Cold flow properties

[jayg]

Originally Posted By: Shannow
Originally Posted By: KL31
Or did I use the wrong word "flow" there? Wouldn't the thinner 10W30 be better for cold starts, for example, somewhere where it does not go -0 C?


Yeppers..."flow" is (I believe purposely) misinterpreted depending on context often on BITOG.

-25 to -35C, the edge 5W30 will "flow" better to places like the oil pick-up tube than the 10W30 oil, to be shifted to the galleries and remote places...by "flowing" better to the pick-up at those temperature extremes, its "flow" "protects better".

Think sucking a thickshake up a straw wrt "flow"

Both oils at 0C, there is no problem getting the oil to the pump (thickshake effect), and so from that point onwards, the pump is pushing the same volume per revolution through the galleries, filling that volume at around the same rate.

The "W" ratings are made of two parts:
* the CCS, which is the ability of the engine to turn at a sufficient speed to start
* the MRV, which is the ability of the oil to flow into the pickup tube.

You can get into strange places at temperatures where you and I will never see.

An engine can start, and the MRV be so high that the oil can't reach the pump. One reason is that the MRV is so high that the oil in the pickup tube "separates" and the pump sucks nothing. Other is that the oil can't "fill" the cavity that the suction leaves as the oil tries to cave back into in the sump, and the pump sucks air (air binding).

In either of those places, "cold start" "flow" is important, and prevents engine failure.

In temperatures where neither of these effects exist, i.e. above freezing..."flow" is about the same in all respects.


I guess what I don't understand about some folks obsession with extreme cold weather properties of oil (especially by folks who don't live in them*) is that who are these extreme 0w oils really made for?

* Not you Shannow, you make great points about what is happening internally under extreme cold (-30F and colder)




There's a sweet spot for 0w oils but I don't feel like it's at the bottom of the extreme temperature range. If you're in -15F to + 15F and you are NOT able to have an assisted start by plugging in anywhere, the 0w has the advantage over the 10w in absolute best performance. However, all other systems working fine, the 10w will work and provide protection in adequate time that no life shortening wear will occur.

If you are at temperatures that your oil pump is sucking air because the MRV is so high it can't reach it (Let's say -40F on a 10w)....you aren't starting a motor vehicle with coolant in it because likely your freeze plugs have let go. If your freeze plugs HAVEN'T let go, it's because you have (and it's absolutely necessary not just a convenience) a block heater. BUT, if you have a block heater.....then your oil is going to be sucked through the oil pump because it's warmed, most any oil.

So my deal is just that if you are truly in extreme cold temperatures, you don't just depend on a 0w to start your vehicle. You can't. After you have taken all the other precautions to ensure you are protecting your vehicle (oil pan heater, block heater battery blanket, trans pan heater if you have an automatic) then you can run whatever grade of oil you want in the winter. Literally thousands of vehicles near the Arctic circle that get exposed to these conditions for 4-5 months a year. 30 year old Subarus, Toyotas Fords whatever. Some may be beat to [censored] on the body but still run like a champ and I guarantee you less than 1% of them ran any 0w oil and probably less than 50% even ran synthetic.

 

[kschachn]

Originally Posted By: jayg
If you are at temperatures that your oil pump is sucking air because the MRV is so high it can't reach it....you aren't starting a motor vehicle with coolant in it because likely your freeze plugs have let go. If your freeze plugs HAVEN'T let go, it's because you have (and it's absolutely necessary not just a convenience) a block heater. BUT, if you have a block heater.....then your oil is going to be sucked through the oil pump because it's warmed, most any oil.

So my deal is just that if you are truly in extreme cold temperatures, you don't just depend on a 0w to start your vehicle. You can't. After you have taken all the other precautions to ensure you are protecting your vehicle (oil pan heater, block heater battery blanket, trans pan heater if you have an automatic) then you can run whatever grade of oil you want in the winter.


