temp at which oil are rated. Here�s a spreadsheet I put together as well as my favorite graph from Driven�s catalog. The two takeaways are oil temp is everything and viscosities are not linear.

Not to stir the pot, but aside from this report (I know there are other instances) on the thinning noted here (which seems to be from an over fueling issue more than the actual fault of the oil formulation) why do folks bad mouth Mobil 1. I am sure the over fueling issues, and other noted problems, have an effect on all oil formulations, no matter how expensive. Excluding track use (which changing every session solves, as with most oil brands), what are the factual factual issues that reportedly plague Mobil 1 oils and, in turn, negate the use of said oils in some folks opinion, in our street driven 996's? I am asking because I honestly don't know, I am not an oil expert/engineer and I am trying to understand the discussion. Everything I have read just serves to bash Mobil 1 and, with the exception of some one off instances, nothing I have read factually says it is a bad oil for our engines, especially if one is changing it every 5,000 miles or yearly (or more).

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I use it, I decided on it because my early 99 had rung all its life on it. Yes the OW40 will shear. I mix it with 5W50. I change the oil every 6 months. I�m a retired Tribologist, lubrication engineer. I used to read comment on over 500 oil analysis per month. I used to set optimal oil drain/change intervals for big fleets all over the world. For me if you are running 0w40 and wait a year to do oil changes in my opinion you are not being careful enough with your engine. If you have any specific questions just fired it up. Have plenty of it in my garage. something I do is actually check the oil for texture, smell color, I also check for intermix frequently.

FWIW, NAPA is running a sale on the M1 5W-50 for $6.99/qt and free shipping. Just ordered a supply.

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You can basically write off anyone who says x oil is better than y or anyone with an oil-based anecdote as not worth listening to.

Not all results with engines are totally scientific.. sometimes it just what it is. Not all additive packages are equal, even in 1 brand.. I stick with generally available name brands. I don't switch back and forth... I go with whatever seems to make the engine happy, as in not a ton of lifter/valvetrain clatter.. Change it often and the differences matter even less.

I use Mobil 1 Euro 5w40 in my 996 and Mobil 1 ESP 5w30 (C-30 spec) in my CD. I have always used Mobil 1 in all my cars for years (decades) and have never seen an oil related issue, so I think I'll be sticking with it for awhile longer. I do change it more frequently than required, but that is nothing new in the Porsche world.

I'm not an oil expert by any stretch of the imagination. For reference, I use Castrol Edge and change every 3000 miles based on some threads I had read over the years. There always seems to be range wars when discussing oils. I just read an article about a guy who has put on almost 700,000 miles on his 996 turbo, including about 10 track days a year. All with Mobil 1 every 5,000 miles. Yes, I know that the turbo is a completely different engine, but if Mobile 1 was so terrible would his car have lasted this long and would Porsche still be pushing it? https://www.hagerty.com/media/car-pr...out-seat-time/

Never forget that that Mobil sticker is there because "Contract with Mobil" Doesn't prove anything but that both companies have an agreement. I happen to run an oil with the right approvals, and in comparing oil pressure stability as the engine heats up it beats mobile 1 by a small margin for a longer period.(About 1/4 bar) And since I road trip my car a lot thats a small safety margin IMHO that makes me happy.

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I get it. I have no stake in the argument, just posting an article I thought was interesting. I'll bet the vast majority of 911 owners aren't members of any forums and happily follow Porsche's recommendations. Is ignorance bliss in this case? Who knows?

I don’t think Mobil 1 is a bad at all I think it’s not the right for the M96 the turbo guy with 700k miles got longevity because the car is used hard and is well cared for plus it’s a Mezger

911user with his 40AE car is almost at 500k miles on his M96 and I recall reading in one of his post that he uses Mobil1 0w40 so there is that. I don't know his change interval but it clearly CAN work. Too many folks just parrot and repeat the same old that's been said on here for years without any actual first hand experience. Sometimes we forget how big of a bandwagon a car forum can be. Choose the right oil for the job, change it often, and you'll be fine.

