0W40 Can Ruin A 5W20/5W30 Oil Spec'd Engine?

[ZeeOSix]

Originally Posted By: Gokhan
TIB only point to government conspiracy and ignore important benefits of thinner oil such as better oil flow, which among other things, grossly reduces oil-filter and oil-pump bypass events as you pointed out.


Per the SAE viscosity rating, a 0W-40 should flow better at low temperature, and also protect better at high temperature (better HTHS) than say an oil rated at 5W-20. It should also help reduce oil filter and oil pump bypass events if it's more pumpable than 5W-20 at very low temperatures.

 

[Jim Allen]

Should also shear faster. Certainly will cost a lot more. Overkill for a lot of schleppers.

Difficult to find directly comparable CCV specs but I didn't see a huge difference a 5W20 syn and a 0W40 syn but there are so many variable that you would have to make sure you were comparing very similar base stocks (likely same brand) and comparing the same test methodology. I did see 2.75 to 3.0 HTHS on the 5W20 vs about 3.75 on the 0W40 (at least until it sheared). If circumstances dictated 0W40 level protection at the hot end, the CCV is very good so you wouldn't have a big cold performance loss there.

The Ideal:As thin as possible. As thick as necessary.

 

[BlueOvalFitter]

Originally Posted By: Jim Allen
Should also shear faster. Certainly will cost a lot more. Overkill for a lot of schleppers.

Difficult to find directly comparable CCV specs but I didn't see a huge difference a 5W20 syn and a 0W40 syn but there are so many variable that you would have to make sure you were comparing very similar base stocks (likely same brand) and comparing the same test methodology. I did see 2.75 to 3.0 HTHS on the 5W20 vs about 3.75 on the 0W40 (at least until it sheared). If circumstances dictated 0W40 level protection at the hot end, the CCV is very good so you wouldn't have a big cold performance loss there.

The Ideal:As thin as possible. As thick as necessary.

JA, where have you been hiding? I haven't seen you post on BITOG for awhile.

 

[ZeeOSix]

Originally Posted By: Jim Allen
The Ideal:As thin as possible. As thick as necessary.


And as has been said many times in these thick vs thin oil threads, the "thick as necessary" totally depends on the use of the vehicle while the oil is hot. A vehicle driven in a "normal and benign" way will live on 20 with oil at 200~225 F. A vehicle pushed very hard while towing or hauling heavy loads, or on a track will probably live better on 30, 40 or 50 depending how hot the oil is going to get (250~300+F).

Even 5W-20 could be fine on a track too if the vehicle has crazy oil coolers that would always keep the oil at 225 F all day long. It all depends on the expected max oil temperatures on how thin you can safely go.

 

[Gokhan]

Thin vs. thick debate reminded me a very interesting anecdote.

When I was kid, my mother used to sew a lot, women's dresses etc. We had this pedal-operated Veritas sewing machine. Occasionally the belt would break and I would repair it. It had to be lubricated routinely. One day we ran out of machine oil and I went to the Western-style convenience store around the corner that would sell anything from cow bells to school supplies, food, and so on. I grabbed a small bottle of machine oil and came back and lubed the sewing machine. However, the machine became almost impossible to pedal. There was way too much drag. It was requiring several times the normal foot force to pedal it. My mother was mad at me, saying that this thick oil was never intended for sewing machines and the sewing machines required thin oil. She sent me back to the store to get a bottle of thin oil intended for sewing machines. When I came back, she took a piece of cloth, opened the machine and patiently wiped off all the thick oil on the sliding parts while constantly yelling at me. I was feeling pretty stupid that I didn't know about this and she did. She then lubed it with the thin oil, and the machine started pedaling with very light foot force as normal. She could sew again!

There are piston-like parts in the sewing machine that operate in the hydrodynamic regime, in which the friction force is dictated by the oil viscosity, just as in the engine bearings.