All my cars and especially the BMW see very low temperatures, often -25F or below. And I assure you the freeze plugs are in no danger of "letting go". I use 0W oils in all of them, are you saying I should use some other grade and install all sorts of heaters just because I don't use a 0W oil?

I mean I'd call this environment "cold", and I do just depend on 0W oils - that and a good battery.

 

[jayg]

Originally Posted By: kschachn


All my cars and especially the BMW see very low temperatures, often -25F or below. And I assure you the freeze plugs are in no danger of "letting go". I use 0W oils in all of them, are you saying I should use some other grade and install all sorts of heaters just because I don't use a 0W oil?

I mean I'd call this environment "cold", and I do just depend on 0W oils - that and a good battery.



That's not what I'm saying at all.

- 25F most times isn't enough to cause your oil pump to be sucking air. -25 (usually) isn't cold enough to lose a freeze plug if your antifreeze % is strong enough. But -40, -50F etc. it gets worse.



I'm just giving numbers for example. Last week I was in Glennallen, AK. it was -41F below by the Copper River where I was. The high was -21F. It stayed below 0F for over a week. I could have run 0w in my truck but because it can be this cold for 4-5 months out of the year, just plugging in, my truck starts great on 10w40 dino. My battery worked well because I have a battery blanket plugged in. Even a BRAND NEW battery when it never warms up won't be happy for long without it.

 

[kschachn]

Well below what I see (like you do in AK) I agree. But for me here in the northern Midwest I think the 0W is quite appropriate.

Many people here do have heaters, and some places have plug-ins for them (besides home of course). But not all places do. The issue for me would come in when I've got my car parked outside for days on end (my daughter at school for example) and there's no practical way to get electricity. In fact, the BMW doesn't even offer a block heater. I just don't see why I would use anything other than a 0W oil, what point would I have in using a 5W?

And I think my situation mirrors a large percentage of people in the northern 1/4 of the county, Alaska can be completely different of course. But what happens when you aren't near a place to plug in all your heaters, or does that never happen in AK?

 

[jayg]

Originally Posted By: kschachn
Well below what I see (like you do in AK) I agree. But for me here in the northern Midwest I think the 0W is quite appropriate.

Many people here do have heaters, and some places have plug-ins for them (besides home of course). But not all places do. The issue for me would come in when I've got my car parked outside for days on end (my daughter at school for example) and there's no practical way to get electricity. In fact, the BMW doesn't even offer a block heater. I just don't see why I would use anything other than a 0W oil, what point would I have in using a 5W?

And I think my situation mirrors a large percentage of people in the northern 1/4 of the county, Alaska can be completely different of course. But what happens when you aren't near a place to plug in all your heaters, or does that never happen in AK?


So in my original post I said there is a sweet spot where 0w is better unassisted. I picked -15 to 15F lows. So lets say it's -25F even on the low end of on that scale. Again, my original post AGREES with you that 0w is better for those kind of temperatures occasionally if you can't plug in. At -25F I certainly would be though. A warmed 10w40 does better than a -25F 0W every single time.

My qualm isn't with those temperatures. My qualm is that everybody talks about extremes. -40F, -50F. More than likely if you experience those temperatures regularly, you are plugging in and my point is if you are already plugging in the you can run whatever.

If you have a 0W oil even with a new battery, it won't be happy long without a heated blanket for 4-5 months. Even with decent antifreeze, I have seen many morning where people that haven't plugged in have popped a freeze plug.


Last winter, in Tok, AK a tourist from Michigan fired up his Honda Element at a roadhouse and I swore to god he was doing a burnout in the parking lot. Screeching rubber and it smelled like it to. I came outside where everybody has plug ins and though he had a block heater he didn't use it. Freeze plug on the parking lot and the sound was from his crank spinning bump his water pump was frozen solid. The belt was doing a burnout on the pulley. This was factory new coolant on a -40F morning.

I helped him call a tow who would put it in a heated garage for 24 hours and hopefully replace the plug and belt so he could keep on.

