Motor oil grade: Flow vs pressure.

Some of the most common problems with modern engines today has to do with cam phasers and timing chain tensioners including the Tundra. My 2017 tundra has the cold start rattle and I can only assume it's the timing chain slap. I was thinking one day about this and considered it might be related to oil pressure. I'm not saying there is anything wrong with the pump but pressure is affected greatly be the fluid viscosity. This is also true for blood pressure in us. If we are dehydrated, our blood will be thicker and our blood pressure will be higher. In an engine it must be the same. Easy flow... low pressure. Timing chain tensioners and cam phasers are both operated by oil pressure so it seam logical that if I increase the viscosity of the oil, the pressure will increase and the tensioner, which is a piston, will exert more force on the timing chain. Also, if an engine has more than 100K miles on it, the clearances in the main and rod bearing will be a bit larger. This will also make the oil flow easier and therefore reduce the oil pressure. To me, it makes sense to upgrade my oil to 5W-30. Am I totally wrong in my thinking here?

 

There is a lot that goes into this, and I encourage you to do your own research. But a couple points to consider.

1) The oil pump is a positive displacement pump, meaning flow (volume) only changes with RPM. The viscosity of the oil has no impact on flow volume, pressure will go up with viscosity though.
2) The FSM for the 3UR specs ranges from 0w20 to 20w50.
3) No one really knows why some of these trucks develop the chain tensioner issue. Regular oil changes and oil viscosity choice do not appear to have an impact, as its happened to people who get regular oil changes. This issue also exists in the Toyota V6s that have a similar design.
4) The chain rattle happens on cold starts when the oil viscosity is highest, so higher viscosity is unlikely to help. A member on here recently tried switch to 5w30 after he developed chain rattle on 0w20, it made no difference.

So the above is mostly just data points to consider. My opinion is that the chain rattle is probably due to a combination of design/manufacturing variability/maintenance/driving style....aka bad luck. Personally I wonder if deposits build up in the tensioner and that causes it to stick in some trucks and not others. I think the best course of prevention is keeping the oil system clean with regular changes and good oil. Possibly consider running the new-ish Valvoline Restore and Protect or some other oil system cleaners periodically. Not sure there is much you can do beyond that.

 

Thanks Pman. I change my oil every 3000 miles. The way car and truck prices are these days, I'd like to keep my truck for as long as possible.

 

I just found this. Not sure what it means to us but... https://forum.ih8mud.com/threads/update-5w-30-heavier-recommended-rotw.1215433/

 

You said it man.

 

I switched to 5w30 after my 2nd oil change and it made a world of difference in noise. This motor used to have 5w30 as the factory oil I believe before the government mandated bs took over. The 5.7 in other countries is factory with 5w30 and can take up to 15w40 I think in the manual.

 

This^^^
I switched to 5w30 about 5-6 years ago (my free 0w20 oil supply dried up) and the difference in engine noise is amazing so much quieter
I did kind of an oil system flush a couple years back. I ran 6 qts 0w20 and a qt and a half of atf for about a thousand miles. I forgot how noisy the engine was with 0w20

 

It echoes what most on here and myself believe, which is the choice to spec 0w20 in the 3UR is related to CAFE regs, not longevity.

This is from the factory service manual for our trucks with the 3UR, just like the US spec 200 series 'cruisers. And no the engines are not different for Mexico.

While the reduction in valvetrain noise is a nice benefit of heavier oil, its important to note two things.

1) There is no evidence to suggest that the increased noise from using 0w20 is meaningful in terms of engine life or engine wear.
2) There are at least two 3UR powered Tundras that have gone over 900K miles on 0w20.
https://www.youtube.com/watch?v=Ttt11sio4-I
https://www.carscoops.com/2024/06/2...tedly-goes-878987-miles-in-under-seven-years/
Also this crazy UOA report on a severely overloaded Tundra
https://bobistheoilguy.com/forums/t...20-16-tundra-6-175-miles-heavy-towing.312638/


That said, I run Mobil 1 FS 0w40 in my 3UR.

