Toyota’s stance on using a heavier weight oil

[thastinger]

I discovered that MMO worked remarkable well as a power steering fluid in my '98 K1500. I had leaky lines and the reservoir ran dry one time. I didn't have any power steering fluid on hand but had a couple bottles of MMO on the shelf collecting dust so in it went. Ran that for awhile before finally sucking it all out and replacing it with Valvoline MaxLife power steering fluid. Between the two of those, no more leaks since. So win?

The stuff is fantastic, not well respected here but the same people who poor mouth MMO for not having ingredients that show up on a VOA are the champions of Valvoline Restore and Protect...which also shows nothing special on a VOA.

 

[kschachn]

The stuff is fantastic, not well respected here but the same people who poor mouth MMO for not having ingredients that show up on a VOA are the champions of Valvoline Restore and Protect...which also shows nothing special on a VOA.

Actually it is the stuff that does show up on an SDS which is telling. That VOA wouldn't show anything.

 

[ZeeOSix]

“Tighter engine tolerances require thinner oil”. If this was true, how is it possible that Australian owner manual has oils 0w-16, 0w-20, and 5w-30 for the same engine? Where is the logic?

If people say anything about the connection between journal bearing clearance and the impact of oil viscosity on the MOFT, it should be more along the lines of: "Larger bearing clearances need thicker oil to maintain film thickness".

Tight bearings will still produce more MOFT as the oil viscosity increases, but as the clearance increases, it's harder for the bearing to maintain MOFT and will actually start loosing film thickness unless thicker oil is used. This is why many engines can specify a whole range of viscosity like xW-20 to xW-50 if CAFE isn't making a manufacture only recommend the thinnest oil possible. Increasing the viscosity is always going to provide more MOFT. That's a basic physics result of an oil film between two moving parts.

 

[97K15004WD]

People like SUV’s as long as gas is cheap.

What I quoted is missing words - what words!?!

 

[ZeeOSix]

Everyone knows Australia works differently though, have you seen their toilets flush?

All the journal bearings rotate in the opposite direction too ... specially built engines.

 

[ZeeOSix]

Just fill the crankcase with MMO, it is at least as thick as 0-8

Searching this comes up with MMO around KV100 of 2 to 3 cSt, so quite a bit thinner. I bet someone has ran an engine on pure MMO like some click-bait YouTubers have ran engines on all kinds of stuff like pure WD-40 etc. Looks like WD-40 also has a KV100 around 2.5-3 cSt. The car the YT's ran on pure WD-40 lasted a lot longer than I'd think, but it did finally blow-up with massive abuse.

 

[JunkdrawerDog]

In the early 70s, my winter blend was 4 quarts of 10w-30 and 1quart Marvel Mystery Oil. Worked for sub zero starting temps.

 

[JackWildfeuer]

My Mom and dad had something like 5 or 6 free oil changes at the dealership for their new Rav 4 when they purchased it. To make a long story short they where not having 10,000 mile oil change or 1 year OCI. So when the oil would hit 5000 miles dad would drain the oil and refill with Mobil 1 5W30. They would then return to Toyota at 10,000 miles for the free oil change.

Once those 5 or 6 oil changes where done dad just went to 5000 mile OCI and Mobil 1 5w30 and Valvoline Restore and Protect 5W30 and has not looked back. They live in Arizona and have not seen any reduction in fuel ecconomy going to synthetic 5W30!

 

[ARB1977]

Those tight clearances must not be that tight after all

That’s what she said.

 

[JackWildfeuer]

That’s what she said.

As I understand it out of all of the engines Toyota has ever built and sold in North America the V8 2UZ-FE has/had the closest clearances and tightest tolerances of all of the engines including everything built up to this post as of 6/22/2026. So this is second hand info from mostly Technicians that I am still friends with but are again not representatives of Toyota and not part of Toyota's engineering team. Most are dealership employee's with only 2 of them working for Toyota directly. So do not quote me.

Normaly when people start babeling(sp) about CLEARANCES they are parroting what they heard froms omeone else and often that person is not even a technician or engineer and has not even looked at a vechile service manual to look up bearing clearances let alone compared say 3-4 engines from that OEM from say 1980's, 1990's and 2020's to actualy make an intelligent statement.

I bet I could remanufacture a 4KC OHV Solid Lifter I4 from an 1982 Toyota Starlet to OEM specifications and it would live a long happy life on everythng from 0W20 to 15W40. My Singer Sewing machine uses 0W8 and that is how I am going to keep things. LOL When a system wont that is a sign of bad engineering and manufacturing. Keep in mind there are machines that ran on peanut oil and where lubed with peanut oil that have only been rebuilt every 100 years or so and I use the word rebuilt loosely!

 

[JackWildfeuer]

It is the classic "What is progress, What is better?" question.

 

[ARB1977]

I’ve got enough 0W20 and 5W30 to make a franken brew. Both are M1 EP. It’ll be about 4 oil changes worth. 1 jug of 5W30 and 2.5 arts of 0W20. Till all the 0W20 is used up. This will be going in the Tundra…unless my original engine has other plans.