Blackstone oil analysis

Looks like I'll be doing oil changes myself in between the dealer services until the results improve.

Thanks! I'm planning on changing the oil at 7k as well.

Thanks for posting your results. Mine are below for reference. Your lead numbers would make me nervous too.

It would be nice to get more data from other folks collected. As you mentioned, doing the minimum oil changes is not a good idea at all.

That first lead number looks sky high, especially compared to the 2nd sample.

What moving parts have lead inside our engines? Just the 5 crank bearings? Curious. Thx.

Didn't you have a 335 before Jon?

sparkyg wrote

Didn't you have a 335 before Jon?

Not I.

Ok, I just remembered the Blackstone postings before on E90post.

No sweat. Thx.

The analysis is a great idea. The factory change frequency is rubbish to say the least.

sparkyg wrote

Ok, I just remembered the Blackstone postings before on E90post.

No sweat. Thx.

The analysis is a great idea. The factory change frequency is rubbish to say the least.

I'm starting to wonder what the oil sensors are looking for when it gives a recommended change interval. Is it testing for some kind of foriegn content or just viscosity?

808MGuy wrote

I'm starting to wonder what the oil sensors are looking for when it gives a recommended change interval. Is it testing for some kind of foriegn content or just viscosity?

I don't think it is actively sampling the oil at all to suggest the change interval.

I think the interval it suggests is based on fuel burn. That is the parameter that the pre-E9X cars used. Burn a lot of gas or do a lot of city driving, and you get shorter intervals.

The GM way had something to do with measuring the capacitance of the oil, but I don't think the BMW system works like that.

No current car has any kind of oil 'sensor'; it's just an algorithm; that's why you have to reset them . Each manufacturer uses different criteria: ignition cycles, fuel usage, along with average speed, duration, mileage, etc. But all are just a guesstimation at best.

AFAIK, only some big trucks have oil sensors, but even those can only measure viscosity, not contamination, additives, etc. To me, changing oil every 5 to 7.5K miles on a high-performance engine is cheap insurance. Also worth noting is BMW used to recommend changing oil every 3K miles, but when they started paying for oil changes, that was conveniently raised to 15K miles . Good day.

elp_jc wrote

No current car has any kind of oil 'sensor'; it's just an algorithm; that's why you have to reset them . Each manufacturer uses different criteria: ignition cycles, fuel usage, along with average speed, duration, mileage, etc. But all are just a guesstimation at best.

AFAIK, only some big trucks have oil sensors, but even those can only measure viscosity, not contamination, additives, etc. To me, changing oil every 5 to 7.5K miles on a high-performance engine is cheap insurance. Also worth noting is BMW used to recommend changing oil every 3K miles, but when they started paying for oil changes, that was conveniently raised to 15K miles . Good day.

Just from my visual inspection of the oil that came out, I thought the oil was pretty clean. Definitely not black and dirty but the numbers on this report show that maybe a shorter interval is something to look at. I'll just wait and see what happens with the next oil change which will probably be in 5 months or at 15k miles.

These results are consistent with others I have seen posted here and over on Bimmerfest. If anything, this reinforces the fact that the recommended oil change intervals are too long.

What are the negative effects of running the car for another 7.5k miles (to the 15k mi mark) with that much iron/lead in it? Would it reduce the life of the engine?

MrHarris wrote

What are the negative effects of running the car for another 7.5k miles (to the 15k mi mark) with that much iron/lead in it? Would it reduce the life of the engine?

I'm wonderin this as well. I went with the recommended interval for my second oil change - after the 1200 mile service, I did not change the oil until the car told me it was due at 15000 miles. Hope the potential long term damage is not too bad. I'm definitely doing an oil change every 7500 miles from now on.

I paid for my oil change at 7K miles. Contamination in the oil causes extra wear on the cylinder walls so loss of power would be an eventual consequence. I'm not an expert so I can't say by how much or how long it would take for the particulates to wear down the cylinder walls, if ever. I just feel better with clean oil. Cheap insurance is right if you're keeping it for 10 yrs. Low viscosity oil should sneak in to the combustion chamber and cause more oil burn, possibly fouled plugs and loss of power. This is a high compression engine so I don't like the sound of low viscosity oil as it can be pushed up to the chamber. Just change the oil yourself. Not a big deal.

Eliminator wrote

I paid for my oil change at 7K miles. Contamination in the oil causes extra wear on the cylinder walls so loss of power would be an eventual consequence. I'm not an expert so I can't say by how much or how long it would take for the particulates to wear down the cylinder walls, if ever. I just feel better with clean oil. Cheap insurance is right if you're keeping it for 10 yrs. Low viscosity oil should sneak in to the combustion chamber and cause more oil burn, possibly fouled plugs and loss of power. This is a high compression engine so I don't like the sound of low viscosity oil as it can be pushed up to the chamber. Just change the oil yourself. Not a big deal.

For the record, my car did not burn any oil since day one. I never had to add oil between services.