Whats too cold for 15w-40?

[JohnBrowning]

When I said 10F that is the limit not what I would recomend!! I thought I should make that clear! I really like 15W40 HDEO!! When the highs start to be lower then 50-32F I start thinking about changeing. Once I hit 20F I would not consider any 15W oil at all even synthetics. I run my oil at least 6 months and once the temps start droping off -18 is not far away.

For winter Syntetic 0W30,3W30,5W30,5W40,10W30 are my choices. Once lows warm up to 32F I start considering 15W50,15W40,10W60 etc......... It is always best to play it safe dureing cold winter starts.

If you south of the mason dixie line run what ever you like because it will never get cold enough to cause any problems!

 

[steiner43511]

schaeffers 15w-40 has just as good of a cold flow as rotella 5w-40. im not to worried even in northern ohio. it has already been down below zero once or twice during the night.

 

[Quick_lude]

quote:

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Originally posted by wwillson:

quote:

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Originally posted by Strjock81:
I see Rotella 15w-40 posts a pour point of -36. This about 10 degrees higher than the Delvac I am currently running. What does pour point really mean?

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In the real world - not much. The Cold Cranking Simulator Apparent Viscosity is what you're interested in...

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Ditto, while a low pour point is nice, what you really need during those colder start up days is pumpability to get the oil flowing. What is the defiinition of "pour" anyway? A 15w40 might pour like honey in -10F but it will still pour right? You wouldn't want that in your engine though. Personally I'm using the Esso XD-3 0w30, we hit a few spells of -25 C this week and the truck started without any issues, no block heater either, no plug at work

 

[heyjay]

My Cat engines had the following low temp cutoff points for the following viscosities:

15W-40: -9.5 C / +15 F
10W-30: -18 C / 0 F
5W-40: -30 C / -22 F
0W-30: -40

Note the 5W-40 and 0W-30 oils are synthetic. These recommendations are very conservative and apply to HD diesel motors. I think they're prudent.

You can actually do more engine damage by using an oil too thick for cold temps, than using an oil "too thin" for hot temps. The engine damage from using an oil too thick for cold temps is usually immediate and catastrophic.

 

[brianl703]

quote:

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Originally posted by JohnBrowning:
If you south of the mason dixie line run what ever you like because it will never get cold enough to cause any problems!

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Monday's low was 10F here in Manassas, VA.

 

[427Z06]

15w SAE rated oils are technically good to -4F. Add 10F to that for a little insurance and that gives you 6F. However, 15w40 HDEOs are for the most part dinos (exceptions noted) and will be pretty thick through the single digits and teens temps, so you probably don't want to start and run your car engine everyday at these temps with 15w40 dinos unless you have some auxillary heating. But for the rare 1-2 day cold snap in unusual places like Texas, I'd say you won't do any significant harm with a couple of mid-single digit starts if your engine is in good shape.

 

[Terry]

427 be careful using crank temp standards as thicker oils can crank OK and then refuse to pump properly unless much warmer. I have seen oils get gelatinous and not pump at all, sucking air, no oil.

The CAT spec listed above compensates for that with the 15w-40's.

A good full syn 15w-40 like Amsoil AME is excellent at cold weather ops.

Schaeffers 15w-40 blend is good too but be careful if using in a smaller gas engine for the pump after cranking if temps are single digit F.

 

[427Z06]

Terry, Hmmm...so should the SAE J300 standards be ignored? I thought (and read) that's why they chose the CCS and MRV viscositys and temperatures. I.e., if the the engine simulator will crank, the oil will flow since the MRV test ASTM D 4684 is at a 5C lower temperature and specifies that the presence of any yield stress detectable by this method constitutes a failure regardless of viscosity?

 

[Terry]

True 427, but the Gelation index cannot be ovelooked.D5133.

Guys are running 15w-40 dino HDD oils in all kinds of differing engines and could get their oil pump's panties in a bind in a cold snap like we are having now. Most new oils crank well due to the starters and batteries being good quality.

 

[Last_Z]

quote:

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Originally posted by Terry:
True 427, but the Gelation index cannot be ovelooked.D5133.

Guys are running 15w-40 dino HDD oils in all kinds of differing engines and could get their oil pump's panties in a bind in a cold snap like we are having now. Most new oils crank well due to the starters and batteries being good quality.

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Not that I know much about the subject.....just wanted to add to Terry's very last sentence. I read somewhere that the ability of new car starters has surpassed that of oil in very cold weather. In other words, manufactures are scared that the starter will crank and start the engine while the oil is solid. So as Terry implied, just because it starts and runs, doesn't mean the oil is flowing good.

 

[427Z06]

Terry, can you have a "high?" gelation index and still have no detectable yield stress under ASTM D 4684? And if you can have the oil gel, but not show any detectable yield stress under ASTM D 4684, what the heck good is the J300 chart? I.e., you could meet 5w specs but if it gelled severly, the 5w grade rating would be meaningless?

