Engines don’t reject oil, nor do they accept oil gracefully. There is no special consideration for Ford, GM or Toyota engines when it comes to changing oil, nor is Saudi Arabia a meaningful case that can be extrapolated to the rest of the world. Your last sentence is difficult to parse.
Up oil weight with high mile engines?
- Thread starter george1122
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dnewton3
Staff member
There are two ways to view this...
- treating the symptoms
- treating the root cause
The reason folks will often "up the vis" in older engines is because they are often the victim of mileage induced problems like poor valve stem sealing and/or less-than-ideal piston ring sealing. Both these can result in some additional oil burning.
So typically owners will often step up a grade (or two) to combat the oil loss. Upping the vis is, essentially, a stop-gap measure that does not address the root cause. It doesn't fix anything; it only masks the problem which is likely to continue to degrade. As to when engines are treated to the traditional "up the vis ante" action, well, that depends on a slew of things which no singular answer can satiate.
Conversely, using a lube with a very stout cleaning additive package can address at least one, if not both, of those conditions. The rings can be liberated by oil when high-detergent lubes are used. And the valve stem seals can also be improved if they are not actually worn, but only restricted from fully sealing by varnish, etc. (NOTE: if the stem seals are truly worn, no oil can fix that). Essentially, restoring the engine to a better functioning state is a superior way to address the concern.
Lubes which I believe can achieve this would be HPL, VRP, and some Amsoil products.
- treating the symptoms
- treating the root cause
The reason folks will often "up the vis" in older engines is because they are often the victim of mileage induced problems like poor valve stem sealing and/or less-than-ideal piston ring sealing. Both these can result in some additional oil burning.
So typically owners will often step up a grade (or two) to combat the oil loss. Upping the vis is, essentially, a stop-gap measure that does not address the root cause. It doesn't fix anything; it only masks the problem which is likely to continue to degrade. As to when engines are treated to the traditional "up the vis ante" action, well, that depends on a slew of things which no singular answer can satiate.
Conversely, using a lube with a very stout cleaning additive package can address at least one, if not both, of those conditions. The rings can be liberated by oil when high-detergent lubes are used. And the valve stem seals can also be improved if they are not actually worn, but only restricted from fully sealing by varnish, etc. (NOTE: if the stem seals are truly worn, no oil can fix that). Essentially, restoring the engine to a better functioning state is a superior way to address the concern.
Lubes which I believe can achieve this would be HPL, VRP, and some Amsoil products.
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Most people want to believe that the mfgr of your vehicle knows what they're doing when it comes to engine building. But that's not always the case. I've posted on here several times about my '11 chevy equinox, being a oil consumer from day one. It used a qt of oil every 750 miles. The owner's manual says not to use 40 wt oil, but I've found that to be a better choice. It uses less oil between changes. Not 100% better, but double what I got with 5w30. The engine sounds much quieter with no noises of any kind. I've heard people say that using some type of 40 wt oil will also help keep the timing chain from wearing out, better than 5w30 will. Besides high oil consumption, timing chains are a common thing you need to throw money at if you own a 2.4 chevy engine. But unless your having consumption issues, keep using whatever oil that's been doing it's job. Don't fix it if it ain't broke.,,,
Why not go thicker and cleaner with VRP 10W40.
This will be my new "high mileage" oil, in the big 6L jug
This will be my new "high mileage" oil, in the big 6L jug
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Engines with high mileage do not need thicker oil. If your engine has been running 0w20 for 200k+ miles, and it runs just like the day you bought it, you can continue to use 0w20 till the vehicle is no longer drivable.
The reason is, even if an engine has 300k+ miles, the bearing clearances do not increase at all. Bearings are supposed to never touch, and if they do touch even for a split second, what you end up with is a spun bearing, not just a “little wear” that you can walk away from.
Bearings wear from contaminants in the oil, but even then the bearing might have some scoring, but the overall clearance does not get any bigger, not even one bit. You always see engines that were taken care of by regular oil changes that have 300k+ miles that have bearings that look just like brand new, and measure as brand new. This is because bearings do not wear!
