Synthetic cold flow vs conventional

[actionstan]

Hello All,

I feel like this is one topic that is often overlooked when we discuss wither synthetic vs conventional may fit someones application better. I feel like we are typically looking mainly at the "oil change interval" and performance of the application i.e. Turbo/d.i./Super charged.

Sure.. if you are dead set on going with 3000 miles between oil changes a "full synthetic" is likely not needed, and definitely NOT cost effective. I however have been using and will continue to use synthetic in our '13 Forte for manufacture recommended OCI's (7500 miles).

Why? well.. a large part of it is cold flow characteristics. Sure I don't live in an overly cold climate but in the winter.. it can get kinda low.. I sleep better knowing that when my Wife(primary driver of the car) buzzes off at 6:00am in the morning on a cold winter day.. that hopefully the oil will do just a little better.(I also feel that 7500 is kind of a long OCI for a conventional without UOA's, but more than likely they are up to the task. Overall it plain and simple makes me sleep better!)

I feel this way because I see Pennzoil doing these cold flow test in videos, and the difference is phenomenal.. Is this all marketing hype? This theoretically comes into play regardless of the temp outside. Do you feel that the cold flow advantage synthetic offers is is not really applicable unless you have extreme cold, or consistent cold? Or do the anti-wear additives in modern motor oil make cold flow characteristics non-competitive?

I guess I am challenging the thought that "synthetic is only needed/good for extending drain intervals, let me know your thoughts Bitog.

 

[EdwardC]

I don't think anyone is saying that synthetics are only good for extended OCIs. I think the benefits of synthetic oils for cold temperatures is often cited. Both for easier starting, and faster oil flow/less wear.

 

[webfors]

Extended intervals, cold flow properties, and cleaner engines. Those are the benefits propagated on this board over the years.

 

[Shannow]

Oil near it's gel point, and being poured from a bottle under gravity is not in any way representative of how it will "flow" in an engine under the action of a positive displacement pump.

Closest such a test comes to being representative of something pertinent to your engine is changing the oil in freezing conditions as it runs from the bottle through the fill hole.

A grossly misapplied oil will have trouble feeding the pickup screen, but any reasonable oil choice will "flow" fine under the action of the oil pump

 

[ZeeOSix]

Originally Posted By: Shannow
Oil near it's gel point, and being poured from a bottle under gravity is not in any way representative of how it will "flow" in an engine under the action of a positive displacement pump.

Closest such a test comes to being representative of something pertinent to your engine is changing the oil in freezing conditions as it runs from the bottle through the fill hole.

A grossly misapplied oil will have trouble feeding the pickup screen, but any reasonable oil choice will "flow" fine under the action of the oil pump


Except if the oil is super thick, it will cause the oil pump to go right into pressure relief even at an idle, and the pump will just pump most of the oil volume back to the oil pan. The oil volume going through the engine in this scenario is basically how much will flow when forced at the max pump pressure as controlled by the pump's pressure relief valve.

A full synthetic will allow more flow volume at pump max pressure (when the pump is in pressure relief) than a very thick oil will - so there still is an advantage to full synthetic flow-ability in extremely cold climates.

 

[nobb]

Doesn't the X in the XW30 rating refer to the viscosity at -25C? Therefore, at -25C, should a synthetic 5W30 not pour roughly the same as a conventional 5W30?

I too am confused about the claims that synthetic have better cold pour characteristics. You see many Youtube videos comparing pouring a synthetic vs conventional oil, but it's not usually the same grade. eg. they will pour a 5W30 synthetic and compare it to a 10W30 conventional. Obviously not a fair comparison.

 

[fdcg27]

Some syns have notably good cold specs.
Not all do.
You do make a valid point.
However, many of us ran dino 10W-40s through Ohio winters that were sometimes just as cold as the last one without issue.
Would a syn with good cold numbers be desirable?
Sure.
Will the engine die an early death wthout it?
No!

 

[Shannow]

Zee0Six ... Reread what I said about misapplied oils.

Of course q synthetic of a different grade wull be dufferent ti a "thick" oil

a synthetic 5w30 is going to have essentially zero difference in "floe" in the OPs case.

 

[NewYorkBuck]

I just said something similar on another thread - for basically an extra few bucks per oil change (less than ten and probably closer to five), you get all of the benefits of a syth over a dino. Yeah, yeah, you may never need the extra benefits of a synth. Sure, but what to consider is how much extra it will cost you over that trivial amount in the perhaps not-so-unlikely event that you do.....

