Xw-30 vs similar viscosity at 20F

[Jimmy C]

For xW-30, what would x have to be if the oil was to have a similar viscosity at 20F as SAE 30 does at 212F?

My 72 Pinzgauer manual says it is supposed to use SAE 30 in the summer and SAE10 in winter. I do not believe they had multigrade oil when it was built. I want to use the same multigrade year round. My oil temperature is a bit above 200F after warm up and my coldest mornings are around 20F.My guess is that the viscosity of SAE 30 at 212 F degrees is probably the ideal viscosity because that was what the manufacturer speced when they did not have to worry about cold weather starting. But what would x have to be if the oil was to have a similar viscosity at 20F as SAE 30 does at 212F?

 

[blufeb95]

No oil that I know of would be ~10CSt at 20F and be thick enough to use in an engine at operating temp. if 20F is your low temp even modern SAE30 is probably fine enough most now are made with a decent hydro treated base that probably meets 15W or 20W, but any decent multi grade should be fine too, is that an air/oil cooled motor? I'd probably consider something heavier like 10W40 or even Mobil 1 15W50.

 

[Jimmy C]

It is air cooled with a thermostatically controlled oil cooler. The oil temp stays right above 200 once warmed up no matter what. Why would you use something heavier than the manufacturer recommends?

 

[blufeb95]

That's probably a fairly old manual, I seem to recall more recent air/oil cooled Porsche engines typically recommend 15W50 or 20W50..

 

[twX]

There is no oil grade that will be the same viscosity at 20F as an SAE30 is at 212F. Well, maybe WD-40. All oil grades are much thicker than they need to be when they're at ambient temperature, and that's just fine so long as the oil is still pumpable.

The SAE 10 recommendation is due to concerns about an SAE 30 being unpumpable on cold starts in freezing weather. The SAE 10 might result in more engine wear compared to an SAE 30 once the engine warms up, but that's preferable to the complete engine failure that might occur after a cold start.

Just use a 10W-30 or 15W-40.

 

[Wireman1987]

I’d go with a 10W30

 

[facility1]

just go to Walmart and get 10w-30 high milage Valvoline MaxLife. or ep Valvoline extended. high milage as this is a excellent oil.

 

[fantastic]

My 72 Pinzgauer manual says it is supposed to use SAE 30 in the summer and SAE10 in winter.

Those two mono grades are essentially today's 5w-20 or 5w-30 multi-grade. You'll have the benefit of using one oil grade.

 

[blufeb95]

I’d go with a 10W30

From what I'm reading many people have consumption issues using thinner multigrades in these engines, and it's best to stick with Monograde, or use a good 10W40 or 15W40, or 15W50 or 20W50.

 

[Wireman1987]

From what I'm reading many people have consumption issues using thinner multigrades in these engines, and it's best to stick with Monograde, or use a good 10W40 or 15W40, or 15W50 or 20W50.

Never mind had c and f chart mixed up

 

[Japanese]

I do not believe they had multigrade oil when it was built. I want to use the same multigrade year round. My oil temperature is a bit above 200F after warm up and my coldest mornings are around 20F.

Where do you live and what is the temp. in the summer?
200°F is not a high oil temp. Is it the same in the summer too?

 

[Jimmy C]

I live in western North Carolina. Highest we ever see is about 80F. Oil temperature after warm up is always about the same. There is a thermostatically controlled oil cooler with forced air blowing across it. Plus’s it has a huge sump. 8 quarts on a 90 hp motor.

 

[Jimmy C]

That's probably a fairly old manual, I seem to recall more recent air/oil cooled Porsche engines typically recommend 15W50 or 20W50..

Manual written I. 1972

 

[Japanese]

I live in western North Carolina. Highest we ever see is about 80F.

There is a Facebook group called Pinzgauer:
https://www.facebook.com/share/g/1BmWkkhTa9/

In the following thread (below) the people discuss what oil to run in Pinzgauer that is operated in Texas. They recommend to owner to run SAE40 mineral/conventional oil because it runs cooler than multigrade oil. Some people suggest to run 20W-50 oil. But again that is for person who lives in Texas.


Here is what Valvoline offers as conventional VR1 oils - 10W-30, 20W-50, SAE30, SAE40, SAE50, SAE60:
https://www.valvolineglobal.com/en/vr1-racing-oil/
The 10W-30 oil has zinc 1100 ppm and phosphorous 1000 ppm.
The SAE30 oil (and all other VR1 oils) has zinc 1400 ppm and phosphorous 1300 ppm.

In your case if you want to run one oil year round and the temp. in your area is 20°F (winter) - 80°F (summer), I would choose:
a) 10W-30
b) 10W-30 (winter) and SAE30 (summer)
Also, stay away from synthetic oils.

Found this video on youtube and there are very cool shots of the undercarriage, the diffs and transfer cases of that same truck:

 

[Jimmy C]

Thanks for all the comments. Am I incorrect in thinking that on a cold day thick oil would mostly get dumped out the pressure release valve on start up? Is 10W-30 likely to do this at 20 degrees F? I do not want to have that happen.

 

[Astro14]

Thanks for all the comments. Am I incorrect in thinking that on a cold day thick oil would mostly get dumped out the pressure release valve on start up? Is 10W-30 likely to do this at 20 degrees F? I do not want to have that happen.

On a cold day, the 10W30 is far less likely to do that than the straight 20.

Stop overthinking this. A multi grade will be fine in this.

The multi grade will perform better, because it is better, than the oil that was specified when this was built.

 

[CleanSump]

When the manual was written multi-grade oils were relatively new and the main consumer of the vehicles were European militaries who were still using the old 10 in Winter and 30 in Summer routine. They were slow to update. We still used barrels of straight 10, 30, and 40 oils in our deuce and halfs in the Marines clear up into the 80s that I personally know.
My dad used 10 in Winter and 30 in Summer in Minnesota back in the early 60s. It was surpassed in the mid/late 60s when multigrades became common.
Just use a multigrade and enjoy a simpler life. Any name brand rated oil you buy today will be better than when the vehicle was made.