First hand experience is exactly the problem. Sample size too small, too many variables. Anecdotes are worthless.

Well, as long as we're talking about how bad M1 is, lets not just look at the mid level M1 products, lets go right to the top of line M1. Anyhow, if the highest sheer strength when diluted and highest level of anti wear additives are a priority for your engine, Mobil 1 Racing™ 0W-50 has much more Phosphorus@1770 ppm and Zinc @1940 ppm. Both very desirable anti sheer/anti wear additives our engines require under hard use.(like LN talks about). These high levels of anti wear additive are technically illegal on the street and with tree huggers. You'd be hard pressed to find a quality oil with more..This M1oil is also not usually available at your local Autozone/etc. But still easy to order or get at oil distributors... IMO, this is one of the best oils for hard use/racing. Its expensive. And maybe in some cases with much excess engine crankcase blow-by (or a bad AOS ?) maybe doesn't play well with oem cats. I've used it for many many years now very successfully. JMO

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Correct, Mobil does make many good products, like this one. The wide viscosity spread will result in the oil shearing to a 40wt but that in itself doesn't necessarily mean the oil won't do the job it is intended for. This is a true race oil and isn't for street use - you'd have to put it in before taking the car to the track and drain it immediately after since race oils don't have needed levels of detergents, dispersants, and corrosion inhibitors needed for street use.

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So, would you leave the motor with no oil in it or fill it with fresh M1 (whatever race oil) or use some place holder until swapping back before next event ? Hard for me to see how leaving the motor with no oil in it would be preferable to used race oil but I�m wrong� frequently.

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Well glad you agree, thanks for the reply Charles. Just to clear things up a bit, M1 0-50 & 0-30 "Racing oil does have sufficient levels of detergents/dispersents and corrosion inhibitors to not require dumping the oil charge after each race, oil change intervals are up to the engine builders recommendation, detergents/dispersents and corrosion inhibitors are not the determining factor for M1 racing oils". iirr. From conversations with M1 engineers was told the levels are high enough to allow protection for at least a few thousand miles and months of being in the crankcase. However "M1 Racing 0-50 oil is not for those that want to do 7500 mile oil change intervals once a year." Its difficult to find the exact levels of M1 Racing formula as its proprietary and not published as far as I know. Ya, they do list the Phosphorus@1770 ppm and Zinc @1940 ppm and a few other specs, but not the exact formula, I've not been able to find detergents or corrosion inhibitor levels in the past, other than they're in there. Was also told the required recommendation 'not for street, track use only' is because of the very high levels of anti wear additives that EPA says may' cause extra pollutants and can maybe wear on the cats in high blowby engines. The EPA regs have been tightened and tightened till these needed antiwear additives have almost been outlawed for the street, and only lower levels are allowed, legally. Yes, I know some small specialty oil blenders do skirt these regs with higher than allowed levels, but its illegal for them to do so and just a matter of time till they either get big enough to not chance it or get fined by EPA.... Yet, one can go to any auto parts store and buy a bottle of ZDDP additive, go figure out our EPA.... lol jmho

There should be enough data in a standard oil analysis to compare say M1 to V1 Racing, or Castrol racing, redline, royal purple, etc.. I can tell you I have spent a lot of time in the pits with pro cars and they may run the stickers, but few actually run the oil. They get wraps for their barrels in the pits, stickers on the cars,, and run the oil their engine guy says to.. Its the reason Joe Gibbs started buying& selling custom blended oil, at the track they have blends for temperature, peak rpm, etc.. All goes back to when a Nascar team used "0" weight for qualifying.. 1 fast lap and dump it.. 20 MPH faster.. Until someone figured out what they were doing, then everybody was doing it.