Last_Z, I'm aware that car manufacurers were concerned that with modern FI, the ECMs would rev the engines to a prescribed RPM, versus the old days when the RPMs would depend on frictional losses and throttle settings. That is why SAE modified the J300 viscosity grade chart in 1998 or there abouts. Haven't read about starters being any more capable today than they were 15 years ago. Maybe smaller and more efficient, but I doubt more powerful, but if you have a link, send it to me, I'd like to read it.

 

[427Z06]

For those learning along with me:


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.

ASTM D 5133, the Scanning Brookfield technique, measures the Brookfield viscosity of a sample as it is cooled at a constant rate of 1°C/hour. Like the MRV, ASTM D 5133 is intended to relate to an oil's pumpability at low temperatures. The test reports the gelation point, defined as the temperature at which the sample reaches 30,000 cP. The gelation index is also reported, and is defined as the largest rate of change of viscosity increase from -5°C to the lowest test temperature. This method is finding application in engine oils, and is required by ILSAC GF-2.


Reference, Lubrizol website:

http://www.lubrizol.com/ReadyReference/LubricantBasics/viscosity.asp

Seems to me if you add 5C to the ASTM D 4684 test temperature which defines a max of 600 P, you'd be darn close to the ASTM D 5133 temperature at which you reach 300 P. (10F ~= 5.5C, reread my original post)

[ December 23, 2004, 05:26 PM: Message edited by: 427Z06 ]

 

[Terry]

427, no, normally, no. If it pumps well then gelling is not NORMALLY a issue.

It may crank easily because of other issues and then suck air instead of oil.

The crank vis is the issue not the pump. I pretty much ignore the crank vis and focus on pump for cold weather ops.

Gelling in a lube is more of a slow cooling issue and the propensity for the oil pickup to pull air from a hole in the surface of the oil.

Gel scale D5133

>6 and some gelling tendencies exist.

>12 US automakers don't want the oil used

>15 oils that fail .

 

[Last_Z]

427,

You are correct! The combo of strong batteries, starters and FI/ECM is what I was referring to.
My wife's Corolla starts and immmediately goes to ~2k RPMs, regardless of weather. That can't be good!

 

[427Z06]

Anywho, here's the method I was using to determine cold temperature cut off, YMMV.

SAE Viscosity Grade 15W-xx per SAE J300

MRV (Pumping) 600 P max at -25C (-13F)
CCS (Cranking) 70 P max at -20C (-4F)

Add 10F (5.5C) to CCS temperature for safety factor = 6F (i.e., don't attempt to start below this temperature. Heat the oil or change it out.)

But if your owners manual specifies different values, by all means use that as a guideline.

 

[heyjay]

It makes no sense whatsoever to push an oil to the very edge of its gelation point, let alone the MRV 600P limit.

When you examine the recommended viscosity charts from engine OEM's like Cummins and Cat, they tend to err on the side of extreme caution. Considering their motors cost +$15,000, that only makes sense.

I've always run a very thin oil, like a synthetic 0W-30 (And now Mobil 1 0W-20, works GREAT) in cold temps, especially -25 F and colder. The motor is much easier to start without any nasty noises.

To be sure, you may cause more long-term engine wear (Though doubtful any immediate failure) from using a much too thin oil in very hot ambient. Though maybe not, the UOA from folks running Mobil 1 0W-20 and towing makes me wonder.

However, I have witnessed and know very well you can cause immediate and catastrophic engine damage running too thick an oil in very low temps.

A little common sense goes a long way here.

 

[Pablo]

heyjay - I agree, no need to push it, that's for sure....the butt cold places of the world are fairly predictable. Drop a winter oil in mid fall or so and change out after winter....mileage and abuse depending of course.

 

[427Z06]

quote:

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Originally posted by heyjay:
It makes no sense whatsoever to push an oil to the very edge of its gelation point, let alone the MRV 600P limit.

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At 10C (18F) above the MRV limit, I hardly say that's pushing it.

Go back and read my original post. I didn't recommend it as the best way to go on a regular basis. I said that a couple of starts 10C above the MRV limit probably won't harm your engine. If serious harm was being done, I'm sure you would notice the noise in addition to the oil pressure gauge/low oil pressure light.

Growing up in Buffalo, I've seen plenty of sub-zero weather too. You're not the only one with cold weather experience.

[ December 23, 2004, 10:51 PM: Message edited by: 427Z06 ]

 

[Stinky Peterson]

Here is what Caterpillar recommends for off road equipment:

0w20 -40F to 50F
0w30 -40F to 86F
0w40 -40F to 104F

5w30 -22F to 86F
5w40 -22F to 122F

10w30 0F to 104
10w40 0F to 122
15w40 0F to 122

 

[srivett]

Are you talking new oil or used oil?

I don't have the experience you guys have as I'm a new diesel owner but it appears to me that old oil is really thick when cold. I found this out when pouring all of my used oil containers into pails.

My brothers 89 VW 1.6 with cheap 10w30 diesel oil seems to start just as well as my 92 VW 1.6 with Rotella 0w40 when it is -25C. Ofcourse he has way more compression which must help. Neither of us NEED to plug in at this point but for longevity...

Cheers, Steve