SAFE STARTING TEMPS

[TEXDOG]

Please weigh in with your opinion on safe starting temps F(cold)for these oils:
M1 5/30,5/40,0/40,15/50
GC 0/30
ROTELLA 5/40
AMZOIL 5/30 AME

 

[haley10]

I think CAT recommends -22F for 5W-40's, so that would be my limit on any Xw-40 syn for engines that require a 40wt. I would probably be even more conservative if I were expecting those kind of temps.

 

[Ross]

There has been alot of good press about GC 0w30.

But I get confused cause when you look up the viscosities at cold temps the M1 5w30 is much thinner than GC 0w30, so how can the GC be a "0" weight and M1 be a "5" weight?

I would like to use GC in my 6.0 silverado, but I need a thinner oil this time of the year. So for now I am using 5w30, it's cheap at walmart, and I don't feel bad about dumping it at 3,000 miles

 

[c_rossman]

GC is thicker at 212 degrees but still has cold cranking specs of -35 degrees. Pour point of -78 degrees. I started my truck the otherday when it was -18F with no problems. ON the bottle it says unaided engine starts at -40F

 

[unDummy]

Why would someone in Texas worry about "safe starting temps"?

SAE J300 sums it up for me:
http://www.infineum.com/information/viscosity.html

Anyone with temps too low should consider a garage, an engine oil heater, or a coolant heater. Plug those cars in!

 

[ekpolk]

quote:

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Originally posted by Ross:
There has been alot of good press about GC 0w30.

But I get confused cause when you look up the viscosities at cold temps the M1 5w30 is much thinner than GC 0w30, so how can the GC be a "0" weight and M1 be a "5" weight?
{snip}

---

Because the "w" part of the rating is dependent upon the oil's performance on Cold Cranking Simulator tests, not just "thickness" as is the case with the normal SAE grade. The 0w rating of the "thicker" GC is likely a result of its ability to stay "fully" liquid at lower temps, and not begin its transition to a solid until it's much colder than the "thinner" 5w oils.

 

[Ross]

Thanks Mr. Polk. Looks like GC would be better oil than M1 5W30 at both the High and Low extreme temps.

 

[TomJones76]

quote:

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Originally posted by TEXDOG:
Please weigh in with your opinion on safe starting temps F(cold)for these oils:
ROTELLA 5/40

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According to Shell , the 5/40 product slightly exceeds the 5W spec for pumpability at -31 Fahrenheit / -35 Celsius .
Thus, it'll work adequately down to crankcase and motor oil temps of -31 F. But if your thermometer is reading -31 F, you'll probably want to run 0W-something.
If your thermometer is reading -31 F down there in Texas.... well then, it'll be a cold day in the inferno and the oceans will be turning to yogurt, so I probably wouldn't worry about burning my starter out too much anyhow.

http://www.shell-lubricants.com/products/pdf/RotellaTSynthetic.pdf
http://www.infineum.com/information/viscosity.html

 

[TomJones76]

quote:

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Originally posted by Ross:
Thanks Mr. Polk. Looks like GC would be better oil than M1 5W30 at both the High and Low extreme temps.

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The only criterion the M1 5W30 might win on would be price and availability.

Edit:
The only criterion the M1 5W30 might conclusively win on would be price and availability.

[ December 27, 2004, 03:11 PM: Message edited by: TomJones76 ]

 

[427Z06]

Some info to expand on what ekpolk and TomJones76 mentioned:

Cold Cranking Simulator: The CCS measures an apparent viscosity in the range of 500 to 200,000 cP. Shear rate ranges with engine cranking data at low temperatures. The SAE J300 viscosity classification specifies the low-temperature viscometric performance of motor oils by CCS limits and MRV requirements.

Mini-Rotary Viscometer (ASTM D 4684): The MRV test, which is related to the mechanism of pumpability, is a low shear rate measurement. Slow sample cooling rate is the method's key feature. A sample is pretreated to have a specified thermal history which includes warming, slow cooling, and soaking cycles. The MRV measures an apparent yield stress, which, if greater than a threshold value, indicates a potential air-binding pumping failure problem. Above a certain viscosity (currently defined as 60,000 cP by SAE J 300), the oil may be subject to pumpability failure by a mechanism called "flow limited" behavior. An SAE 10W oil, for example, is required to have a maximum viscosity of 60,000 cP at -30°C with no yield stress. This method also measures an apparent viscosity under shear rates of 1 to 50 s-1

 

[Dr. T]

Correct, GC is slightly 'thicker' than M-1 5-30 at operating temperatures, yet qualifies as being suitable down to -35C whereas the M-1 peters out at -30C due to it's 5W rating...ie. it has a smaller range of 'qualification'.

 

[JohnBrowning]

Out of the oils listed Amsoil 5W30 is your best bet for cold climate use in terms of starting. I would not worry about starting with any of them down to -20F. I would be a little nervious about the Rotella-T 5W40 because I have not tested it in temps. that cold. I can tell you that M1 10W30 and Redline 5W40 work well down to -20F no problem. The M1 10W30 has been tested every year for at least 12 years in these temps in Toyotas.

The M1 15W50 I have never used it in weather below 20F. I normaly change it out when the high temps. drop below 32F just for good measure. My Dad left some 15W50M1 in due to time constraints and when the temp droped to -12F The engine would barley turn over. I made him change it that day. He is an over the road truck driver now that he is retired from the Army and some times he just runs out of time for daily chores. I also see to it that he changes to 10W30 M1 far sooner then he would like!

P.S. In 1993 my Dad and I drove from Georgia to Michigan for me to take a tour of the College Campus. They had a blizzard the day before my tour due to lake effect. My Dad and I were staying with my Grandmother and only arrived 1 day before the orintation tour. We had Castrol GTX 20W50 in the crankcase when we left Ga.! When I went to check the oil the next day the oil had the consistency of molase on the dipstick. I do not remember what the temp. was but I can tell you I heard noises I had never heard come from a Toyota. The warm climate battery in the truck was not happy either. Oh I almost forgot I had 140Wt gear lube in the trans, transfere case and diff's. These also were not happy. I made sure not to drive much while we were their. I changed the oil to 10W30 and parked in side the pole barn!I never dreamed it was that cold their and had thought that my lubes would be fine. Oh how experince is a dear teacher!!!