In the sewing machine, the effect is obvious, since most of the energy is going into friction, as the actual sewing doesn't require much energy. In the car the frictional losses are a much smaller part of the engine output and people like to think that the effect of viscosity on friction is negligible, even though it's easily a few to several percent of your MPG.

 

[dblshock]

I'll discard the sewing machine analogy as a reach, we're talking automobile engines and motor oil here.

 

[wemay]

I posted this as a new thread but feel it fits right in, here...


https://www.bobistheoilguy.com/forums/ubbthreads.php/topics/4716390/Re:_17_Sonata_2.4L,_300+_miles#Post4716390


Castrol Edge 5W40 U.S. HTHS 3.7

A few notes after 300 miles on this oil...

Ambient temps over the last four days is 90F.
Mixed driving with 65% city.

The good: The car idles and runs very smoothly unless under hard acceleration (see below). Normal driving is scerene.
The bad: The car is noticeably sluggish under hard acceleration. It always feels like it's in Eco mode.
Not sure: Unless it's a gross difference, i don't know if i've taken any mpg hit.

The sluggishness may come from the fact this oil has a 3.7 HTHS? I don't know, but the performance difference is very noticeable.

 

[ZeeOSix]

Originally Posted By: wemay
Castrol Edge 5W40 U.S. HTHS 3.7

A few notes after 300 miles on this oil...

Ambient temps over the last four days is 90F.
Mixed driving with 65% city.

The good: The car idles and runs very smoothly unless under hard acceleration (see below). Normal driving is scerene.
The bad: The car is noticeably sluggish under hard acceleration. It always feels like it's in Eco mode.
Not sure: Unless it's a gross difference, i don't know if i've taken any mpg hit.

The sluggishness may come from the fact this oil has a 3.7 HTHS? I don't know, but the performance difference is very noticeable.


You're going to notice more of the oil's "shearing resistance" difference at higher RPM - that's why it felt "sluggish" when really getting on it. If just cruising around mellow (low RPM), it probably won't be noticeable, and either will the difference in gas mileage - especially in city driving when there are tons of variables that can influence gas mileage. If you cruised across the country at 75~80 MPH for hundreds of miles, you might see a slight difference in gas mileage.

 

[CR94]

Originally Posted By: ZeeOSix
... Per the SAE viscosity rating, a 0W-40 should flow better at low temperature, ... . It should also help reduce oil filter and oil pump bypass events if it's more pumpable than 5W-20 at very low temperatures. ...
Which should be of very little significance if you inhabit a place with reasonable climate, and the filter isn't defective.

 

[dave1251]

It is a common practice to use 10W30 or 15W40 HDEO for fleet use. Even for applications recommending 0W20. There is hundreds of thousands of dollars at stake in stated circumstances. This enough for me say using current SAE multigrades is better than fine. Common sense is a grade or two thicker provides greater leeway versus thin as possible.

 

[Garak]

Choosing for climate, too, never hurts. Akin to what I said already, my G, with VVEL and all that noise, allows for the entire spread of the 5w-30 grade, from the thinnest 5w-30 ILSAC to HDEO to C3. Even newer varieties allow 0w-20 up to a 5w-30 HDEO.

I'm the first person to want to choose a grade I can use all year - so, I'm a one grade guy for a vehicle. That's out of convenience and to avoid seasonal oil changes. Now, that doesn't translate into me believing that one grade is essential for one vehicle regardless of driving conditions and climate.

In the later years of the taxis, many went hundreds of thousands of miles with the 20 grades. I don't think an A3/B4 type lubricant would have hurt anything but the wallet.

 

[ZeeOSix]

Originally Posted By: Shannow
CATERHAM did great work correlating his oil pressure to HTHS ...


Sounds like a 540Rat test on steroids. Where's the error bars?

 

[mightymousetech]

Originally Posted By: Garak
I don't think an A3/B4 type lubricant would have hurt anything but the wallet.


Except you can get A3/B4 for the same price.

