'86 K75C oil analysis

I did an oil analysis on my newly acquired K75C. The bike was serviced last November. I do oil analysis reports on all my vehicles to determine the health of the engine, check the specific oil in use effectiveness in that application, select a different oil if needed, etc.. IMHO if you don't do oil analysis in your application you have no idea how well that oil is performing in that particular application.

I was quite surprised to see that Castrol 20w50 in only 1450 miles had sheared to nearly a 30 weight - 12.61 cST @ 100C. Since I suspect the Castrol used was a non synthetic by the cost on the service receipt, I expected some shear but not nearly 2 grades. As I wrote in my post on www.bobistheoilguy.com I'll be switching to a shear stable synthetic.

I know a lot of you high mileage guys use Castrol and I'm only posting this as a FYI and am not bashing Castrol or your choice of using it. SO DON"T KILL THE MESSENGER. To be forewarned is to be forearmed.


Here's the oil analysis results: http://www.bobistheoilguy.com/forums/ubbthreads.php?ubb=showflat&Number=1706112#Post1706112

VISCOSITY @ 100deg C
SAE GRADE RANGE (cST)
30 9.30-12.49
40 12.50-16.29
50 16.30-21.89

http://www.bobistheoilguy.com/index.php?option=com_content&view=article&id=48&Itemid=55

You can compare yours to mine:

http://www.eilenberger.net/K75S/C21138.pdf which indicated the Mobil-1 (auto grade) 15W-50 (incorrectly listed as a 15W-40 on the report) - that the Mobil-1 oil at 6,000 miles would be fine for quite a bit more use.

Guess it's a case of you get what you pay for sometimes..

So, are you saying the Castrol 20/W50 will result in premature failure and the Mobil 1 won't ?
Or maybe you're saying the Mobil1 will result in a later/no failure than the Castrol 20/W50.

Just what is it ?

Acejones said:

So, are you saying the Castrol 20/W50 will result in premature failure and the Mobil 1 won't ?
Or maybe you're saying the Mobil1 will result in a later/no failure than the Castrol 20/W50.

Just what is it ?

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None of the above. Just giving out some data. Draw your own conclusions. Anything else leads to an oil-war, and as moderator - I will shut down an oil-war thread immediately.

I agree. I really don't understand why any of this oil stuff gets posted anyway.

deilenberger said:

None of the above. Just giving out some data. Draw your own conclusions....

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Correct.

Acejones said:

...I really don't understand why any of this oil stuff gets posted anyway.

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As I stated in my original post that it was a fyi for those that might be interested. It might be useful or it might not. Also: from my post on bobistheoilguy see the link in the original post.

"I don't know if the BMW engineers knew this would happened in this engine and specified a starting viscosity of 20w50 knowing the engine would be fine with a near 30wt viscosity after the initial shear."

There are a lot of unknown variables such as exactly which Castrol 20w50 was used (auto, motorcycle, dino, synthetic), was 10w40 used and not 20w50 even though the service receipt says 20w50, was there any makeup oil and what viscosity, etc. etc. The only conclusion that can be made is a supposedly 50 weight oil sheared to 12.61 cST @ 100C which is only .13 cST from being a 30 wt. Check the BMW Motorrad recommended engine oil viscosity chart and see what temperature range a 30/40 wt oil should be used and as deilenberger says draw your on conclusions.

I had no intention of starting an oil war or bashing one brand of oil or those that choose to use it. Just giving out some info for those that might be interested. Matter of fact I use a German Castrol Synthetic in my Audi 1.8T and get outstanding oil analysis results and have a stash of at least 100 qts of that specific "Green" formulation oil.

gawa bot- thanks for the information.

Posting oil analysis is good stuff and shouldn't start the dreaded "Oil War."

Ragman

Thanks ragman and deilenberger.

I'll be posting the next one in a year. I'll be interesting to see how the Amsoil does. If it doesn't perform well then I'll try another oil. I'm not brand loyal and am only interested in getting the best performing oil for what ever application I'm using it in. The only way to find that out is through comparative oil analysis of various oils in that specific application.

I think we take the oil thing far to seriously. I think you will have no problem when you use any oil of the recommended viscosity and classification. I know of people who swear by the brand of oil they use because their vehicle have gone many miles without problems and other folks who went just as far with no problems by using whatever was on sale or handy and didn't stick with a brand. When I sold a friend my K75RT, I forgot to tell him what oil to use and after two years, I found he was running 10W30 dino oil and had had no problems. It's been 5 or 6 years since then and he has been fine. I think the brick is an automotive engine laying on its side anyway.