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yes in nascar qualifying low viscosity on engine oil, tranny and differential, after qualifying put race oils in completely different products. To whoever is running Valvoline products the oil business now belongs to Saudi Aramco watch for product formulation changes. I�m sticking with Mobil one.

Yep there even used to be a label "qualifying" oil form a couple companies, was like water it was so thin. The one other tic about various oils, the temperature that they just give up being oil. I've had cars overheat due to belt/water pump etc failures at the track. The standout oil in this case was Redline. One car ran about 20 min of a 30 min session basically with no coolant, Small track rental car 1.5L Nissan Sentra webber MSD ignition small setrab oil cooler. . telemetry showed the engine oil peaking oil temps over 300F and the oil was not burnt when I dumped it.. The head cooked it popped off the block when I pulled the head bolts.. Humped up about 1/4 inch.. Wish I had sent a oil sample off on that one ... We put another head on it, no block work and ran the rest of the season. This is nothing but a dang,,, would not have thought it would handle that that well.. kind of observation.. Personnel theory,, the higher percentage "pure base" synthetics have the highest tolerance, but haven't tested it, I suppose it could be done with a small oven.. Would be a interesting science experiment.

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there was, not sure if it is currently a spec requirement where you would basically put engine oil in a beaker cooked at 500f plus and then measured how much it evaporated burned off. A lot of the heavy duty Diesel engine manufacturers have that as part of the spec. There was a Saab turbocharged spec where the oil was exposed to 700 Fahrenheit. It�s not just measuring how much evaporated, it�s also measuring how much the engine deposits coke up. Yes true synthetics pao and Esthers have better high temperature properties, a reason I prefer Mobil one is because it�s paos and Esthers, for an example Castrol uses severely hydrocracked group three baseoils. Driven wouldn�t tell me which baseoils they use in their formulations.

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DT40 has Ester in it....I just looked at a UOA that was sent to me from a Rennlister....The Oxydation number was 40, anything over 30 means it has Ester in it... I like Ester......been using it HP two-stroke engines for over 50 years also...

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Esther�s in an engine oil formula have two functions, one is additive solubility, the other one is seal swelling, the answer to the question is are they doing using 70-75 percent group three baseoils or paos. Yes Esther�s are great oils but expensive a lot of aircraft turbine oil formulations have Esther�s because it�s extremely cold at 35,000 plus feet in the air.

latest UAO with mobil 0w40. so 'd say it does does get thinner. Maybe Ill try DT40 next time. Or just stick with this cause it seems fine.

I use Millers 5w40 Nano. Just changed it and plan to drive from Chicago to Phila and back over Easter. Curious to see what the oil test looks like after a 1600 mile trip. Haven't gone that long without an oil change since making the same trip in 2017. But unfortunately didn't test the oil then to see how it held up. But I will after this trip.

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I'd say that's a typical UOA for M1 0w40. The UOA backs up the fact that oil is marginal at best.

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I'd expect the UOA to come out really good with the Millers 5w40 Nano. Very similar in performance to DT40. Good stuff. We used to import it and sell it many years ago, but people didn't want to pay for it :-) I ended up using most of it myself.

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Thanks Charles. So far it's kept the bores and engine in good shape. But yeah, it sure is expensive.

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Who's your source? Who is your guy? Where do you buy it?

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My indy uses it which is how I started using it. But you can get it on Amazon. Millers is a UK company, but they have a US distributor. The distributor may be performance racing oils. It's big with the PCA club racing folks so alot of indy provide it.

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originally I didn�t wanted to believe the shear stability of the Mobil one 0w40, but after a while when real hot I started to see the lower idle oil pressure and that�s when I started mixing it with 5W50. I disagree that this oil is marginal. It�s just designed for fuel economy. Anyway I use it, I like it I can buy it at a good price. So use whatever you think is going to work for you. How long was the oil in the engine, ie how many months. I see from the analysis that it had 3,500 miles and you had to add one quart. Thanks