My 30 year old Land Cruiser with conventional 10W40 and plugged in? Cranked up first try and I motored on.

 

[jayg]

Originally Posted By: kschachn
But what happens when you aren't near a place to plug in all your heaters, or does that never happen in AK?


If it's cold enough to matter (sustained temperatures below -20F) everywhere has plug ins. If I am in the middle of nowhere off the road system without electricity , I have a separate large battery jump box that is fully charged with an inverter just in case but I've never HAD to use it.

When you say all my heaters, I want to clarify the three heaters (oil pan, block, battery blanket) all connect to one junction and I just have one plug to plug in and not three.

I know that 6 cylinder BMW's of that vintage have block heaters available, if yours in v8 you can still put one in easily. Find out what size freeze plug (50mm probably?) you have and buy a universal one or just an oil pan heater or Frostheater inline radiator hose that is universal.

Perhaps this is your part number. Maybe came factory with an Alaska/Canadian/Norway etc delivered car. All BMWs of your vintage and newer have plugs hanging out of their bumper up here and tucked away in Summer:

 

[slybunda]

does that mean that a positive displacement pump which shifts 1 gallon per minute will move 1 gallon per minute of oil regardless if its 0w-20 or 20w50?

 

[UltrafanUK]

Originally Posted By: slybunda
Thats odd threads on here say that a thinner oil flows faster and in more quantity than a thicker oil. ?


True, but it does not effect the main bearings in the same way as the top end. If you use too thick an oil the flow rate to the top end will slow down more than than the flow to main bearings in most types of engine (Depends on oil gallery size).
Every bearing has specific design spec's for both minimum viscosity AND flow rate.

Oddly enough you only get significant extra cold start wear if you start an engine when the oil is colder than 10c above pour point. That seems to be the temp at which the slow oil flow starts to cause real trouble.
The advertising folks try and imply that an 0wX is better for any cold day, which is just not true in wear terms, BUT is true in terms of battery and alternator loads.

 

[kschachn]

Nah, it's an M60 and from all I've seen there never was a factory block heater available for that engine. But really it doesn't matter since for that car in particular there aren't meaningful opportunities to connect to electricity. The BMW does have one advantage in that the battery is underneath the rear seat and you do get a bit of greenhouse heating if the sun is out.

And that Honda had improperly mixed coolant if it froze above the specification. For Honda Type 2 in very cold climates you are supposed to add the undiluted "supplement" Type 2. Chemistry is chemistry, if the coolant is the proper concentration it won't freeze.

 

[crazyoildude]

Did you see a current PDS for that oil?? The last one i saw was all the way back in 2014 unless i missed something....However PQIA showed one this year but it was the 5w20 yellow bottle nothing special but ok just the same however i did not stand out from the rest...

 

[Garak]

Originally Posted By: KL31
So due to chemical makeup of a particular oil it can be thicker in all regards but have a better cold crank than an oil that is thinner in viscosity?

Sure. In brutal winter conditions (i.e. -30 C), I'd rather have a 0w-40 or a 5w-50 than an SAE 30. And Solarent's remarks on pour point are worth reading again. Royal Purple's 15w-40 had an impressive pour point of -45 C or -48 C or something like that. Given the 15w-XX number, I wouldn't be using it in -45, though.

As for the mention of 5w-XX and 0w-XX usage in general, even in places that don't need it, that's simply been the trend for a lot of years. The best fuel economy oils tend to have a lower HTHS and higher VI, and regardless of the country of origin, whether it's an A3/B4 or simply an ILSAC lube, the end result has often been a 0w-XX or 5w-XX oil. Look not only at what a Toyota specifies, for instance, but even some of the diesel approval lists and the European OEM lists.

 

[slybunda]

what determines flow to the top end is it the 100c viscosity or the hths?

 

[supton]

I had a thought, and perhaps it deserves its own thread. Maybe it should split off, if that is the case.

