What is the lowest temp you all would use 20w50

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Originally Posted By: tig1
Originally Posted By: Shannow
Originally Posted By: DoubleWasp
20/50 is slow to flow under freezing conditions, but not a death sentence for an engine.


Pumpable, and it still gets there at the same time...

https://bobistheoilguy.com/forums/ubbthreads.php/topics/36793/Shell_Helix_Sport_50_-_datashe



Maybe the same oil pressure, but not the same flow to the cam area. Much slower in very cold temps. Heavy oils can also cause the ADBV in the filter to prevent oil flowing through the filter for several seconds.


Note, we are talking the limits of 20W50, and my experience with 25W70 at -5 to -7C...not "very cold temperatures", where I always maintain that an appropriate for the weather conditions "W" grade be.

As to the continued "0W" equals flow equals start-up wear protection meme, here again is some testing that was done on an engine with a couple of different grades, in and around their lower temperature limits of pumpability.

Oil%20gallery%20fill%20and%20rocker%20time.jpg


At freezing, the SAE30 got full oil pressure, and flow to the rocker arms at 32F at exactly the same time as the 5W20 did at 10F...that's the mechanical filling capacity being filled with oil...when both cases were lowered, yes that case that you describe DID occur with oil pressure early and the rockers taking longer to get oil.

Again, this question is about what are the limits of operation of the 20W50 grade, NOT what oil is appropriate at "very cold" conditions.

MRV, the test for ability to flow to the pickup is at -15C.
CCS, the Cold Cranking Simulator is -10.

So I still stand by -10 as being the limit, and still stand by my statement that it's a grade that I don't use.
 
Oh, and aren't Oil Pressure senders usually on the engine side of the filter ?

If so, then no flow through the ADBV, no oil pressure.
 
Originally Posted By: SR5
I've used 20W-50 from about -5C to +45C without problems. To be honest, I didn't know there was any other grade of oil for years.


Same here. As a Ford dealership mechanic in the 90's, we used it in EVERYTHING, from 1.3lt Festivas to 5.8lt V8's, with no issues. I'd happily run it in my Falcon. The US guys seem to think 20w50 is like tar! I cringe when I read recommendations for 5w30 in, say, a GM 3800 engine - to me, that's a 20w50 engine all day long
smile.gif
 
Originally Posted By: hpb
The US guys seem to think 20w50 is like tar!


there's a couple of vocals who use the term "engine molasses", and "tar" having no idea what they are talking about...gets a certain amount of traction with the then unknowing.
 
Originally Posted By: Shannow
Originally Posted By: hpb
The US guys seem to think 20w50 is like tar!


there's a couple of vocals who use the term "engine molasses", and "tar" having no idea what they are talking about...gets a certain amount of traction with the then unknowing.


............. for they have not seen one physically , let alone use one in an engine.
 
I ran 20W50 Castrol in a '79 Caprice 305 V-8 year round in Northern Alabama as well as South Texas.
Temps in Bama could drop well into the teens and never once was there a problem in ten years of ownership. I sold it with 135K and it still ran as new. The potential buyer brought his mechanic with him who stated he would buy the car if the other guy did not. I purchased it new and was also used to tow for thousands of miles. So much for "the big scare" about 20W50 in the cold (not Arctic) temperatures.
 
My rx7 manual says 20w50 is good down to 10 degrees and 10w40 is good down to -10 degrees. A lot of rotary guys around here run it year round no issues with start up or long cranks. Of course we don't often get below 10 degrees and even more rarely get below 0.
 
Back in teh day, I ran 20W-50 year round in Claifornia in many vehicle. Never an issue. Did not use it in cars going to the Sierra to ski though.

Cars and trucks going to ski were usually 10W-30 as it can get to minus F numbers in Truckee during ski season. Fired the Volvo 244 many times at Kirkwood at 0*F on 10W-30 w/o issue.

20W-50 was common oil in cars and trucks in our family out in the country on the farm in the Santa Cruz mtns where it regularly gets to 25*F in the winter. Never an issue firing those vehicles.

