Real life cold flow issues

[FowVay]

This morning it was very cold here in the 'burbs of Atlanta. The local airport reported 17º F which is very cold for our climate. In the name of science,, and because I'm a freakin' idiot, I pulled my old junker VW Rabbit into the garage after it sat outside all night and I got a clean drain pan and commenced to draining the 15W-40 Quaker State HDX that I put in during November. Let me tell you that even at a warm 17ºF this oil barely poured out of the sump. I removed the drain plug and the oil didn't even get on my fingers because it was so slow to pour.

I was shocked to say the least. This did NOT reflect any of the indications that I've gotten from the freezer tests nor does it resemble the -20ºF pour point that the oil is supposed to have.

Even in my old beater I'm going to stick with 5W's in the winter time and reserve the 15W's for spring/summer use.

 

[FowVay]

geeeman,, I certainly hope that I never have to find out how my 15W-40 does in those temperatures. I've gotten soft over the years and now I know why people retire to Florida.

Jetforeman, I poured 5W-40 into my car this morn to replace the 15W-40 just to see if it makes a difference throughout the week.

Do you work at the big D by any chance?

 

[Dr. T]

You just witnessed a 15W which should work down to about -15 to -20 C (5 to -4F). So you still had some leaway.

As a side note: You just broke a Cardinal rule: NEVER drain the oil cold! For just that reason....you probably left half of it in the engine and pan because it was so cold.

This is why the whole whoopla about cold flow is a crock of s**t. The engine is coated in oil and when you start the car, the oil's already there....even more so with the thicker viscosity...ie. the water thin one is sitting in the oil pan because it ALL drained down and now needs to be pumped up...whereas the thicker visc. is already where it's supposed to be....on the parts ready to lubricate! (this is assuming you're above the oil's borderline pumping temp of course)

 

[Spector]

Sort of disagreee. When the engine is warm, even in zero degree weather, it will take 15-30 minutes to come down in temp to the outside air temp, even longer I feel. Thus the oil, regardless of weight, will have drained to the sump by the morning.

 

[FowVay]

I agree with Spectre, when the engine is shut off the oil temps are in the 200ºF range which allows nearly any viscosity motor oil to drain to the sump in a rather quick manner.

As for breaking the cardinal sin of a cold drain,,, I just did it for curiosity. Actually I let it drain for over two hours and I refilled with four quarts to replace the four that drained out.

It is simply amazing how much easier the engine cranked with warmer and thinner 5W-40. Only problem is that now I have a pan of low mileage 15W-40 that I need to store until the spring thaw.

 

[Patman]

quote:

---

Originally posted by FowVay:


It is simply amazing how much easier the engine cranked with warmer and thinner 5W-40. Only problem is that now I have a pan of low mileage 15W-40 that I need to store until the spring thaw.

---

Why bother saving it? It's not expensive oil and it's probably already contaminated with dirt and stuff. (especially if you didn't use a brand new catch pan)

 

[DockHoliday]

quote:

---

Originally posted by Dr. T:
You just witnessed a 15W which should work down to about -15 to -20 C (5 to -4F). So you still had some leaway.

As a side note: You just broke a Cardinal rule: NEVER drain the oil cold! For just that reason....you probably left half of it in the engine and pan because it was so cold.

This is why the whole whoopla about cold flow is a crock of s**t. The engine is coated in oil and when you start the car, the oil's already there....even more so with the thicker viscosity...ie. the water thin one is sitting in the oil pan because it ALL drained down and now needs to be pumped up...whereas the thicker visc. is already where it's supposed to be....on the parts ready to lubricate! (this is assuming you're above the oil's borderline pumping temp of course)

---

I am thinking that if the oil is that thick, it would not do the rings any good - it will simply get scraped out of the way and stay there.

IMHO, he did the right thing by draining the thick oil out when cold. Also, since he was changing the oil for viscosity reasons, not the age/contamination, a small amount of old oil should not be a problem.