Re: cold flow. Usually we think of getting oil to bearings. However, most engines lubricate cylinder walls from the spray generated by oil "leaking" (for lack of a better term) out the clearances between rod(s) and crank throws. Whether that oil is flung due to pressure or centrifugal force I'm not sure; but I believe that is how most of the cylinder walls get their oil.

Under cold conditions, how is that impacted? I know "gobs" of oil is not required here. So I guess the question goes from, instead of "cold flow" is oil "spray" impacted in the cold? I'm guessing it's just not an issue, otherwise we'd be discussing that instead.

[I'm not sure how old school cam-in-block V motors oiled the camshafts; I know the bearings had oil, and there were openings above the camshaft; but I wouldn't be surprised if they too were oiled by crankshaft spray.]

 

[Shannow]

supton, specially for you....

Bear in mind that they state that their tests were with "one of the best", and "one of the worst" off the shelf oils in each grade.

And that this was a previous definition of the "W" rating, so it's not the familiar CCS and MRV.

Basically, the lower "W" rating just moves everything down the temperature curve.

I've never found (nor do I think I will) something that shows this data at 100F, at which is is often claimed that "of course a 0W is better at 100F too", as clearly, when the oil is pumpable, galleries fill at the same time, in everything I've found...no point testing the obvious.

In the test engine, on a pumpable oil, the mechanical filling times seem to be 1 sec for oil pressure, 3-5 for last cam lobe, and 5 sec for last cylinder.

 

[Shannow]

Supporting my above statements, here's another curve from the testing. (And and B are the same 10W30s as the last few, C and D the 5W30s)...note the flat bottom to the curves, once the oil is pumpable, it gets there the same...and at higher temperatures it would still be flat.

In deference to those who accuse me of cherrypicking, there's another curve that paints a much less clear picture. It's a different engine design to the other (the 2.3 is a Ford, and the 2.2 is a Chrysler).

Personally, with it not displaying the "normal" behaviours, on either grade, I would say that it's a poorly designed engine, with too narrow oil galleries such that viscous drag occurs, delaying filling times regardless of "W" rating.

100 seconds to get to the most remote cam bearing at 0C, on either a 10W OR a 5W tells us a couple of things
* poor design
* A second or two difference means nothing
* The Chrysler 2.2 apparently survived sufficiently long as a commercial product that minutes to get the cam oiled didn't detract from it's service life.

(A cynic might say that this was precisely the reason that Esso chose the engine for their cold start videos)

https://bobistheoilguy.com/forums/ubbthreads.php/topics/3839413/The_Esso_cold_weather_oil_vide

 

[supton]

Originally Posted By: Shannow
supton, specially for you....

Bear in mind that they state that their tests were with "one of the best", and "one of the worst" off the shelf oils in each grade.

And that this was a previous definition of the "W" rating, so it's not the familiar CCS and MRV.

Basically, the lower "W" rating just moves everything down the temperature curve.

I've never found (nor do I think I will) something that shows this data at 100F, at which is is often claimed that "of course a 0W is better at 100F too", as clearly, when the oil is pumpable, galleries fill at the same time, in everything I've found...no point testing the obvious.

In the test engine, on a pumpable oil, the mechanical filling times seem to be 1 sec for oil pressure, 3-5 for last cam lobe, and 5 sec for last cylinder.


Finally got around to looking at the pics (stupid work filters). Interesting video, but I don't think it addressed my question about cold fling only cold flow. I think oil won't fling (or spray) as well when cold. Not like when hot and thin. I wonder if that is the case in that first picture, where "last cylinder wall oiling time" takes longer and longer to get properly oiled, despite oil being used within spec. It's not being oiled (directly) by pressure, but rather what is flung out of the rod bearing side clearance.

Maybe it's a meaningless distinction, and more related than I'm thinking (viscosity being in play in both roles).

[Regardless, I don't stay awake wondering about such things! Nor do I plan to worry about cold "fling" since engines clearly work fine.]