^

simply amazing tho

100,000km without an oil change


WOW! not even the world's best oil can last that long

BMW engines are bulletproof.

i guess so


in that case dont change oil than, waste of money
:thumbsup:

nice thread :hat:

Great thread.

A lot of talk about about oil and oil analysis, but what about the oil filter? Should that be changed the same time as the oil? More or less frequently?

I assume that if the oil analysis comes out good that the filter is still in good condition and doesn't need to be changed until the oil is changed?

The reason I ask is that for my 1992 MR2 Turbo, the manual lists different intervals for the oil and filter:

Severe:

• Oil - 4500kms or 3 months
• Filter - 8000kms or 6 months

Normal:

• Oil - 8000kms or 6 months
• Filter - 16000kms or 12 months

Hard question to answer since the answer differs for different cars, different engine designs, and driving habits.

The job of the filter is to trap insoluables (particles that can't be dissolved into the oil by the detergent additives), the UOA can measure this in %. The measure should be ideally below 0.5%. If the UOA shows above this, good idea is to change it out earlier.

If you're willing to get your hands dirty, you can also cut the oil filter open to examine the filtration media.. any signs of deformation, and you might want to change it a bit earlier.

Perhaps you can stretch the oil to change it the same time as your filter. Again, the only way to really know if you can do that is to do a UOA. Keep in mind the job of the filter is not to 'clean' the oil, or change its color, but rather to trap particles that are large enough to cause damage if circulated. Since it's messy to change the oil and you're already working on the engine, it doesn't take much effort to change the filter as well.

Again the point I'm attempting to make here is that the oil isn't gonna be bad after 5000km's but its cheap insurance to change it by then. I've got clients that take it even further by doing so every 3000km's and they run synthetic. By doing a visual inspection of your oil and filter at those intervals can point out EXTREME wear conditions that can lead to engine failure. That is why I recommend every 5000km's and that is why most mechanics and engine builders I deal with suggest the same.
Now an engine oil analysis will point out many things contributing to regular wear and age but to point extreme wear conditions its not needed.
A most recent example of failure I diagnosed was in a boat. The motor had approx 800 hours of use on it and ran full synthetic. The PO of the boat had changed his oil every 100 hours, in my books thats not often enough for a boat they have slow going motors that carbon foul quick. I suggested 50-75 hours. His boat began to run rough on a recent outing so he called me to come down and find out why. I pulled the valve covers off and found the exhaust valve on cylinder seven wasn't opening all the way and also cylinder number four the intake wasn't opening all the way. His cam was fucked. I asked him when he changed his oil last and inspected it, his response just over 100 hours ago. When I drained the oil and pulled the filter it was full of visible metallic debris. The cam took out his bearings rod and mains. $12000 later his motor was rebuilt and reinstalled in the boat. This would have been avoided if he changed his oil more frequently and before the visible debris suspended in his oil took everything else out. If he changed his oil on the intervals recommended then his repair bill would have been limited to a faulty camshaft replacement. A $50 (his case) oil change could have saved him $10000 the other $2000 would have been for the cam (Its a 40 Grenfell foot boat and no engine repair is cheap on a motor buried below deck).
Is my point clear now? I do have more circumstances like this I've encountered in my 15 years in this business.



I will admit tho on one of my trucks it sees an oil change every few years and unknown mileage I just top up as needed but if she goes its just an excuse to build myself a sweet motor for it

For me, I try to do my oil changes every 30-45days. This oil change coming up I'll be doing a flush because I had to take the valve cover off and reseal it and theres some pretty dirty oil :(.

The point you're making is that you believe in false sense of security.

By the time those EXTREME wear indicators are present, the damage is done and only indicate something needs to be fixed. The UOA can give indicators before it gets to this point.

That's a nice story, yet facts are better than stories.

If this owner has pulled a sample at 50 hrs and had a UOA done, he would've been saved too. Plus he might have caught high metal content before there were visible metal particles in the oil. Then he wouldn't be doing a $2000 repair with fingers crossed nothing else was damaged from the visible metal.

Crystal clear. You support analyzing oil before there is a problem. Why you don't support UOA is still beyond the rest of us.

and very different types of oil filters. Mercedes has 2 types: fleece and paper. The fleece filters will last a long time, while the paper filters might not even make 15K miles before breaking down and getting sucked into the engine.