I'm not aware of anyone that has had an oil related failure in any kind of vehicle when the oil was changed as specified with the specified oil.

osbornk said:

I think we take the oil thing far to seriously.

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Agreed. It's almost a religion. That's why I said don't kill the messenger.

Given when the brick was designed and I doubt at that time there were any really good shear stable oils, I bet the engineers did as I suspected and specified a recommended viscosity with it's sheared viscosity in mind. But when I saw a 2 viscosity grade drop in the brick that doesn't have a shared transmission sump, I though it might be important to some to share my results.

I'm pretty particular about the maintenance of my vehicles and oil analysis in one of those things I do. It can in fact save you money. As an example I've got a '93 Mazda pickup with 294K miles I've owned since new. I've used Castrol Syntec and Mobil One in it most of it's life. I saw some oil analysis reports of the budget dino Formula Shell oil that were really good. For fun I ran a 5K oci (oil change interval) in my truck and lowe and behold the oil analysis numbers were as good if not better than the Mobil One synthetic. So I switched to Formula Shell dino and am saving $$ every oil change. But I wouldn't have know that for sure without an oil analysis.

osbornk said:

I'm not aware of anyone that has had an oil related failure in any kind of vehicle when the oil was changed as specified with the specified oil.

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Well... I could tell you about back in 1966 or so, I owned a '61 Volvo PV544 that didn't like Esso oil (took out a ring after adding a quart..)

But a more recent example - from BMW - is the S54 "M" engine. Started out life using BMW 10W-30 synthetic. That quickly led to camshaft failures (fracturing of the hardened cam surface due to film breakdown), and to BMW getting together with Castrol-EU to design a specific oil for the M (Castrol TWS 10W-60, made in Germany, and probably going in my R12R once I'm out of warranty.)

It happens - it's rare but it does happen. I believe some recent Toyota models had problems, bad problems with sludging of oil (ending in engine failure) if the recommended oil was used for the recommended change interval.

deilenberger said:

It happens - it's rare but it does happen. I believe some recent Toyota models had problems, bad problems with sludging of oil (ending in engine failure) if the recommended oil was used for the recommended change interval.

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Same with the Audi A4 / VW Passat 1.8T. Due to the engine being mounted longitudinally that because of a cross member limits the oil capacity to 4 qts. folks that neglected to use the VW 502.x spec'd synthetic oil, extended the oci beyond the recommended 5K, and neglected PCV system got some nasty $$$$+ repair bills because of sludge induced engine failures.

Given that I run a very specific German made Castrol Syntec in my A4 1.8T that I've verified its effectiveness with oil analysis on multiple occasions. That particular turbo engine is really hard on oil but that oil does not shear and gives wear number so low in a 5K oci at times it's hard to determine if they are from actual wear or the background element numbers in the virgin oil itself. But that specific oil doesn't give standout low wear numbers in all applications hence the need to verify with an oil analysis. Just do some searches on www.bobistheoilguy.com and look for GC 0w30.

So given that history, and the K75 normally operating at 4K+ rpm all the time, a few bucks for an oil analysis is IMHO money well spendt for the peace of mind that you know from objective analysis how well your oil is doing.

deilenberger said:

It happens - it's rare but it does happen. I believe some recent Toyota models had problems, bad problems with sludging of oil (ending in engine failure) if the recommended oil was used for the recommended change interval.

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It wasn't an oil problem, I think it was oil temperature (thermostat) and crankcase ventilation issues that caused the sludging. My son-in-law had (and still has) one of those things. He changed oil every 3,000 miles and it locked up at 140,000 miles. This was before Toyota acknowledged a problem and were blaming lack of changing oil for the problem and denying all claims. He bought a used engine with 100,000 miles on it and is still using it at 265,000+ miles using the same oil with the same interval. I bought his Toyota pickup of similar vintage with 170,000 miles on it and the last time I talked with my cousin who bought it from me, it had well over 200,000 miles on it with no problems. Same engine with the same oil and change intervals.

osbornk said:

It wasn't an oil problem

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Dunno exactly what you consider an "oil problem" - but I'd consider lack of circulating oil and subsequent engine seizure an oil problem. Caused by the oil? Perhaps not, perhaps another fault in the engine, but still - lack of lubrication to me equals an oil problem.

YMMV, but bet not a whole lot..