High Torque/Low RPM.....which oil?

[BigJohn]

Ok....so I am "Post Happy" today. Here is my second question.

If one has an engine that spends most of its time in the low RPM, Torque area....what is the best oil?

I have a 4 Runner with the 4.0L 6 cylinder. We drive a lot of 55mph and 60mph roads where the truck hangs about 1,800 RPM's in overdrive. Also, I sometimes tow a motorcycle trailer and a small utility trailer. We also do some 'light' 4-wheelin with this thing.

So, I got to thinking.....is a 20wt oil really the right thing for an engine that hangs around in the low RPM's most of the time?

I have a 7 year, 100k waranty and plan to keep this guy a while. I want the engine to be the last thing to wear out.

I wonder if other Toyota 4.0L owners are happily running oils like.....

Castrol Syntec 0W30 (GC)
Shell Rotella T6 5w40
Mobi 1 0W40

What do you think?

 

[Doug Hillary]

Hi,
BigJohn - What oil specs are called for in the Driver's Manual?

 

[901Memphis]

Use a top brand synthetic of the appropriate weight to keep the warranty. Stick with the OEM filter too for the sake of the warranty issue.

No sense in losing out on the warranty!

 

[BigJohn]

Originally Posted By: Doug Hillary
Hi,
BigJohn - What oil specs are called for in the Driver's Manual?


The owners manual states the the typical.....something like, 5w30 is recommended, but can deviate to 10w30. Also, a Toyota Service Bulletin allows me to use a 20wt.

Currently, I have PU 5w20 in the rig and it seems to like it.

But.....can someone answer my bigger question.... If one tends to be in situations where the engine is 'lugged', is it better to have a heartier oil in the sump?

 

[FZ1]

Synthetic is better for this application. It's a better oil. Never good to "Lug" an engine. Consider towing in the next highest gear.

 

[sangyup81]

Originally Posted By: BigJohn
Originally Posted By: Doug Hillary
Hi,
BigJohn - What oil specs are called for in the Driver's Manual?


The owners manual states the the typical.....something like, 5w30 is recommended, but can deviate to 10w30. Also, a Toyota Service Bulletin allows me to use a 20wt.

Currently, I have PU 5w20 in the rig and it seems to like it.

But.....can someone answer my bigger question.... If one tends to be in situations where the engine is 'lugged', is it better to have a heartier oil in the sump?

If we're talking about towing, use a heavier oil like a 10w30 or a 15w40. The real problem with towing is your transmission fluid. If you don't have a cooler, I'd change it out as soon as you're done with the towing

 

[Steve S]

Originally Posted By: Doug Hillary
Hi,
BigJohn - What oil specs are called for in the Driver's Manual?
OOOOOOOOOOOOh!

 

[rslifkin]

This type of situation is why I run a 5W-40 HDEO in the Jeep, rather than the recommended 10W-30 or 5W-30. I figure the extra protection is good, considering it will lock the TC in OD down to 1100 rpm. And it pulls pretty hard even lugged down that far, so that can't be too easy on the bearings, considering it's just above idle pressure (30 lbs at hot idle) at that RPM.

 

[pidster]

Originally Posted By: rslifkin
This type of situation is why I run a 5W-40 HDEO in the Jeep, rather than the recommended 10W-30 or 5W-30. I figure the extra protection is good, considering it will lock the TC in OD down to 1100 rpm. And it pulls pretty hard even lugged down that far, so that can't be too easy on the bearings, considering it's just above idle pressure (30 lbs at hot idle) at that RPM.


Do the same in my Ranger. Noticeably quieter than factory fill or PYB to the point that my best friend, a regular in the passenger seat commented on it before I even told him what I did. As for warranty, I see several other vehicles in the OP's signature. Surely some of those oil receipts can be saved wink wink.

 

[spasm3]

i don't run the 20wt in my escape,for the same reason. If i tow anything especially in the summer, i don't want to gamble on the 20wt. The t-6 5w40 in the summer runs great,i use 0w 30 mobile in the winter.