Jeeze I'm starting to feel ignorant for trying to get through to the ignorant

That wasn't a story it was personal experience.
Aaaaand I'm done.

Lets hope so.

This thread is about dispelling common myths, not pointing out isolated EXTREME cases. UOA is cheap, easy and gives far more info than a visible inspection. Ignorance is not doing a UOA.

For your boat example, the owner might have caught it at 75 hrs if he did an oil change, or might have missed it if visible particles were not evident. The owner might have caught it if he did a UOA at 25, 50, or 75 hrs even if visible particles were not evident.

A lady in the US went 97k miles without a change in her (then) brand new Lexus. There's pics and a story out there somewhere.

im driving a 98 240sx..very laid back driving..usually changing gears at 2500-3000rpms

just the regular daily driving style

I have a couple of questions for you guys, sorry to hi-jack this thread.

I have a 88 tercel with 300,500kms. I bought this car recently and have been changing the oil every 3000kms. Is it necessary? What brand of oil and weight should I use? At the moment I'm using the 5w30 Castrol High Mileage with OEM filter. I do a mix of highway and city driving.

If your car is in good shape (PCV valve working, no coolant leak in the oil, clean air filter), then yes, most modern passenger cars can easily do 8,000-12,000km region, especially with synthetic oil.

I'm not making this up based on 'feelings' or what 'mechanics' have told me, it's based on the UOA's I've browsed on bobistheoilguy.com.

BTW, most 'synthetic' oils aren't really synthetic oils at all, but a highly refined form of conventional oil.

Does the engine not burn oil? Are the seals good? Coolant leak? Functioning PCV valve?

If yes. If it was my car, I would just use any cheapest dino, change every 5,000km / 6months, and call it a day.

Weight is dictated by owner's manual. In 1988, 10w30 was used a lot. Check the manual.

Just my opinion. Do a UOA if you are bored want to know what's in the oil.

Siphon off a few ounces and do a UOA and you'll get better advice than from anyone here.

Instead of hijacking the thread - read it :p ;)

There is a report somewhere that compares all the synthetics and concludes that several of them are no better than conventional oil.

^.

I tend to agree. In day to day driving (unless you have a car like the RDX that requires synthetic due to it's turbo), synthetic oil really isn't needed. Oil companies have been very successful with it's marketing strategies, not to mention Oil engineers have found a cheap way to refine 'synthetic' oils from crude basestocks.

However, one big plus of synthetics is generally longer drain intervals than conventional - they tend to be more shear stable than conventional. (True Group IV and V and 'conventional' Hydrocracked Group III basestocks)

People who change oil more frequently than 8,000km with synthetics are wasting their money IMO. Conventional will perform just as well in such a short interval.

What's a good way to share a PDF file? I have an interesting SAE study performed by Honda Engineers showcasing 0w20 oils vs 5w30.

^ rapidshare?

also: true or false, once you have switched to synthetic oil you cannot go back to conventional, as it has changed the seals in some way.

I'll let Mobil1 answer it for you:



But short answer, totally false. Conventional and Syn Oils are completely mixable and compatible, as long as they are API certified. Just look at all the synthetic blend oils there are, which are a mixture of both.

is mobil 1 a true synthetic now or is it still a blend?

All M1 are blends now, it's not like the good old days. Oil is made of basestocks + additive package (detergents, conditioners, etc).

M1 now contains a mixture of basestocks:

Group III+ (refined conventional)
Group IV PAO, (Poly-alpha-olefins) <- True Synthetic materials.


It's anybody's guess exactly how much, since they don't release formulation information. Difference viscosities will have different blends. People speculate that Oils like their 15w50 is almost exclusively PAO, where as the 5w30 is fairly little.

But most people agree that M1 Extended Performance 5w30 (the Golden Lid that allows 1 year, 24,000km oil changes)
http://ecx.images-amazon.com/images/...500_AA300_.jpg

contains more PAO than the regular 5w30.
http://www.factorydirectoil.com/images/mobil_1_7wur.jpg




ExxonMobil is world's largest producer of PAOs. 5w30 is also their top selling oil, so I wouldn't be surprised if they put as little PAO as they can get away with it in their 5w30. PAO is expensive. There's also evidence that for awhile, M1 5w30 was NOT formulated correctly, and failed the SAE Sequence IV wear test for a long time.