His all just a quick question about using a thicker oil in a vehicle that doesn't "require" it. For example if a car or truck calls for a 5w-20 and you put 15w-40 in it, will that cause wear on the oil pump trying to pump that oil instead of a 5 20? Not just the oil pump but are there other parts that are or could be strained?
High viscosity oil
- Thread starter haskell454
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Nope,won`t hurt a thing. May feel a lil sluggish,that`s all.
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That's what I figured but wasnt sure about it thanks
If you are in a place and climate where it is warm (such as Palm Springs in the summer) you can get away with it easier. I sometimes buy the heavy oils if they are on sale.
Your question will most likely receive a lot of "opinions". There are very good reasons the engineers of your vehicle recommend a certain viscosity oil. If you haven't read the Motor Oil University BITOG Motor Oil University please click onto the link and do so. The author has a very good explanation of this very subject. I have wrenched on more different types of engines (including jet) than I care to remember, and have always found that it's best to stay with the manufacturer's recommendations and not try to "second guess" them. Unless the engine is very worn, stick to the correct viscosity for maximum engine longivity. I've ran a lot of them past 200,000 by doing just that, and not a single one has ever failed me......
Unless the oil was "chosen" for reasons other than providing maximum engine life, banking on the original owner not feeling slighted by an engine that they onsold, had the car rust out, or wrecked in the vast majority of applications.
BTW, the link has a lot of inaccuracies.
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BTW, the link has a lot of inaccuracies.
dnewton3
Staff member
I would caution against making such a wide grade shift.
Going from 5w-20 to 5w-30 isn't bad. But a 40 grade might have implications past what you will see initially.
Much of it depends upon what the vehicle was designed to run on. Modern engines designed in the last several years are spec'd for 20 grade. A much thicker oil may not flow well into all the necessary places, or perform as needed in hydraulic plungers like cam phasers and chain tensioners, etc.
Just stick with what the OEM specs; best advice. You're not going to "out think" the OEM engineering and reliability testing.
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Originally Posted By: dnewton3
I would caution against making such a wide grade shift.
Going from 5w-20 to 5w-30 isn't bad. But a 40 grade might have implications past what you will see initially.
Much of it depends upon what the vehicle was designed to run on. Modern engines designed in the last several years are spec'd for 20 grade. A much thicker oil may not flow well into all the necessary places, or perform as needed in hydraulic plungers like cam phasers and chain tensioners, etc.
Just stick with what the OEM specs; best advice. You're not going to "out think" the OEM engineering and reliability testing.
We have a winner!
Rather than protecting better, a thick oil may actually result in more wear than a thin one. Several studies have shown that lower viscosity oils actually perform better as measured by bearing and ring wear.
Originally Posted By: jetmech1
I do know that bearing clearances today are extraordinarily tight compared to the engines of "years gone by" and do require a "thinner" viscosity to provide the flow necessary for proper cushion and cooling.
dnewton3
Staff member
As the old addage goes:
As thin as possible; as thick as necessary.
Thin equals better flow at start up, good compatibility with cam phasers, chain tensioners, etc.
Thick equals better cushion in bearing journals, COB interface, etc.
Therefore, lubricants (like most every single thing in life) is a compromise.
Again, are you in a postion to out-think the engineering team, and the hundreds of hours of reliability testing, etc?
A small grade shift likely will not result in any discernable difference. But a big grade shift will have some implications (pro and con) down the road.
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Originally Posted By: Zaedock
Originally Posted By: jetmech1
I do know that bearing clearances today are extraordinarily tight compared to the engines of "years gone by" and do require a "thinner" viscosity to provide the flow necessary for proper cushion and cooling.
Originally Posted By: Zaedock
Originally Posted By: jetmech1
I do know that bearing clearances today are extraordinarily tight compared to the engines of "years gone by" and do require a "thinner" viscosity to provide the flow necessary for proper cushion and cooling.
That's a lot of cool accurate info, but doesn't really have anything to do with the implications of running a 15W40 in a late model in lieu of 5W20 and whether or not the bearings were "designed" for it.
Just to comment on your info though, my 1959 Willys was spec'd for 20W oil as well.
Originally Posted By: Zaedock
That's a lot of cool accurate info, but doesn't really have anything to do with the implications of running a 15W40 in a late model in lieu of 5W20 and whether or not the bearings were "designed" for it.
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