 

[KrisZ]

Originally Posted By: NewYorkBuck
I just said something similar on another thread - for basically an extra few bucks per oil change (less than ten and probably closer to five), you get all of the benefits of a syth over a dino. Yeah, yeah, you may never need the extra benefits of a synth. Sure, but what to consider is how much extra it will cost you over that trivial amount in the perhaps not-so-unlikely event that you do.....


And can you point us to the "not-so-unlikely" event, tell us what it might be and present us with some documented cases of it happening? And then please show us some documented cases where a synthetic oil prevented such an event?

A bunch of feel good rhetorics does not facts make.

 

[NO2]

A 'not so unlikely event'

In extremely cold weather - weather so cold your car never warms up and you are constantly scraping the frost from inside of your windshield- your battery can only deliver a small fraction of its current. US Spec cars don't usually include a block heater. Synthetic oil helped me start my car in -30C to -40C Ottawa winters even after leaving it outside overnight. At those temperatures, having a working vehicle is critical and the better flow characteristics of many synthetics are a safety rather than convenience issue.

For Ohio I doubt it would make a difference more that a few days in a century. For states and provinces above the 45th parallel having a working vehicle regardless of outside temperature is essential.

 

[demarpaint]

I have a Pre-Luber installed on my van. As soon as the temps reach the mid to upper 30's I can tell the difference between dino and synthetic oil. The Pre-Luber is an electric oil pump which I control with a toggle switch, it is primarily used to prevent dry starts in my van.

When the temps dip to the above numbers synthetic oil builds pressure faster than dino oil. So much so that with this Pre-Luber you can measure the difference it takes to build oil pressure in seconds. Does this equate to a difference in the real world, when oil is being pumped through the oil pump on a cold start? Maybe, maybe not, but it helped further sell me on the use of synthetic oil, especially in colder climates.

 

[pbm]

I believe that the cold flow differences between synthetic and dino (of the same grade of course) are less now than when syns were PAO. Having said that, I still feel better with a synthetic on the coldest mornings. (0*F is about the coldest it gets where I live and in the teens are more likely).

 

[zuluplus30]

It doesn't get cold enough in Ohio for this to be an issue. Ever. Your body might hate a 0 degree morning cold start but a conventional 5w-30 won't care.

 

[wymi516]

So which conventional oils 5w-20's and 5w-30's have the best cold flow specs?

 

[jmb3675]

Originally Posted By: wymi516
So which conventional oils 5w-20's and 5w-30's have the best cold flow specs?


I would like to know too. Is there a good way to tell looking at a spec sheet?

 

[Stelth]

OK, here's a question. Looking at the PQIA website, I see that Castrol Edge 5w-30 shows 5544 mpa s at -30 C. Citgo Supergard conventional 5w-30 shows 5526. Does the Castrol flow better at -30? If so, why?

OTOH, Mobil 1 5w-30 shows 3937 mpa s at -30 C. Doesn't that mean that Mobil 1 will flow quite a bit easier at this temp than the above mentioned two?

Petro Canada 5w-30 conventional shows 4583 mpa s at -30 C. Wouldn't this indicate better cold-weather performance than, say, Cam2 Synavex at 5624, Mobil Super Synthetic at 5436, Royal Purple at 5562, and Lubrigold at 5453? I'm only looking at SN, GF-5 5w-30's here.

 

[Garak]

The Petro-Canada conventionals do have some good winter performance, and they do advertise that. On the other hand, their synthetics aren't the absolute greatest in the winter (at least with normal SN/GF-5 5w-30), but still certainly more than acceptable. I think one would be hard pressed to notice major differences between any SN/GF-5 5w-30s in even the coldest temperatures. The data is there and can be perused, but all things being equal, I worry about my battery first when it's that cold.

 

[ZeeOSix]

Originally Posted By: jmb3675
Originally Posted By: wymi516
So which conventional oils 5w-20's and 5w-30's have the best cold flow specs?


I would like to know too. Is there a good way to tell looking at a spec sheet?


Look at the Pour Point. For example, the conventional Mobil Super 5000 has a pour point of -36°C (-33°F).

http://www.mobil.us/USA-English-LCW/carengineoils_products_mobil-super-5w30.aspx#

Link: Pour Point

The pour point of Mobil 1 full synthetic 5W-30 is -42 ºC. So even though it's the same viscosity rating as the Mobil Super 5W-30, it has a lower pour point which means it's a little more viscous at cold temperatures.

 

[Greasymechtech]

It makes a difference. Continue using a synth. And, don't forget about the 0w30 oils. It also dosent need to be extremely cold to benefit.

Vehicle soundproofing prevents most owners from having a clue on what noises are going on under the hood.

Oil still needs to reach the pumps pickup. Air doesn't lube all that well.

There is more to an oil than a single temp measurement point.