 

[Shannow]

Originally Posted By: ZeeOSix
Originally Posted By: Shannow
CATERHAM did great work correlating his oil pressure to HTHS ...


Sounds like a 540Rat test on steroids. Where's the error bars?

Yes, good point...

I bumped a thread and fixed the pics that I have
https://www.bobistheoilguy.com/forums/ub...ure#Post4307664

Note, while I agree with his testing method (above point aside), I don't agree with his application of the data and posits arising from it.

 

[ZeeOSix]

I see the old thread bumped ... thanks, I'll give it a read.

 

[Whimsey]

Originally Posted By: wemay
I posted this as a new thread but feel it fits right in, here...


https://www.bobistheoilguy.com/forums/ubbthreads.php/topics/4716390/Re:_17_Sonata_2.4L,_300+_miles#Post4716390


Castrol Edge 5W40 U.S. HTHS 3.7

A few notes after 300 miles on this oil...

Ambient temps over the last four days is 90F.
Mixed driving with 65% city.

The good: The car idles and runs very smoothly unless under hard acceleration (see below). Normal driving is scerene.
The bad: The car is noticeably sluggish under hard acceleration. It always feels like it's in Eco mode.
Not sure: Unless it's a gross difference, i don't know if i've taken any mpg hit.

The sluggishness may come from the fact this oil has a 3.7 HTHS? I don't know, but the performance difference is very noticeable.


Slightly different but the same outcome. When my 1996 Contour 2.0L Zetec was less than a year old "I knew better" being an an "old timer" that "thickerer is betterer" . Before BITOG I used synthetic 5W-50 instead of the 5W-30 oil spec'd. While it ran and started here in NJ the engine felt sluggish all year round and my mpg was reduced all year round. After 2 years I went back to 5W-30 Scheaffers synblend then to 5W-30 synthetic oils. The sluggishness disappeared and my mpg jumped up a lot. 10+ years later I replaced the valve cover and it was almost spotless under the valve cover and I don't use any measurable oil in 9,000+ miles OCI's. If you're not racing thicker oil does not seem to be ALWAYS better than the spec'd oil, but not in all cases now a days.

Whimsey

 

[Garak]

Originally Posted By: mightymousetech
Originally Posted By: Garak
I don't think an A3/B4 type lubricant would have hurt anything but the wallet.


Except you can get A3/B4 for the same price.

Yes, with a synthetic comparison. I was talking about a 5w-20 conventional for taxi use. Conventionals were used all along. Now, fuel economy for the taxis would take a hit with a heavier oil, too, of course. It wouldn't have hurt the engines in the least, though, and I don't doubt that many Crown Vic taxis were running 5w-30 or 10w-30 bulk conventional, too.

 

[userfriendly]

My guess that back in the day, those were LPG fueled. Easy to start, even @ -40C/F. I've seen 305 Chev RR crew vans go 1 million miles (1.6m km) on LPG & Plain Jane 10w30. One driver bought his favorite van for $500 10 years ago. It looks like ****, but it still runs.

 

[Garak]

LPG is not easy to start at -40 C, unless plugged in. In fact, at -40 C, impossible to start without being plugged in, or without a kettle of boiling water handy.

Aside from that, they were almost never turned off long enough to be problematic. They just ran QSGB 10w-30 year round, and never a concern at 10,000 km intervals. I remember suggesting synthetic to my dad to lengthen intervals then. He said they're long enough and it's nice to get under the car to take a look at things once in a while. If he saw me running HDEO in a car, he wouldn't be impressed. I suggested 10w-30 HDEO in bulk, and he didn't like even the notion of even the minor fuel economy hit, not one bit!

 

[userfriendly]

I ran an in-line circulating block heater into the LPG converter to keep it from freezing up on extreme cold starts.
If it froze, out came the hot water as you mentioned.
Propane dripping on your boot while fueling at -40 was another treat.
Regina & Moose Jaw always had the highest LPG prices west of the GTA.