Oil weight in an FZJ-80

[Schattenjager]

I just ran across the notion that the 5-30 oil weight recommended in my owner's manual is for the USA only. All other markets recommend that the owner use 20-50 - a huge difference!

Can anyone not in the USA check their manual to see what the recommend oil weight is in your market?

I am considering making the change. I have Mobil 1 5-30 in it now and may very well change to Mobil 1 20-50 on a motor with 200K miles.

What say you about this?

from the source:

"This has been a major source of controversy. For U.S. spec vehicles, Toyota recommend 5w-30 for most conditions and 10w-30 for extreme hot
conditions. However, this likely has less to do with what is best for engine longevity and more to do with fuel economy. The lighter oil just barely
improves fuel economy and the government mandates that manufactures recommend an oil that is fuel saving.

However, in Australia where the weather is mild to hot and there is no such fuel economy requirement, Toyota recommends a 20w-50 type oil.
One has to assume the heavier weight oil is better for the engine, but more research and debate is needed."

 

[luk4mud]

Lots of debate on mud about this. Based upon multiple positive posts there, I have been running the 15W-40 diesel oil plus Napa or Amsoil (Mann) filters. The 80 seems to really like it.

 

[Cackalak Han]

I haven't heard of any engine issues or poor UOA results using 5w-30 in just about every gas engine in the states (with regular OCI's).

 

[Schattenjager]

Not that my thoughts mean much, but there might be a few good reasons to go heavier with the oil:

1) Warmer weather is here so the thick oil won't make much difference in cold startup. I run Mobil 1 anyway, so I imagine even cold temps would not be much of a concern, especially with an oil pan heater.

2) The heavier oil may reduce oil consumption. I'm burning a little oil, as most cruisers do, but theorize that a thicker oil would help create a better seal around the oil ring on the pistons and would be less likely to go into the combustion chamber.

3) If #2 is correct (Austin Powers anyone?) then would it not stand to reason that performance might take positive turn? Oil burns, but is not as combustable as petrol, so I would think that it would hamper the power by diluting the fuel / air ratio. If the oil stays in the proper place, and the rings seal up a little better, then surly the truck would run more efficiently than it has burning the thinner stuff.
:snorkel:

4) Lastly, engine durability would be enhanced by the superior shock and temperature performance of a thicker oil. My question here is: do mechanical parts 'get used to' things? Meaning: will going to a thicker oil in any way hurt the oil pump after it has pumped thin oil for so long? I doubt it, but stranger things have happened.

I'm very interested to see what folks think about this!

 

[MoGas]

Don,

With oil consumption issues on the 80 series, rarely is it from the piston rings.

To be sure, you need to perform a leak down test. If you find that your leak down is good, you will probably want to start budgeting to pull the head and have the valve seals replaced.


When you say "I'm burning a little oil", how much do you mean?


Dave

 

[ntsqd]

Is oil analysis now showing metal in the oil? What I mean is, is the 5-30 not actually keeping the bearings suspended off the crank journals all of the time?

If it isn't, then maybe a heavier weight oil is called for. If it is doing the job, then why change? Run the lightest viscosity oil that will do the job in your particular operating conditions. A high viscosity oil is harder to pump because it is more resistant to flow, which means more wear on cold start-ups. Higher oil pressure isn't an indicator of flow, just the opposite - it is an indicator of resistance to flow.

I run the non LE 15-40 diesel engine oil in everything, but that is mostly due to the couple of cam-in-block engines that I own and their need for a high pressure additive that OHC engines don't need.

 

[Schattenjager]

...When you say "I'm burning a little oil", how much do you mean?

Burning about 1 quart per 3.5K miles. This seems to be normal for this vintage / mileage, yes?

Is oil analysis now showing metal in the oil? What I mean is, is the 5-30 not actually keeping the bearings suspended off the crank journals all of the time?

No analysis has been done. I'm going by consumption and the Levi's Red Tag Meter.
:snorkel:

If it isn't, then maybe a heavier weight oil is called for. If it is doing the job, then why change? Run the lightest viscosity oil that will do the job in your particular operating conditions. A high viscosity oil is harder to pump because it is more resistant to flow, which means more wear on cold start-ups. Higher oil pressure isn't an indicator of flow, just the opposite - it is an indicator of resistance to flow.

I stated a few reason for wanting to change - primarily better piston ring sealing and better wear protection. There is a lot of data that supports the USA requires manufactures to recommend the thinnest oil for the sake of economy. Of course they do not have to pay to repair a vehicle and I doubt any of them are chemical engineers. The fact that Toyota recommends a much higher weight than the US govt. has me leaning on the side of the folks that engineered the Cruiser. That is the extent of my desire to consider a change.

 

[ashooter]

FWIW I run synthetic Shell Rotella-T or Mobile1 15w-40 in both my '92 FJ80 (3F-E engine) and 2002 Chevy pickup. I change the oil every 3000mi or so in the Cruiser and every 5000mi in the pickup. Both seem to love it.

The Chevy was "using" about 1/2 to 3/4 of a quart of oil between oil changes, but once I switched to 40 weight a couple of years (and about 50,000 miles) ago it stopped.

 

[adventureduo]

Burning a quart everyone 3500 i've heard is not all that unusual. In fact... we burn that ourselves. Oh and we run 5 and 10w30 here in Sunny SoCal.

 

[Klierslc]

I have run the gamut over the years, 10w-30, 5w-40 synthetic, 5w-30, 15w-40. I found that the fuel mileage did not vary significantly in mixed driving. However, there was a 2000 foot highway climb that I used to drive regularly--with the 15w-40 I would hit 2nd gear twice during the climb with the cruise on. With the 10w-30 I could pull it in third the whole way.... None of my 80s burned oil until my current one.....Still trying different oils to see what she likes best.

 

[Schattenjager]

Burning a quart everyone 3500 i've heard is not all that unusual. In fact... we burn that ourselves. Oh and we run 5 and 10w30 here in Sunny SoCal.

What brand and type (dino - syn) are you running?

 

[ntsqd]

I don't see that changing the oil's viscosity is going to aid ring seal. If it does change the ring seal then I propose that the engine has big problems.

 

[adventureduo]

What brand and type (dino - syn) are you running?

We were running Amsoil before we sold it, but it got switched to regular oil while it was away.. so i just stuck with generic oil (whatever i grab) now. I figure if we are truly setup for long haul runs through out the country/world i dont want to have to find synthetic. That being said i have spare oil in the back and its Amsoil that i had already... so im all over the place basically.

Our rig isn't a DD either.

 

[Nay]

I always smile when I read these posts - the idea of the big inefficient last forever inline six is that non of these types of issues have any real meaning. On the one hand we hear about how the engine was built to run in 3rd world conditions for 300K miles or more and on the other hand people are getting Blackstone reports and debating viscosity. I mostly think this rig is what it is :smiley_drive:

Having said that, my 80 really likes the 5w-40 Rotella syn, I just run Mobile 1 usually 5w-30 if I can't find it handily. I deal with temps that are about 20 below to 100F throughout a year, and since I only drive my 80 7,500 miles a year (one oil change for me) I use one oil for those conditions.

The point of an 80 is to not have to worry about these things, in exchange for which you get a low power to weight ratio (by modern standards) and 12 mpg.

 

[adventureduo]

Exactly.. Thats why i put in whatever i have laying around. Another reason why i don't spend the money on 92 octane.. that motor doesn't even know what 92 is.