 

[BearZDefect]

My opinion:

It's hard (if not impossible) to lug the engine with a modern automatic transmission, the programming won't let that happen.

1,800rpm isn't too low of an engine speed.

Ford recommends 5w-20 in heavier trucks than this one.

If you're worried about the engine, use ?w-30 per the manual. I wouldn't bother with ?w-40 in this application. 5w-20 is so much less viscous than 5w-40 at winter startup temperatures.

Towing in overdrive is fine if the TCC remains engaged. If the TCC repeatedly disengages, or is disengaged for extended periods then the transmission could overheat. You can always switch off overdrive for significant uphill climbs and leave it on the rest of the time.

I don't own a Toyota, never have, so I'm generalizing.

 

[The_Eric]

Originally Posted By: BearZDefect
My opinion:

It's hard (if not impossible) to lug the engine with a modern automatic transmission, the programming won't let that happen.

1,800rpm isn't too low of an engine speed.

Ford recommends 5w-20 in heavier trucks than this one.

If you're worried about the engine, use ?w-30 per the manual. I wouldn't bother with ?w-40 in this application. 5w-20 is so much less viscous than 5w-40 at winter startup temperatures.

Towing in overdrive is fine if the TCC remains engaged. If the TCC repeatedly disengages, or is disengaged for extended periods then the transmission could overheat. You can always switch off overdrive for significant uphill climbs and leave it on the rest of the time.

I don't own a Toyota, never have, so I'm generalizing.


You pretty much took the words out of my mouth, err keyboard.

 

[jstutz]

i have wondered this myself, more theoretically than practically. My though would be in a lugged engine or lightly lugged engine the extra anti wear additives in a HDEO would be beneficial. Also i can see how the higher viscosity could be desirable in most cases. The only thing that i think might make the thinner oils a better fit is some parts of an engine rely on splash lubrication. The higher viscosity HDEO's will generally not splash as easily as the thinner SM oils. Just my thoughts but i would love to get some good feedback on this. I think it is a pretty interesting topic. On the other hand, most big diesels are slow running, high torque engines and they live a long time on HDEOs. Maybe this is a clue. Also, it is probably different for different engines. Like you said if your engine has inherently low oil pressure by design, the answer may be different than ones that maintain higher pressures throughout the rpm range.

 

[BigJohn]

Great replies and I want to thank everyone. You have my mind thinking further and harder about oil choice.

But.....let's stay with this theoretical discussion....

jstutz response above is what I am getting at and would also like further discussion.

 

[addyguy]

Toyota recommends, at least in Camry manuals, that is you are towing or working the engine hard, a move up the viscosity range may be appropriate.

Manual wants you to use 5W-30...so try a thick 5W-30, like a HM oil - Maxlife 5W-30, for example.

 

[il_signore97]

Originally Posted By: BigJohn
Ok....so I am "Post Happy" today. Here is my second question.

If one has an engine that spends most of its time in the low RPM, Torque area....what is the best oil?

I have a 4 Runner with the 4.0L 6 cylinder. We drive a lot of 55mph and 60mph roads where the truck hangs about 1,800 RPM's in overdrive. Also, I sometimes tow a motorcycle trailer and a small utility trailer. We also do some 'light' 4-wheelin with this thing.

So, I got to thinking.....is a 20wt oil really the right thing for an engine that hangs around in the low RPM's most of the time?

I have a 7 year, 100k waranty and plan to keep this guy a while. I want the engine to be the last thing to wear out.

I wonder if other Toyota 4.0L owners are happily running oils like.....

Castrol Syntec 0W30 (GC)
Shell Rotella T6 5w40
Mobi 1 0W40

What do you think?



