Motor oil viscosity

Been watching oil gurus on Youtube, they say the only reason to run 0/20 motor oil is the EPA is requiring higher fuel economy, and GM has just recently went from 0/20 to 0/40. Because of all the engine failures. Does anyone run a heavier oil than 0/20? I have a bunch of 5/30 on the shelf, could easily use that, but stocked up big on 0/20.

 

I have used Amsoil 0W30 in my 2007 Tacoma V6 since from the 1st change at 5K. It now has 265,000 miles with no failures and no leaks. I would not be afraid to use 0W20.

 

There is the problem.
Stop watching YouTube.

Watch the owners manual.

That's seriously the best advice.

 

The reality with oil is that most oils are "good enough" for most usage in most engines. Where it starts to matter is at the margins. If you overheat, you don't want a 20 grade turning into a 10 grade or less, especially if you are working the engine hard at that time for whatever reason. If you have an issue of wear somewhere and the lower viscosity grade oil isn't enough to keep the parts separated, it can turn into trouble and create wear. That is ultimately why the GM recall is what it is - the 0W-40 is used to provide more margin against potential failures in an engine that is known to be problematic in certain areas.

I tend to take the stance that the best oil to run is the thickest option that will still work in your coldest climate throughout the year.

The manual is not really the best advice at all, as it is driven by political and economical motives, and not by what is best for the consumer. I would wholeheartedly say to follow the manual if it still provided a temperature chart indicating allowable different viscosities based on what the lowest temp experienced will be. They don't do that anymore, so I tend to make the decision on my own rather than listen to the CAFE-driven suggestion.

There is nothing wrong with YouTube if the videos are based in fact. Not all of them are, but a lot are.

You can absolutely run 5W-30 safely if you wanted to, but I'm not going to tell you what to run. I would personally choose 5W-30 over 0W-20 in any climate though.

 

Erl

 

The owners manuals in most vehicles usually give a range of oil weights that are acceptable, not just one. It's often based on the operating temperature where you live. Often the number on the oil filler cap is different than what is in the owners manual.

It's not unusual for vehicles to run better on a slightly thicker oil. Especially higher mileage vehicles. I've seen old trucks oil pressure improve and oil consumption stopped or reduced just by moving to one grade thicker oil.

I buy oil for 3 vehicles and several pieces of lawn equipment, generators etc., and just use 5-30 in all of them.

 

Gm might be using 0w-40 to try and mitigate the failure but that doesn't necessarily mean the original 0w-20 was the cause of the failure

 

I have an 05 that calls for 5W-30. Some years later, they dropped the oil viscosity to something like 0W-20. Yup, I am sure the engine was completely redesigned to reflect the change. Or could it be the EPA was redesigned to make the change?

0W-20 will pull most engines through the warranty period, but it sure do help fuel efficiency.

 

My 2nd gen states "5W-30" on the oil cap. I tried using other viscosities to see what would happen. I found the Toyota engineers to be correct (imagine that!) and went back to 5W-30. It seemed to me to run the best. I have 181k miles and the engine runs better than brand new. Can't argue with that!

 

You could mix the 0W-20 and 5W-30 you already have. Wouldn't hurt. You could also get some 5W40 to mix with the 0W-20 to come up with something very close to 5W-30. If it was me, I'd mix what you have and use it up. Oil does have a shelf life.

 

I like Lake Speed, Jr.'s YouTube videos on oil tech. He's a serious tribologist, not some random goober.

 

I'm not sure how the 4cyl works, but the VVT-i in the 4.0 V6 relies on oil pressure to work. Wouldn't messing with oil viscosity cause issues with the engine timing in that case?

 

The 4 cylinder also has VVT, that is how they make such good gas mileage. This pickup makes about 5 mpg better than the old 91 it replaced, and has a larger engine.

 

All my vehicles state 5w30 is the preferred oil

So that’s what I do

Keeps it simple too

 

No. Your oil viscosity already ranges across very large differences in thicknesses from cold to hot. Changing the overall viscosity just shifts that curve a bit. The VVT only needs pressurized oil, it doesn’t need a specific pressure.

 

In the old, old days, I used to buy motor oil by the case at Costco and buy six oil filters at a time when they're on sale.

These days, ordering from Amazon is so efficient and reliable, I don't keep anything at all on the shelf and literally order my oil and one filter the week before a scheduled oil change.

That's called just-in-time inventory.