0w-40 observations in a 5w-30 recom'd vehicle...

[Clevy]

I went from a 20 grade to a 40 grade in my charger. When cold there was a definite difference in how the engine performed. There was more drag,I could feel it,but once the oil was at operating temp there was little to no difference.
But that's going 2 grades thicker.
Going a single grade thicker would be very hard to notice any difference once the oil was in service.
It's possible that the old oil had sheared enough that when the thicker oil was put in the engine felt a bit sluggish til hot but I seriously doubt that comparing an engines responsiveness with 2 oils being only a grade apart that a person could notice any difference.
But at the end of an interval using a 30 grade it's certainly possible that the oil sheared to nearly a 20 grade,so in reality it's comparing a 20 grade to a 40 grade which I then can certainly believe the change is perceptible.
I can certainly tell in my hemi's,every mod motor I put a 40 grade in was sluggish for the first 1000 miles,and last summer I tried out a 5w-20 in a very high mile 302 and the difference was absolutely perceptible. The engine definitely had more pep when light throttle inputs were used.
Not that I believe there is any real difference at wide open throttle however when driving light footed.

 

[wemay]

Although my oil never smells of fuel, that may be as plausible a rsason as any.

 

[Mr_Incredible]

I've run different weights in the truck and the difference between 30w and 40w was obvious to me. It sounded and felt like it was full of molasses with M1 TSUV 5w-40.

I used thin 20w, 30w, thick 30w, and 40w...all the UOAs came back simimilar. Nothing special either way.

 

[CATERHAM]

Whether one can notice the difference running a heavier than necessary oil makes that really shouldn't be the reason to do so.
At the back of many members minds, mostly newbies (and of course the hopeless belt and suspenders thicker is better set) it's a myth that there is greater high temp' protection in running a heavier grade especially if it's mentioned as an option by the manufacturer.
The fact of the matter is, there is no lubrication advantage to running the heavier oil (and if you read carefully what the OEMs recommend they all confirm it) but there are lots of reasons not to.

 

[Whimsey]

Only time I really varied in viscosity is in my pre BITOG days when I went from the recommended 5W-30 to 5W-50 synthetic for my 1996 Zetec Contour. I thought "thickerer is betterer", wrong. It was really sluggish and the mpg took a huge hit. Went back to synthetic 5W-30 after ~2 years and all has been better. I'm back to 26-28 mpg local and 33-36 highway, just my observation. I know this is not a 40 weight story but I'd thought I give my

.

Whimsey

 

[Jaymus]

Oddly, my truck revved better and felt better going UP TO Rotella T6 5W-40 vs the Castrol GTX 10W-40/10W-30/5W-30 I had tried prior. Maybe it was helping compression lol.

On the other hand, the GTX 10W-40 was noticeably more sluggish than 5W/10W-30.

 

[wemay]

Originally Posted By: CATERHAM
Whether one can notice the difference running a heavier than necessary oil makes that really shouldn't be the reason to do so.
At the back of many members minds, mostly newbies (and of course the hopeless belt and suspenders thicker is better set) it's a myth that there is greater high temp' protection in running a heavier grade especially if it's mentioned as an option by the manufacturer.
The fact of the matter is, there is no lubrication advantage to running the heavier oil (and if you read carefully what the OEMs recommend they all confirm it) but there are lots of reasons not to.



Hence, why I will go back to SYNpower 5w30 after this try. Sound TEOST scores, good uoa's and I dont need anything to last beyond 5K mile oci. This is what I get for having ants in pants, always lookong for something 'better'.

 

[wemay]

...or Royal Purple,

 

[FetchFar]

Originally Posted By: wemay
...or Royal Purple,

.. I can't get over the use of purple dye in their oil. Anyway, its probably OK oil. Certainly its right to look for the best oil in your app, keep looking, given sketchy consumer evidence out there, not easy.

 

[wemay]

Originally Posted By: FetchFar
Originally Posted By: wemay
...or Royal Purple,

.. I can't get over the use of purple dye in their oil. Anyway, its probably OK oil. Certainly its right to look for the best oil in your app, keep looking, given sketchy consumer evidence out there, not easy.


Thanks FetchFar

 

[Garak]

Originally Posted By: FetchFar
I can't get over the use of purple dye in their oil.

Most oils are dyed. What makes purple any less valid a choice?

 

[wemay]

Originally Posted By: Garak
Originally Posted By: FetchFar
I can't get over the use of purple dye in their oil.

Most oils are dyed. What makes purple any less valid a choice?


Really? I didn't know this. Maybe it makes people uncomfortable to see purple rather than the commonly seen shades of amber. It can also be chalked up to all our irrational dislikes. Mine is QS having Jef Gordon on the bottle... lol, completely irrational.

 

[Garak]

Well, weird dyes like purple aren't as resilient, or at least don't match up with the natural coloring of the oil as the time and miles add up. In any event, it doesn't stay purple for long.

Oddly enough, it's getting more common up here. Another local parts chain started carrying it. My supplier even has HPS on the shelf.

 

[OVERKILL]

Originally Posted By: CATERHAM
Whether one can notice the difference running a heavier than necessary oil makes that really shouldn't be the reason to do so.
At the back of many members minds, mostly newbies (and of course the hopeless belt and suspenders thicker is better set) it's a myth that there is greater high temp' protection in running a heavier grade especially if it's mentioned as an option by the manufacturer.
The fact of the matter is, there is no lubrication advantage to running the heavier oil (and if you read carefully what the OEMs recommend they all confirm it) but there are lots of reasons not to.



