Up oil weight with high mile engines?

[george1122]

There are various weights of oil, of course. Is there an amount of miles on a vehicle where it is a good idea to jump up a weight in oil?

In other words, is there a certain amount of miles where to get the same function from the weight a person was using, that person needs to go up in weight?

Hypothetical example: The manual says 5W20 or 5W30 should be used. After 150K miles, does a person need to jump up to 5W40 to get the same effect that the previous oil provided when the car was newer?

 

[ripcord]

No, there is no rule of thumb for when (or if) to increase the weight of the oil based on mileage. There are too many factors involved.

The main reasons to increase the oil weight are to compensate for a design or materials flaw in a particular engine family, to attempt to reduce oil burning, or to compensate for worn bearings and low oil pressure.

Generally, there is no risk with increasing the oil weight by a grade (or even two), such as going from a 20 weight oil to a 30.

 

[Rygrego]

No, there is no rule of thumb for when (or if) to increase the weight of the oil based on mileage. There are too many factors involved.

The main reasons to increase the oil weight are to compensate for a design or materials flaw in a particular engine family, to attempt to reduce oil burning, or to compensate for worn bearings and low oil pressure.

Generally, there is no risk with increasing the oil weight by a grade (or even two), such as going from a 20 weight oil to a 30.

Or 40 like GM did with the 6.2 engines a couple of months ago. I personally have never continued with a 0W20 past the first oil change on any of my vehicles. My 2017 Hondas run 5W30 , my Jeep runs 15W40 and my 16 Yukon runs 15W40. no issues at all. The 0W20 and lower are nothing but a CAFE standard and do not contribute to engine longevity.

 

[spasm3]

I up the viscosity in New and low mileage engines!

 

[RDY4WAR]

...Is there an amount of miles on a vehicle where it is a good idea to jump up a weight in oil?

No. There's 3 factors that determine the ideal oil viscosity/grade.

1. Operating oil temperature
2. Rod and main bearing clearance
3. The load on those bearings

None of those variables are changing with high mileage. If you do wear the bearings enough that the clearance warrants a jump in viscosity, something's wrong.

That's not to say you can't use a grade higher viscosity. It's just that most engines will see no benefit.

 

[Jetronic]

There are various weights of oil, of course. Is there an amount of miles on a vehicle where it is a good idea to jump up a weight in oil?

In other words, is there a certain amount of miles where to get the same function from the weight a person was using, that person needs to go up in weight?

Hypothetical example: The manual says 5W20 or 5W30 should be used. After 150K miles, does a person need to jump up to 5W40 to get the same effect that the previous oil provided when the car was newer?

1 mile. the sooner you start, the sooner and more you benefit. Why wait till the damage is done?

 

[Navi]

Im using 5w-40 from when the vehicle was new. After 3000 miles with.the factory 5w-30 oil that gets drained and in goes the 5w-40.

As for thin oils like 0w-20/0w-16/5w-20 etc...dont use it. Go thicker unless the engine rejects it such as running rough or a check engine light comes on.

Of course you should use what the climate/environment calls for like in Saudi Arabia they simply use the thickest motor oil readily available. In extreme cold the 0w oils rule the scene. For myself 5w-40 is just fine for my needs.

 

[ripcord]

No. There's 3 factors that determine the ideal oil viscosity/grade.

1. Operating oil temperature
2. Rod and main bearing clearance
3. The load on those bearings

None of those variables are changing with high mileage. If you do wear the bearings enough that the clearance warrants a jump in viscosity, something's wrong.

That's not to say you can't use a grade higher viscosity. It's just that most engines will see no benefit.

1 mile. the sooner you start, the sooner and more you benefit. Why wait till the damage is done?

Witness the two schools of thought on the site. The eternal argument between the thicky's and the thinny's.

 

[george1122]

1 mile. the sooner you start, the sooner and more you benefit.

Im using 5w-40 from when the vehicle was new. After 3000 miles with.the factory 5w-30 oil that gets drained and in goes the 5w-40.