BigJohn,

I have one vehicle with a Toyota engine (Pontiac Vibe, aka Matrix). I have a bunch of different other vehicles. I regularly tow a 1,500 lb trailer with several vehicles in my fleet, and sometimes tow up to 4,000 lbs with my Chev Venture only. Here are my observations over the years. Take them for what they are worth:

I had a 1996 Chrysler Intrepid (Chrysler in Canada, Dodge Intrepid for all of the Americans here!) I regularly towed that 1,500 lb trailer with it since new. I racked up 350,000 km on it using nothing but synthetic 0W30. The owner's manual suggested 10W30 during warmer periods, and 5W30 during colder periods. I always used the 0W30 synthetic (it was the old Amsoil TSO Series 2000 0W30 btw). The engine ran perfectly up to 350,000 km when I sold it after 11 years due to many many front end suspension issues. Never a problem there, however, I should add that while the engine definitely had to work harder to tow the trailer, I never felt that I was asking too much of it.

Fast forwarding to now, I regularly use the Vibe (1.8L Toyota engine, with 5-speed manual tranny) to tow the same trailer now. I do find it more than adequate most of the time, but sometimes, uphill especially, I have to downshift a couple of gears just to maintain speed. Sometimes, I'll be in 3rd doing 55-60 mph just to climb a hill with it, and my foot will be pretty much to the floor for the whole way. Even so, the car still slowly loses speed up to the top of the hill, but at 4,500 rpm, I can't exactly use 2nd unless I slow down quite a bit further. So in this case, I feel better upping the oil viscosity to a 40 grade from the recommended 30 grade. I have also installed a custom oil to coolant heat exchanger (which your 4-runner should already have from the factory).

The only reason I've moved up a grade is due to the fact that I have to keep the pedal floored (or nearly floored) while climbing grades while towing. Otherwise, I would have stayed with a 30 grade as I do in my other vehicles.

My Chev Venture never seems to need to be floored, even when towing 4,000 lbs, so I stick with a synthetic HDEO 5W30 for towing. This vehicle does not have the towing package from the factory, and I have not added the oil cooler to it (although I definitely have added the auto tranny cooler - a nice large one out front in addition to the stock heat exchanger in the rad).

Hopefully that helps your decision. I would say that if I had your vehicle, I'd likely be happy with a robust 5W30 synthetic and call it a day.

 

[BigJohn]

Originally Posted By: il_signore97
...so I stick with a synthetic HDEO 5W30 for towing.



signore97....great comments.

Wow I wish I could get my hands on a synthetic HDEO here in Colorado. That would probably be my choice!!!!!

 

[meep]

There's a quote above that suggests towing in OD is ok if the TC stays locked. I've read conflicting statements on that, I think it's more of a gray area.

OD gear places more force on the smaller driven gear than say 3rd (or 4th in a 5spd), yielding higher stress on teeth and lateral forces on driven shaft. The higher pressures here will also heat the oil. The impacts of this will differ based on AT design, such as a honda that uses a MT configuration, which would certainly be applicable here, or an older typical auto using planetaries. I certainly have own planetary AT's that said not to tow in OD.

Me-- I've done both. If it's a large trailer, I'll shift down one. If it's a lightweight with small frontal area, I don't bother.

As above mentioned, 1800 rpm at the engine is fine.

 

[mechtech2]

Big John -

In the past, in general, low RPM engines favored thicker oil .


These were larger V8s with older mfr. processes and older oil technology. Those with skinny/narrow bearings were more troublesome [small block Ford , cough, cough].

Today, the mfrs. recommendation is a good place to start.
It really is.

Remember that at low RPM,you are not producing full power, so the load on the bearings is not greater than at high RPMs.

 

[OVERKILL]

Originally Posted By: mechtech2
Big John -

In the past, in general, low RPM engines favored thicker oil .


These were larger V8s with older mfr. processes and older oil technology. Those with skinny/narrow bearings were more troublesome [small block Ford , cough, cough].

Today, the mfrs. recommendation is a good place to start.
It really is.

Remember that at low RPM,you are not producing full power, so the load on the bearings is not greater than at high RPMs.


My cam grinder ran 5w20 in a stock-bottomed 302 that he spun to 7K. Bearings looked fantastic on tear-down (he buggered the thrust bearing when his clutch failed) after 40,000 miles.

Oil is a lot better quality than it was when that engine was new.

I've run everything from 0w20 to 5w50 in my one 302 and it doesn't seem to care. Runs the "best" on a 0w40.

Or are you talking about the 351W with the huge 3" mains?