The main reason someone might use thicker oil in a high mileage engine is because like some people already said the valve stem sealing can be an issue, and piston ring sealing could be an issue. The latter will almost never happen if oil changes have been done regularly and quality oil was used.
The biggest misconception is “high mileage engines have increased bearing clearances”. They do not if they are healthy.
The reason is, even if an engine has 300k+ miles, the bearing clearances do not increase at all. Bearings are supposed to never touch, and if they do touch even for a split second, what you end up with is a spun bearing, not just a “little wear” that you can walk away from.
Bearings wear from contaminants in the oil, but even then the bearing might have some scoring, but the overall clearance does not get any bigger, not even one bit. You always see engines that were taken care of by regular oil changes that have 300k+ miles that have bearings that look just like brand new, and measure as brand new. This is because bearings do not wear!
The main reason someone might use thicker oil in a high mileage engine is because like some people already said the valve stem sealing can be an issue, and piston ring sealing could be an issue. The latter will almost never happen if oil changes have been done regularly and quality oil was used.
The biggest misconception is “high mileage engines have increased bearing clearances”. They do not if they are healthy.
While I've stepped up in viscosity in high mile engines, it is often for reasons such as Ford's notorious leaking oil pump back plate and leaking chain tensioners on the 5.4L. Such leaks starve the cylinder head for oil and a low viscosity oil is a sure-fire way to have an engine failure.
However, we would do well to remember that chains last longest with a true 30 viscosity oil. Timing chains, balancer chains, oil pump drive chains (yes, they exist) and so on. When we move too far down from that viscosity, wear increased so much that special chain link pin coatings needed to be developed to ensure adequate life. These coatings also have a finite life and once breached, the components wear rate increases fast. The good news is that for most people, engine life is adequate.
Whether your vehicle choice has an engine with all components designed for ultra low viscosity oils or not, remains to be seen. Toyota is a solid bet. H/K, not a chance, as this is exactly where H/K cuts corners.
Here in South Florida, I never use anything less than a quality, synthetic 5W-30.
Take a look at the wear on the DLC (diamond like coating). This is an engine that spec's 0W-20, and has been configured to hold up well with that viscosity, through the use of very specialized coatings. However, what happens is that once the coatings wear off, the engine is trash. The use of significantly higher viscosity such as a robust 5W-40, prevents such wear. Period, end of story.
However, we would do well to remember that chains last longest with a true 30 viscosity oil. Timing chains, balancer chains, oil pump drive chains (yes, they exist) and so on. When we move too far down from that viscosity, wear increased so much that special chain link pin coatings needed to be developed to ensure adequate life. These coatings also have a finite life and once breached, the components wear rate increases fast. The good news is that for most people, engine life is adequate.
Whether your vehicle choice has an engine with all components designed for ultra low viscosity oils or not, remains to be seen. Toyota is a solid bet. H/K, not a chance, as this is exactly where H/K cuts corners.
Here in South Florida, I never use anything less than a quality, synthetic 5W-30.
Take a look at the wear on the DLC (diamond like coating). This is an engine that spec's 0W-20, and has been configured to hold up well with that viscosity, through the use of very specialized coatings. However, what happens is that once the coatings wear off, the engine is trash. The use of significantly higher viscosity such as a robust 5W-40, prevents such wear. Period, end of story.
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"If", is a relative term. If you bring your engine someplace that knows what they're doing rebuilding it, they will check bearing clearances and ring clearances. Why do you think they do that if those clearances never change?. A vehicle with 2-300,000 miles will have some wear on the internals. Even if they were never ran with low, or old oil in them. They are not designed to last forever. If you bought a used car, you really don't' know if the oil was maintained to the letter of the law. And even with a new car, changing oil can be forgotten about, or put off to a more convenient time. If the car has been overheated and the oil hadn't been changed, that's like running old used up oil in it. That's why things get measured when getting rebuilt. Just throwing the old parts back in without measuring them, is just reassembly.,,
And on the other hand, besides a small increase in fuel consumption there's no real downside to using a higher grade. It always helps to reduce wear and it provides a cushion to help mitigate fuel dilution.