Some of the old 6-volt Ford flat-heads and some of the tractors were not wanting to spin too fast at 25*F. But with a bit of coaxing, they'd light and off we'd go
smile.gif
 
Originally Posted By: mazdamonky
My rx7 manual says 20w50 is good down to 10 degrees and 10w40 is good down to -10 degrees. A lot of rotary guys around here run it year round no issues with start up or long cranks. Of course we don't often get below 10 degrees and even more rarely get below 0.


20w50 dino was what I ran in my rotaries and Castrol GTX 20w50 in the '93 Twin Turbo was what it liked the best. This was in Georgia but for a summer only car, I would use it anywhere in the world. If you drive a rotary year round however (bless your soul), I would certainly feel comfortable even with something like a 10w30 Rotella in winter just about anywhere in the world.

Rotaries are an odd bird. If I HAD to drive a fuel injected rotary here in the Arctic, I would delete the OMP, pre-mix the [censored] out of my fuel and run a full synthetic 0w40. You could just run the 20W50 year round with a frostheater and battery blanket installed but if you couldn't plug in, you're screwed. Of course watching somebody trying to navigate even a stock FD RX-7 on studded snow tires wouldn't probably still get stuck in 15 minutes so it's probably a moot point.
 
Originally Posted By: mazdamonky
My rx7 manual says 20w50 is good down to 10 degrees and 10w40 is good down to -10 degrees.


Yep 20W-50 down to 10 F (negative 12 C) sounds about right to me.

For many years my favourite oil was Penrite HPR 20W-60, I used it in everything.
 
starting after -20F my father used to slip a tray of hot coals under the pan...but that's back when cars were old at 90k
 
Originally Posted By: zeng
Originally Posted By: Shannow
Originally Posted By: hpb
The US guys seem to think 20w50 is like tar!


there's a couple of vocals who use the term "engine molasses", and "tar" having no idea what they are talking about...gets a certain amount of traction with the then unknowing.


............. for they have not seen one physically , let alone use one in an engine.


Are you saying Americans have never seen 20w50 let alone use it in an engine?

It's available virtually everywhere and most here have used it or seen it used plenty they just don't anymore because of changing specs and more choices. Ever been here before?


Originally Posted By: Shannow


Here's a worked 3.8 (265hp) on M1 15W50...

https://www.bobistheoilguy.com/forums/ubbthreads.php?ubb=showflat&Number=2446765


Apples and oranges. I could show you a thousand videos of actual performance cars in the US on M1 15w50 or Ford's with 0w50 or insert another thick oil. That grade is good at dealing with high heat boosted applications. It doesn't have anything to do with the original question of how cold is too cold for a 20w50.
 
Originally Posted By: NormanBuntz
Originally Posted By: dblshock
starting after -20F my father used to slip a tray of hot coals under the pan...but that's back when cars were old at 90k


This is a new one on me.


It's new because it's really old and hasn't been necessary for 70 years. 6 volt electrical systems, no block heater, straight 50w in the sump....people got creative.
 
Originally Posted By: jayg
Originally Posted By: Shannow


Here's a worked 3.8 (265hp) on M1 15W50...

https://www.bobistheoilguy.com/forums/ubbthreads.php?ubb=showflat&Number=2446765


Apples and oranges. I could show you a thousand videos of actual performance cars in the US on M1 15w50 or Ford's with 0w50 or insert another thick oil. That grade is good at dealing with high heat boosted applications. It doesn't have anything to do with the original question of how cold is too cold for a 20w50.


Take much out of context ?

I was responding to the bemusement displayed by others that GM specced 20W50 for my L67, demonstrating that it's not a bad choice...not commenting on the OP's question of how cold's too cold for a 20W...which I addressed also in other parts.

As to your reply to zeng...do YOU refer to 20W50 as molasses or tar ?

His comments and mine were regarding those statements, and where they typically come from.

If you don't then again, you've taken it out of context.
 
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