This guy claims a heavier oil will cause more wear

[SR5]

Originally Posted by ZeeOSix
^^^
"To be honest I can't see any modern car grind to a halt or bind up on something like M1 0W-40. It may even stay a bit tighter over the long run."


Yeah, tighter over the long run due to less wear because of better MOFT and HTHS viscosity.

Exactly!

 

[RDY4WAR]

You also have to consider heat generation. Heat can cause excessive bearing wear through expansion of the softer bearing material, closing up the clearance. The engines that spec the 15w-50 for racing use also have larger journals for more oil volume in the bearings at the same clearance with less eccentricity and large oil capacities with coolers (8 quarts + OEM cooler (2015 and up) for the Coyote 5.0L) to help dissipate that heat.

 

[aquariuscsm]

This begs me to ask the question. What effect would using 20W50 in an engine specd for 0W20 have on the life of the engine? I'm sure it would run like a total dog, but damage wise, any negative effects?

 

[kschachn]

Originally Posted by RDY4WAR
You also have to consider heat generation. Heat can cause excessive bearing wear through expansion of the softer bearing material, closing up the clearance. The engines that spec the 15w-50 for racing use also have larger journals for more oil volume in the bearings at the same clearance with less eccentricity and large oil capacities with coolers (8 quarts + OEM cooler (2015 and up) for the Coyote 5.0L) to help dissipate that heat.

So engines operated in areas where high viscosity oils are recommended (such as the Middle East, Australia, etc.) wear out faster due to the oil?

 

[SR5]

Originally Posted by aquariuscsm
This begs me to ask the question. What effect would using 20W50 in an engine specd for 0W20 have on the life of the engine? I'm sure it would run like a total dog, but damage wise, any negative effects?


The most recent Toyota Camry in Australia with the 2.5 Litre 2AR-FE VVT-I engine can use: 0W20, 5W30, 10W30 and 15W40.

As Shannon says, the bearings just take what they need.

Oil isn't going to push the metal out of shape and cause damage. All that will happen is that on a thick oil the engine will rev out a bit slower, be a bit more sluggish and use a touch more fuel.

Change the oil and you are back to normal. Don't forget the viscosity difference between a cold (below freezing) oil and a hot (engine at full operation temp) oil, is far greater than the difference between the hot oil viscosity of 0W20 and 20W50. You effectively run a very thick oil every time you start your car in winter, as long as you can pump it and crank it, you should be OK.

 

[Bryanccfshr]

I have a question. Are there 15w40 PCMOs marketed in Australia or is the latest spec- SN all that is needed and it's a all fleet?

Originally Posted by SR5
Originally Posted by aquariuscsm
This begs me to ask the question. What effect would using 20W50 in an engine specd for 0W20 have on the life of the engine? I'm sure it would run like a total dog, but damage wise, any negative effects?


The most recent Toyota Camry in Australia with the 2.5 Litre 2AR-FE VVT-I engine can use: 0W20, 5W30, 10W30 and 15W40.

As Shannon says, the bearings just take what they need.

Oil isn't going to push the metal out of shape and cause damage. All that will happen is that on a thick oil the engine will rev out a bit slower, be a bit more sluggish and use a touch more fuel.

Change the oil and you are back to normal. Don't forget the viscosity difference between a cold (below freezing) oil and a hot (engine at full operation temp) oil, is far greater than the difference between the hot oil viscosity of 0W20 and 20W50. You effectively run a very thick oil every time you start your car in winter, as long as you can pump it and crank it, you should be OK.

 

[SR5]

Originally Posted by Bryanccfshr
I have a question. Are there 15w40 PCMOs marketed in Australia or is the latest spec- SN all that is needed and it's a all fleet?


All the majors make a 15W40 PCMO that is usually rated API SN and ACEA A3/B3. Eg Castrol GTX 15W40 "Modern Engine". A mineral oil.

These have recently been upgraded to semi-synthetics so now we have GTX 15W40 "UltraClean". Similarly we have a semi-synthetic Valvoline EngineArmour 15W40 that is SN & A3/B3.

I expect at some stage these will all be upgraded to SN-Plus, but I don't think that has happened yet.

These 15W40 PCMO's are some of the best value oils in Australia and heavily used by a large group of people. We use to be a 20W50 nation, but now we are more of a 15W40 nation.

For beaters you can get cheaper API SL 15W40 mineral oils, or for a bit better you can get 10W40 semi-synthetics that carry the higher ACEA A3/B4 spec and maybe a few OEM like VW 502. Plus we get all the normal full synthetics. All PCMO oils.

Check out this BITOG link to typical Oz oils

 

[DGXR]

There is definitely a reduction in pumpability with higher viscosity oils, depending on ambient temperatures. I think that's what the video guy is saying.

Higher viscosity does not equal better oil film strength or better wear protection.
Higher viscosity *can* reduce oil consumption due to slower seepage past rings/seals.

 

[kschachn]

Originally Posted by DGXR
There is definitely a reduction in pumpability with higher viscosity oils, depending on ambient temperatures. I think that's what the video guy is saying.

Higher viscosity does not equal better oil film strength or better wear protection.
Higher viscosity *can* reduce oil consumption due to slower seepage past rings/seals.

I'm not sure what you're saying here, there is no reduction in pumpability unless the oil is so thick it will not flow to the pump pickup. Once it flows to the pump then it will be pumped. It will take more energy to do so but there is no reduction in pumpability.

And MOFT not related to viscosity? Where do you see that? Regardless of the bearing clearance the MOFT is always higher with increasing viscosity.

There really is no instance where heavier oils cause more wear unless it is the catastrophic situation where the oil is so thick it cannot be pumped. The easiest way for that to happen is in (very) cold weather where an oil has an improper winter rating for the conditions.

 

[RDY4WAR]

Originally Posted by DGXR
There is definitely a reduction in pumpability with higher viscosity oils, depending on ambient temperatures. I think that's what the video guy is saying.

Higher viscosity does not equal better oil film strength or better wear protection.
Higher viscosity *can* reduce oil consumption due to slower seepage past rings/seals.


Pumpability will remain constant, but flow will be reduced, thus the increase in oil pressure with higher viscosity.

I haven't seen an oil increase with ambient temperature increase. On all of my vehicles, they stay in the same 210-230°F range regardless if it's 20°F in January or 100°F in July. The only difference has been how long it's taken to get up to that temperature. The temps only exceeded 230°F when I used a higher viscosity oil (increased drag, friction, pressure, and aeration = more heat).

I've actually seen oil consumption increase with higher viscosity because the thicker oil film increased the transport past the rings.