Ummmm, sure there is if you can drive oil temps high enough. That's why Ford runs 5w-50 in Coyote. Why BMW runs 10w-60 in various M-cars, why Ferrari does the same....etc. I mean these companies don't have engineers on staff that have managed to become hindered, licking windows and decide to just randomly cheerleader thick oil because it makes them feel funny in their private areas. They do it because it DOES in fact offer better high temp protection, arguing to the contrary is the only myth being perpetuated here.

Now that's not to say that running 10w-60 in a Subaru that gets driven by Grandma to the mall is a smart idea even if it is listed as an option in the manual, but that is clearly not what you've stated.

 

[HTSS_TR]

Originally Posted By: OVERKILL
Originally Posted By: CATERHAM
Whether one can notice the difference running a heavier than necessary oil makes that really shouldn't be the reason to do so.
At the back of many members minds, mostly newbies (and of course the hopeless belt and suspenders thicker is better set) it's a myth that there is greater high temp' protection in running a heavier grade especially if it's mentioned as an option by the manufacturer.
The fact of the matter is, there is no lubrication advantage to running the heavier oil (and if you read carefully what the OEMs recommend they all confirm it) but there are lots of reasons not to.



Ummmm, sure there is if you can drive oil temps high enough. That's why Ford runs 5w-50 in Coyote. Why BMW runs 10w-60 in various M-cars, why Ferrari does the same....etc. I mean these companies don't have engineers on staff that have managed to become hindered, licking windows and decide to just randomly cheerleader thick oil because it makes them feel funny in their private areas. They do it because it DOES in fact offer better high temp protection, arguing to the contrary is the only myth being perpetuated here.

Now that's not to say that running 10w-60 in a Subaru that gets driven by Grandma to the mall is a smart idea even if it is listed as an option in the manual, but that is clearly not what you've stated.

Honda engineers must smoke some unusual grass. They recommended conventional 10W30 in S2000 from the start in 1999 for all temp, then around 2004-2005 they recommended conventional 10W30 for ambient temp above 0F and 5W40 for ambient temp below 0F. They didn't mention that 5W40 was/is available only in synthetic.

 

[yvon_la]

magnesium have some positive effect ,but given zinc and molybdenum are still present in the oil I doubt it would be noticeable in normal driving .on paper magnesium and calcium are probably the only real need of an oil.(yep it means molybdenum and zinc could be booted,but I suspect it wont given how much zinc and molybdenum oil maker purchased.one also that would happen is the liklywood that the engine would be noisier,magnesium transmit sound a lot better then most material in oil ,that's probably why some stay away from magnesium.yep magnesium is the metrial of choice but being perceived worst because of sound transmission is probably not wanted.i don't know if this would in effect really be noisier given the fact we talk of theoretical; quantity of then 1600 per million.

 

[CATERHAM]

Ca and Mg are detergent/acid neutralizers, they are not anti-wear/ additives like Zn and Moly.

 

[Shannow]

Originally Posted By: MolaKule
Calcium is mainly a detergent and magnesium at one time was used in dispersants but its use has declined since magnesium leaves ash deposits.

Newer ashless dispersants are now used to disperse sludge molecules and soot.

Calcium compounds are "multifunctional" additives since they not only lift deposits, but also serves as a friction modifier and tbn booster.


Calcium friction modifier

 

[yvon_la]

how do you categorise one in one and the other in the other?mg as .1 coefficient of friction dry and .08 in lubricant
it is a bit higher then zinc but not enough to to actually mather
http://www.engineeringtoolbox.com/friction-coefficients-d_778.html
molybdenum at best is similar friction wise to magnesium but in lubricant perform less favorably vs magnesium .
http://www.industrialfriction.com/molybdenum/
that is why I try to understand what zinc and molybdenum have (for oil)that magnesium and calcium don't?

 

[CATERHAM]

Originally Posted By: OVERKILL
Originally Posted By: CATERHAM
Whether one can notice the difference running a heavier than necessary oil makes that really shouldn't be the reason to do so.
At the back of many members minds, mostly newbies (and of course the hopeless belt and suspenders thicker is better set) it's a myth that there is greater high temp' protection in running a heavier grade especially if it's mentioned as an option by the manufacturer.
The fact of the matter is, there is no lubrication advantage to running the heavier oil (and if you read carefully what the OEMs recommend they all confirm it) but there are lots of reasons not to.



Ummmm, sure there is if you can drive oil temps high enough. That's why Ford runs 5w-50 in Coyote. Why BMW runs 10w-60 in various M-cars, why Ferrari does the same....etc. I mean these companies don't have engineers on staff that have managed to become hindered, licking windows and decide to just randomly cheerleader thick oil because it makes them feel funny in their private areas. They do it because it DOES in fact offer better high temp protection, arguing to the contrary is the only myth being perpetuated here.

Now that's not to say that running 10w-60 in a Subaru that gets driven by Grandma to the mall is a smart idea even if it is listed as an option in the manual, but that is clearly not what you've stated.

And when 10W-60 and 5W-50 grades in your examples are specified are lighter grades also spec'd? The answer is no.
And using your Ford example, does Ford recommend anything heavier than the spec' 5W-20 for the Mustang GT even for track use regardless of how high the oil temp's get? Again the answer is no.

From an engineering view point there is more than one way to deal with high oil temp's than running heavier oil. In fact that's very much the last thing you want do with all the negatives associated with running heavier oil grades when you are not seeing high oil temp's.

My advise to anyone with a late model car, is to take full advantage of all the safety management systems that have been engineered into your car and run the lightest oil specified.
There is no lubrication benefit in using anything heavier.