 

The timing chain tensioner is operated by oil pressure. The timing chain rattle happens on cold starts. 0W20 pumps faster than 5W30 when cold so the tensioner should snug the chain quicker with 0W20 than with 5W30.

I worked for a company that manufactured oil and there is not a tremendous viscosity difference between 0W20 and 5W20.


I have been driving Toyotas since 1979 and I never thought I knew more about Toyotas than a Toyota engineer. I use 0W20 as recommended.

 

The most important thing is regular, timely oil changes regardless of oil choice.

 

Fortunately for us, the Toyota engineers have told us (via the FSM) that running up to 20W50 is fine in these engines.

Sturgill Simpson said it best: "Motor oil is motor oil, just keep the engine clean..."

 

The problem is the US government thinks they know better than Toyota actually. Since the same 5.7 in a Tundra in Mexico can run a whole slew of oils according to Toyota. It's only in the USA due to CAFE standards that require running 0w20 to try and increase MPG. This is from the Toyota TIS site it self.

 

Proof that engineers don't decide what goes in the owners manual: lifetime fluid.

 

It's to bad Toyota has no say in what type of oil they recomend. Toyota is the new GM "Government Motors".

 

No, it has to do with CAFE standards that require manufacturers entire fleet to meet a certain MPG as a whole so by requiring 0w20 it may only increase MPG by .5mpg but that adds up when you get .5mpg better out of 20+ different models. I'm just making up the .5 number but that's how CAFE standards work but that's why 0w20 is the only spec for the USA so that they can meet that standard. The standard gets more strict every year which is why you see the lack of V8s and more turbos. It's about efficiency more than reliability now. Hopefully the next 4 years changes that.

 

To bad Toyota doesn't get a choice in what oil to use. It's to bad they are forced by the government to use 0w20.

 

a while back I posted my comparative Blackstone reports.

5w-30 protects my engine better than 0w-20

tested.

verified.



YMMV.


that being said....oil don't matter....just make sure it's full and you change it regularly.

 

Buddy, calm down. No one said I think the Government runs Toyota. What the government does do is sets standards that auto manufacturers need to comply with. I also didn't say 0w20 wasn't safe to use either. What I am pointing out is the the same exact vehicle in Mexico according to Toyota can run a bunch of different viscosity oils, not just 0w20. Would you care to explain why if it's not due the the CAFE standards? 0w20 will produce better MPG because it has a lower viscosity, 0w20 will also cause wear faster than a high viscosity oil. The 3UR can run 20w50 according to Toyota, as long as the environment calls for it. Instead of yelling on a forum just do some research. Here is some screen shots to get you started, one is Toyotas TIS systems oil recommendations for oil and the other is what CAFE standards are. The CAFE standards get stricter as time goes on, that's why Toyota no longer has a V8 in the US and also has more hybrids. Don't you think Toyota would love to sell the new series 70 Land cruiser here in the states? But it only has a V8 or a diesel.

 

LoL i give up. US goverment has made Toyota use 0w 20. Toyota is forced to use it.

 

Sir I think you have no idea how the CAFE standards work. One vehicle does not meet or not meet the standards. It is the manufacturers entire fleet, so Toyota could have a V8 Tundra in its fleet since it has the Prius and other small hybrid models to offset it. The entire fleet needs to meet a certain MPG total. So if Toyota can shave .5mpg off by running 0w20 it's worth it but it's definitely not the best oil for protection, just the best oil to get the best mpg, do you think 0w16 oil exists to help protect engines? The majority of people have no need for the cold starting flow of 0w20 unless maybe you are in Alaska. Project farm did a test recently that shows 5w30 will provide better protection over 0w20. I could care less what people put in their truck, I just try to put the facts out there for people to see, 0w20 is not the only oil that Toyota specs for the 5.7, it's just the only oil spec for the USA and Canada. Everywhere else in the world the Land Cruiser with the same engine can run all those different viscosities that the Mexican Tundra can.

 

Well this looks like a fun thread.... I just changed my oil at 125k In Central Texas. I went with 5w30. I will send the oil off to Blackstone at 135k and check for changes to 0w20. Change my oil every 5k.