I respectfully disagree. I have personally opened up a few engines and have seen significant bearing wear. I had a 454 that a friend and I disassembled, with the babbit worn off on the lower shells to the copper. It was a running engine, but I don't know the history other than the truck that it was in pulled a race car all over the northeast. I ran that engine a year before we torn it down. Witnessed a few small blocks with similar but less extreme wear to the rod and main bearings. Of course this was a different time as well. Oil quality was abysmal, engines had small sumps even for large displacement, and 100k miles was worn out.
I have also witnessed a few larger diesel engines (Mack 300, IH 466) that had worn bearings. Replaced when rebuilt. But these engines are designed to be rebuilt and returned to service relatively quickly.
Now the argument that a thicker oil could have prevented or prolonged the wear, I doubt it. Engines wear. I do think that in all cases, more fastidious maintenance may have extended the engine's life, but would not have prevented the end result.
My daily work commute 2006 Ford Focus 2.0l is about to hit 298k on the way home tonight. it has had Mobil 1 extended life 0w20 since about 98k when I got it. I was thinking about going to a 5w30 but why? It is at the full mark when I change the oil at around 10k intervals.
Back in the day, when bearings could be expected to wear out in 100k miles, it made sense to compensate for the increased clearance and lower oil pressure with a thicker oil.
These days, if a healthy engine is torn down at 300k miles, the bearings are often still in great shape, and the clearances are still within the factory spec for a new engine.
If you suspect a lot of bearing wear (lower oil pressure, bearing material in oil), then a thicker oil might help delay the inevitable. Otherwise, it shouldn't be necessary.
These days, if a healthy engine is torn down at 300k miles, the bearings are often still in great shape, and the clearances are still within the factory spec for a new engine.
If you suspect a lot of bearing wear (lower oil pressure, bearing material in oil), then a thicker oil might help delay the inevitable. Otherwise, it shouldn't be necessary.
Yes there is always wear regardless of what oil is being used. No oil and no grade produces zero wear. However, the physics of film thickness shows that the better the parts are kept separate the lower the wear. It’s not linear though, and whether it matters to you at what level is up to you.
dnewton3
Staff member
Interesting. I don't believe that grade is available in the USA. Is that an Aussie thing?
https://www.valvolineglobal.com/en/restore-protect/
Yes, I wish we got a 40 grade over here even if it's a pcmo 40 but I'd prefer a euro 40.
I think in the US you are always good to go up a grade, to just match what the same engine uses in the ROW. It might cause you to use 1% more fuel, but if it saves a cam from scoring or prevents a timing chain problem, then its certainly worth it.
I have seen UOA of Corvettes driven on track, and if they go with oil that is too thick, titanium ppm jumps up. If memory serves me correct, they were for C6 z06
Or you have a Volvo with a plugged pcv system. Those things puke oil like crazy once plugged.If you engine "rejected" oil, its already too late.
OK. I have a daily driver. 13' CRV AWD EXL. Bought it new. I maintained it from day one. Takes 0W20 oil as per manual and oil cap. Currently has 614,877 miles on it. The rings coked once. EPR 109 took care of that in 3 oil changes. The only thing I do different now is add BG PN 115 at every OCI. Hasn't burned oil in over 300,000 miles since the EPR 109 thing. That being said, I'm sticking to whatever the oil cap tells me to use. Just plain ole synthetic 0W20...nothing special. Whatever I catch on sale. Filters are whatever is on sale too. Runs like a champ ! Unfortunately, I just NOW how to install new CATS in it. I think I got my $$$$$ worth out of those CATS. K24 engine.
This why I won't use very thin oils. When I drove my new car home the very first thing I did was to drain the thin stuff out and replaced it with a 5W-30 oil . Posters such as you have taught me what I need to know about such matters and I appreciate it so much.
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