As for thin oils like 0w-20/0w-16/5w-20 etc...dont use it. Go thicker unless the engine rejects it such as running rough or a check engine light comes on.

Of course you should use what the climate/environment calls for like in Saudi Arabia they simply use the thickest motor oil readily available. In extreme cold the 0w oils rule the scene. For myself 5w-40 is just fine for my needs.

How does a person know whether the engine rejects it or not?

 

[Jetronic]

Witness the two schools of thought on the site. The eternal argument between the thicky's and the thinny's.

My issue is, on a new car you don't know what the actual bearing clearance is, and the load on the bearings varies constantly. Maybe you know the operating oil temperature, maybe not. and the operating temperature can go up plenty if you go over a mountain range, just because cooling is less up there.

 

[Navi]

I noticed the owners manuals of many cars will state a different viscosity depending on the geography.

For Toyotas it will state one viscosity for North America which is usually 0w-20. In Europe Toyota will state that 5w-30 is acceptable. In extremely hot climates Toyota will go as far as 15w-40. So whether it be 0w-20 or 15w-40 it will work in their engines.

GM made the jump from 0w-20 to 0w-40. So in most if not all engines you can go thicker without worry.

 

[Jetronic]

How does a person know whether the engine rejects it or not?

Never seen that happen.

 

[Navi]

How does a person know whether the engine rejects it or not?

I cant state that all engines will accept thicker oil gracefully because I simply dont know that to be true. I can say that Ford, GM and Toyota engines will accept it. All those cars being sold and operated in Saudi Arabia will accept it.

Thus I put the "rejection" caveat out there in the event there is a special case scenario.

 

[george1122]

I cant state that all engines will accept thicker oil gracefully because I simply dont know that to be true. I can say that Ford, GM and Toyota engines will accept it. All those cars being sold and operated in Saudi Arabia will accept it.

Thus I put the "rejection" caveat out there in the event there is a special case scenario.

I wonder how much of a difference it makes where a specific model car is made. Some models are made in a number of countries. I don't know whether the spaces between the parts are the same or not.

 

[RDY4WAR]

My issue is, on a new car you don't know what the actual bearing clearance is, and the load on the bearings varies constantly. Maybe you know the operating oil temperature, maybe not. and the operating temperature can go up plenty if you go over a mountain range, just because cooling is less up there.

Those parameters are how OEM engineers decide the appropriate grade. It's based on HTHS but presented as a grade since it's more publicly familiar. The worst case scenario is factored in that decision.

Also note that I said most engines would see no benefit, not all. As with anything else in life, there are exceptions to the rule.

If you're really concerned about high mileage, look for a better quality oil, not a higher viscosity one.

 

[SR5]

In Australia they don't sell many "high mileage" oils, it's just not a thing here.
Rather most people step it up a viscosity grade as the car ages.

Stuff like Castrol Magnatec 10W40 or Valvoline DuraBlend 10W40, both semi-synthetic and both are API SP and Euro A3/B4 rated. Very affordable oils here. If you prefer a full synthetic we also have Magnatec 5W40 or SynPower 5W40 or Penrite 5W40 or Shell 5W40 etc.

The general rule of thumb is to step it up a grade when you start noticing oil consumption.

 

[cptbarkey]

If you engine "rejected" oil, its already too late.

 

[SR5]

Not that we stop at 40 grades ....

 

[Patman]

Oil viscosity is not a “weight”. That’s something that is misunderstood by many people, including on here. They are grades.
So the proper term would be to say 30 grade, not 30 weight.

 

[kschachn]

I wonder how much of a difference it makes where a specific model car is made. Some models are made in a number of countries. I don't know whether the spaces between the parts are the same or not.

This is a common concern that isn't true, along with the "electric oil pump" that magically allows higher viscosity oils once you drive to Mexico.

Engines can be designed to tolerate low viscosity oils without damage but that doesn't preclude the use of ones with a higher HT/HS. Oil molecules aren't that big, they will fit in the space.