Some years back I worked for a dealer who bought a number of fleet cars that were allegedly maintained well.
These cars (about 3 dozen of them, all about 2 years old) were all Chevrolets, all had between 30 and 35k miles, and as my boss discovered after they were delivered, every single one of them smoked upon startup.
It was discovered that these cars actually did receive oil changes. The distressing part was that they only saw a couple of oil changes each during the entire mileage/time frame the cars were owned by this company.
Every single one of those cars was sludged up beyond belief and the smoking was caused by the fact that the oil that was pumped up to the rocker arm area was not able to drain back down into the crankcase due to the oil return holes being caked solid.
These cars became “filler” jobs in which a mechanic would run out and grab one during a slow spell, etc. It cost my boss quite a bit of money to cover valve cover gaskets, cleaning supplies, oil/filters, and the labor involved to clean out all of this gunk.
I’ve never seen a neglected engine not sludge and there’s no reason to think DD’s Lexus is any different.
(And those 3 dozen cars my boss bought all ran great too; once you got past the oil cloud and errant lifter rattle.)
Drive this car until it dies, don’t trade it in or sell it to someone who doesn’t know or simply doesn’t know any better, otherwise you just may end up in hell.
A comprehensive study in 2006 (SAE 2006-01-3413) concluded the following results on engine wear:
Aged engine oil with 16k miles exhibited similar ring and bore wear rates as new oil
Fully synthetic lubricants have similar ring and bore rates as mineral-based oil
Other research has found the same results, I just don?t have the papers in front of me right now to give the citations.
I would say minimal, if any significant abnormal wear has been done as a result of the 40k miles on the oil. I would change the oil and drive it another 40K. The oil filter will likely not last 40K miles though. So you may want to change that at 20K:)
If You Were Offering Good Advice, Just Think How Revolutionary This Concept Would Become!
The cost savings, petroleum, and energy savings would be huge, nationwide.
Trust me, there’re reasons why people change oil many times more frequently than what you suggest and also reasons manufacturers would void a warranty under your plan.
Why does it sound like you aren’t sure about the filter? Don’t you follow your own advice?
I know. You run your oil for 40,000 mile intervals and filters at 20,000 in your vehicle and get back to us so we can see how it’s working for you.
GM has a 2:1 safety factor. Our new GM car is headed for a 12,000 mile oil change. if 2:1 safety factor, that would be 24,000 miles to oil change. Read the link.
I provided the SAE paper number. What more do you want? I can give you the title as well if you like: ?Effect of Lubricant Properties and Lubricant Degradation on Piston Ring and Cylinder Bore Wear in a Spark-Ignition Engine? The paper was presented at the Powertrain & Fluid Systems Conference & Exhibition, Toronto, Canada, Oct. 2006.
Loafer; there’s more to engine life than piston ring and cylinder bore wear!!! Those are the easy parts. The tough parts are providing enough additives and clean oil to keep the valve gear, timing gears, bearings and other moving parts CLEAN and operating efficiently!
The BMW insides shown in another post on this subject shows what happens when those additives aare depleted and crud builds up.
Any good text on lube oils states that the function of a lube oil is manifold, and includes:
Lubricate surfaces to reduce friction and wear.
Clean the system to keep debris and sludges from forming.
Cool the surfaces sufficiently to avoid heat damage.
Neutralize acids and other undesirable chemicals that form and damage surfaces.
In many cases, act a a noise reducing medium.
Reducing wear on rings and cylinder surfaces is only part of the function of a lube oil, it’s all those other functions that need to be addresssed and cannot be met with 40,0000 miles on the oil and the additives depleted.
I provided the SAE paper number. What more do you want?
Sorry but I don’t (and most here don’t) have access to the SAE library. If you do then please post.
What I want to see is how much sludge there is…does the paper show that??? Was there a controlled study of many engines showing how much longer a engine would or wouldn’t last if not properly maintained??
For Sale: 2006 Lexus IS 250
Low Miles - 40,000 Miles
Body Is In Excellent Condition
Well Maintained, Oil And Filter Changed
Every 40,000 Miles.
For Sale: 2006 Lexus IS 250
Low Miles - 40,000 Miles
Body Is In Excellent Condition
Well Maintained, Oil Changed Every
40,000 Miles, Filter Every 20,000.
For Sale: 2006 Lexus IS 250
Low Miles - 40,000 Miles
Body Is In Excellent Condition
Well Maintained, Oil And Filter
Changed Every 16,000 Miles.
For Sale: 2006 Lexus IS 250
Low Miles - 40,000 Miles
Body Is In Excellent Condition
Well Maintained, Oil And Filter
Changed Every 5,000 Miles.
Do the longer oil change intervals make you skeptical about the maintenance of the whole vehicle? All things except oil change intervals being equal, which one would you choose?
That’s IF AND ONLY IF…the Seller states that the oil and filter was changed every 40k miles. The couple of people I know who abuse their cars this much…would NEVER tell the suspected buyer…Their attitude is…“It’s THEIR problem…NOT MINE.”
All SAE papers are copyright protected and available to the public: $15 non-members, $12 members.
Extended oil change intervals are possible on modern EFI engines without significant oil degradation or sludge formation by maintaining optimal engine oil temperature (too high and too low can be problematic) and by proper ventilation of the valve train through the PCV system.
Some engines are problematic in the sludge department. I believe Toyota has already fixed their problem, and I?m sure others have as well.
Is 40K interval too high? Possibly. Do I think any significant damage resulted to the OP’s engine ? No.