[ January 07, 2004, 04:43 PM: Message edited by: DockHoliday ]

 

[FowVay]

Patman, this oil was bought from the clearance rack at wally world for a whopping $2.00 per gallon. It isn't cost effective to save it but I have troubles parting with it. I have a special drain pan that I keep for these moments when my enquiring mind just has to known....

 

[Dr. T]

I'm just speaking from experience...this year with the 10-60, it's very difficult to check the oil cold (below 30F) as it's clung all along the entire length of the dipstick...indicating to me that not all of the oil is draining into the pan. Checking it hot is the only accurate method.

Don't know about you guys, but yesterday it was
-10C and I returned to the car after 15 min. and the temp. needle was already down halway between cold and normal temp....so things cool quick in extreme cold...

 

[DEWFPO]

I think the pour points on these oils change after they have been altered chemically in the engine for a while. It would be interesting to compare pour points of used oil vs. new oil.

DEWFPO

 

[TooSlick]

According to the SAE, the definition of "borderline pumping temp" or "BPT" is when the oil has thickened to 60,000 Centipoise, regardless of it's initial viscosity. Just try starting your engine with 60,000 Cp oil in the crankcase - it's like honey in your frig. Oil that this viscous is going to cavitate when you try to pump it.

To be conservative, I'd use the standard CCS test temps as the practical low temp limit for a given SAE grade - that's the reason they exist:

20w ...+5F/-15C
15w ...-4F/-20C
10w ...-13F/-25C
5w.....-22F/-30C
0w.....-31F/-35C

These CCS viscosities will vary widely from 3000 Cp for some PAO based synthetics, to 6500 Cp for cheap, off brand petroleum oils. So you should look at the actual CCS viscosity and not just the SAE grade ....

 

[JohnBrowning]

4 Degrees this morning here in Michigan. I run Redline 5W40 in one car and 10W30 Castrol Syntec-Blend in the other car. Both are kept outside and both start just fine. Until it hits -15 or colder and that is not with wind chill then you really do not see a lot of cold start issues. THe possable expection would be if the oil being used is way to thick for temps.

 

[JohnnyG]

I have a pour point/cloud point tester at work that goes down to -40 deg F. I can tell you that the definition of pour point is something like "no visible distortion of the surface contour...." it goes something like that. I don't do a test for pour point, but I do test for "cloud point". Now for the "point" of my story, we test diesel fuel! In other words, if -40F or less(warmer)will make diesel fuel a SOLID, what chance do you think motor oil has? I HAVE frozen diesel fuel with this setup. One important factor to consider though, we run the fuel sample through a special "phase seperation" filter to exclude water from the sample. Water would skew the cloud point test by "clouding" up at 32 deg. I cannot run motor oil through this type filter, it would take over 12 hrs. to get a couple of ounces through it! You guys name the temp and define the test and I will post pictures of the results of some suggested oils. Or I'll send them to somebody that has a place to post pictures. The test vial is a clear glass cylinder about 1" in diameter and about 3" long.

 

[RichR]

JetForeman,
Check your PM's
Thanks!

 

[greencrew]

If it's cold enough and you park your car facing into the wind the engine will cool before all the oil drains back into the oil pan. It's an old Minnesota trick when the temp drops to -30*F to park your car out of the wind to allow the oil to drain off before the engine cools. Otherwise it takes more battery amps to turn it over with the engine coated with thick oil. For some engines it will make the difference between starting and not starting.

Funny how after a long cold spell it's nice when things warm up to 17*.

 

[JetForeman]

I too am freezing to death is this cold Atlanta/Artic air. Who ta heck turned the heat off??? And to think when I moved here 17 years ago I thought it was going to be warm year round, boy was I ever wrong.......

To get back to your post have you considered using a 5W-40? I'm thinking about using it in my new Nissan Titan once I get a few thousand miles on it.

 

[geeeman]

You guys are wimps...!

In Calgary , Canada, we had a low of -26c (-15f)
and it's WARMING up! Been as low as -33C (-27f).

I wonder what that 15W40 would be like in these temps...?

 

[Dan4510]

Maybe if this global warming takes off, we wont have to worry about these low temps and can all go back to cheap dino oil!

NAH!

Dan