The truth shall open your eyes. Oil analysis!

[Gene in NC]

The truth shall open your eyes. Oil analysis!

Big rigs/semis go for hundreds of thousands of miles on an engine because, among other things, the internal operating conditions are regularly monitored by oil analysis and every one has an oil pressure gage..

On the other hand, we have reports of low oil pressure lights but "that's OK", and bolts falling out of m60 oil pumps.
http://www.bimmer.info/forum/showthread.php?t=22575&goto=lastpost

m20s and m30s destroying cams with low oil pressure at idle and or low speed around town driving with automatics in lockup 4th with the engine ticking over at fast idle.

Low idle speed of maybe 500 rpm in an m30. That's my bad.

I'm gonna try this oil unless engine is too noisy.

Etc., etc.

Bad enough that BMW doesn't supply oil pressure guages, but most owners have never seen one so how could they know.

Oil anlaysis can reveal what's going on inside your engine, and maybe more important, what has been going on in the vehicle that you're considering buying.

I'm just as guilty as anyone on not using OP gages and oil analysis in my BMWs, but have done oil pressure tests for diagnosis. and purchase evaluations. HOWEVER, my Banks Turbo diesel Suburban got regular oil analysis which ultimately saved my butt and my engine. So, I have no excuse. I know better.

Oil analyis is readily avaialble from CAT dealers and the like. Kit includes siphon gear and bottles for mailing samples. Easy to do and inexpensive, especially considering the alternatives.

If I had an m60 I would do an oil analysis before the next oil change. My m30 sample will go out as soon as it gets enough miles on the oil.

[Evan]

How about these guys?


http://www.blackstone-labs.com/free_test_kit.html

[califblue]

:D Simple ...I use Royal Purple 20/50 full synthic and don't drive slow...works for me:D

[SnakeyesTx]

Royal Purple FTW! :D Do you stretch the changes to 15k miles like they say you can?

[rob101]

you want the truth so here it is. Trucks use oil sampling because their sumps hold in the ballpark of 40 litres or 10 gallons of oil. as opposed to 6L or one and a half gallons of oil in most bmws engines.
so since an oil change in a truck will cost you about six times what it does for a bmw engine, ONLY in the price of consumables. it makes sense to only change your oil when it is chemically unable to do its job. which is why you have oil analysis.

Why wouldn't you just change the oil in a car at the prescribed interval anyway and save the money that you would spend on the oil sample? for example say the cost of the oil sample is the equivalent cost of 10L of oil and you sample every 10 000 km on the car. so it turns out you only need to change the oil on the bmw every 25 000 km instead of standard 10 000 km .

so over the 25000 km by doing the oil sample in the bmw you pay for 2 oil samples during that 25 000 km period and one oil change. so thats equivalent to 26L of oil (2 x 10L eq cost of the oil sample and a 6L oil change). and the normal case of changing the oil at 10 000 km. so thats an average two and a half oil changes over 25 000 km right? which is the cost of 6L x 2.5 changes = 15L. so for the oil sampling technique you've just bought the equivalent of 11L of extra oil to do the same thing.

As for preventative maintenance, oil sampling also already only really tells you when something has already started to go wrong. and thus is only of use if the integrity of the machine is needed for safety or if the asset where the machinery is heavily relied upon (ie factory machinery where one day of downtime = 1 million in lost turnover). (in other words you can shedule a fix for the problem rather than having it stop completely and be reactive and have no planned alternative.)

So thus you have the truth about using oil analysis to manage oil change intervals in cars. it just doesn't make financial sense. because the engines don't contain enough oil.

[Zeuk in Oz]

My understanding though is that you still need to change filters regularly even if you don't change the oil.

[rob101]

My understanding though is that you still need to change filters regularly even if you don't change the oil.
you are 100% correct.

[BillionPa]

I am currently doing an Auto-RX rinse cycle, and afterwards i will be converting my oil canister to a high flow Amsoil bypass system. Thats the only way i can be sure that the engine is being protected to the maximum capacity available. I do have 6 blackstone kits with TBN here that will be used to determine how many miles I can actually go once the bypass system is in place, and on my old oil, just to see wtf was floating around in there.

I will probably get the pre-oiler too, good way to save the block with lots of short trips.

on a NORMAL car with stock oiling system, an analysis is good once in a while just to see if there is abnormal wear in the engine, and the types of metals detected can help diagnose the problem, but as for "regular" analysis, do it only if you are using extended drain interval testing to see what the max interval is before the oil can no longer protect the engine.

[Gene in NC]

ROB101, thanks for exposing my ignorance on big rigs and your analyis of oil life vs cost of test. Lotta hits on this thread. Hope the takeaway is focus on oil pressure gages.

[BillionPa]

yeah, i cant wait to get the additional gauges installed (oil pressure, oil temp, voltage, fuel pressure, internal air temp, wideband digital A/FR)

those last three will probably be installed later when im not broke!

maybe i should do trans temp and EGT too!!

[rob101]

ROB101, thanks for exposing my ignorance on big rigs and your analyis of oil life vs cost of test. Lotta hits on this thread. Hope the takeaway is focus on oil pressure gages.
lol, i didn't mean to "exposure your ignorance" i just meant to put it in context and explain why it isn't used so much on smaller vehicles. it is a useful tool but its not really that much better than a normal inspection which would work out cheaper. the other thing to point out is that a random oil sample isn't going to tell you much, its more of a constant condition monitoring tool. so in other words if from one service to the next your lead traces increase 4 fold you know there is something starting to go wrong.
its a bit hard to look at one sample in isolation and have it tell you alot.

There is a guy in my company who swears by getting them done before he buys a used car. I think this is probably (if i can be used effectively) the best use for it for smaller vehicles. you can tell has the oil been in as long as they are telling you? how many particulates are in the oil etc. however i have no done this myself, if you want i can post up a typical oil analysis report.