Does heavier oil = quieter, smoother engine?

[KzMitch]

Just a hypothetical question.
Fill a cup full of water and a cup full of oil. Set both down on a table. Bump the table and disturb the liquids in the cup. The surface of the water would move much more than the oil. Agreed?

All conditions being equal, would the same engine run any smoother/quieter with, for example, Xw50 than Xw20?
I'd have to believe that higher resistance to flow would have a greater effect absorbing vibration and deadening sound.

I think this same principle applies to liquid-filled harmonic balancers, viscous fan clutches, and motorcycle suspension.
Perhaps not a difference you'd notice, but I would think it would be measurable on some small scale, much in the same way a small increase in MPG is observed with a lighter oil.

 

[Hokiefyd]

It does in my experience. Note I'm using xW-30 oil in my 5W-20 spec'd Honda...

 

[Olas]

It depends on the variables..

If the oil in the sump is too thin then going thicker should see less NVH, but at the same time if you use 0w20 as per e owners manual, and then change it out for SAE 70 it would probably result in more NVH.

So it depends if that thicker oil puts you in to the viscosity range that the engineers built the car for, or if it takes you out of that range..

 

[A_Harman]

The viscosity of the silicone fluids in torsional dampers are orders of magnitude higher than motor oils at room temperature. Dampers I have worked with have fluid that start at 30,000 centistokes and go up to 60,000, even 120,000.

The ability of a liquid to dampen out vibrations doesn't have much to do with mechanical noise produced by an engine. I have found that piston slap in my Camaro actually seems higher with a thicker oil. Lifter noise is usually better solved by putting in a thinner oil.

 

[Swift101]

It does in my case, big time.

 

[3800Series]

It seems too, i have 10w30 Delo400 in my Regal. Its very quiet but its started to have a lifter tick. When I added a quart of MMO it fixed that some im just thinking the lifters didn't like the Delo since 5he run on the thicker side.

Overall tho I wanna say yes, but I also do contribute the lifter tick to the thick oil also.

 

[Errtt]

I've found sometimes it does just as well as sometimes it does not.
I last I tried a heavier oil in the wife's SUV and it became more noisy. Although I noticed it myself, wife also kept saying it keeps ticking. Changed back to the usual and all quiet now. Same filter used in both cases.

 

[HerrStig]

T6 is often mentioned by Toyota owners as helping NVH. It's worth a try. Sure not going to hurt anything and Walmart carries it.

 

[KzMitch]

In my little world's experience, European cars seem to have a certain "feel" to then. Many of them are spec'd for heavier oil.

Coincidence?

 

[19jacobob93]

Absolutely agree with everyone saying thicker oil actually makes lifter tick worse, the opposite of what most people think! With 10w40 my lifters clatter like crazy it's embarrassing haha but with 10w30 they are almost silent

 

[SnowDrifter]

My friend has a 1970 VW beetle, was running 20w50 in it. Talked him to a 5w30 (original spec is straight 30) and jos runs quieter.

Same kids parents ran 20w50 in their 325i. Older one, e30. Same gig, talked them into switching to 5w40 and the ticking noise when cold has completely gone away.

In my own car, Forester SG non turbo. Played around with varying oils from 0w20 to 10w40. Noticed the thicker I went, the louder my piston slap became. 5w20, 0w20, 0w30 were the quietest in that regard. I settled on running 0w30

My mom's vehicle, jeep wrangler with the 4.0, which I'm in charge of maintenance for had a cold-tick when running 15w40 diesel oil. Tick is not present when running 5w30.

I'm not sure that blindly going thicker is the best way to go about things. If you have a specific problem like worn bearings causing low pressure, it's a different story. But in the cases I've seen, with well maintained cars, thicker was not better from a noise regard. I used to be on the thicker is better bandwagon till I started playing around with it. I've seen greae results with using a proper hot viscosity, but running 0wXX or 5wXX

 

[HerrStig]

Originally Posted By: 19jacobob93
Absolutely agree with everyone saying thicker oil actually makes lifter tick worse, the opposite of what most people think! With 10w40 my lifters clatter like crazy it's embarrassing haha but with 10w30 they are almost silent
And does it help with solid lifter engines?

 

[SnowDrifter]

Current theory is pretty there are lots of things in the motor that are splash lubricated. While thicker oil might work in the cup analogy, if it doesn't get where it's needed there's going to be more noise

 

[horse123]

This forum sure is going to have lots of oil leaks and other issues related to excessive wear in a couple years when all these people using non spec oil have their engines worn down.

 

[Michael_P]

When experimenting in one direction (thick or thin), you will reach a point of diminishing returns. Sometimes sooner than you might think.

Whether you are trying to achieve smoothness or reduced oil consumption, sometimes thicker oils can result in greater oil consumption. Especially in the case of low tension piston rings. A thick oil can cause the rings to push into the ring valleys on the piston thus increasing consumption.

 

[The_Jeff]

If your injectors aren't balanced perfectly or you have a tiny I/M gasket vacuum leak, the increased work the engine has to do to just idle through thicker oil will use more fuel and cut the percent disparity between rich and lean cylinders, and run better.

 

[Smokescreen]

Non-spec.

Upon a search of your particular engine the "worldwide" oil weight applications, many may be surprised at what they find as to what they see here in North America vs elsewhere.

For example, in the North American owners manual for the 10th gen Toyota Corolla 1.8L (which is a world spec engine), there is only 5w20 and 0w20 oils strongly recommended. If one were to look outside this continent you would see this:

"Toyota genuine oil or equivalent
Oil grade - 20w-50 and 15w 40
API grade SL or SM multigrade
10w-30, 5w30, 5w-20 and 0w-20
API grade SL "energy conserving"
SM "energy conserving"
ILSAC multigrade engine oil

As this is for the same world wide engine for this vehicle, the argument for not moving to a different weight (should you choose) is not an issue and certainly not cause an untimely demise to the engine.

I am not advocating the use of heavier weights, just that you research your engine and know more about its design.

 

[mclasser]

Seems to be the case in older VQ35's that burn oil and have a timing chain rattle. 10W40 is regarded as a Godsend for these engines. FYI: 5W30 is factory spec.

 

[tig1]

Sloshing a cup of water compared to sloshing a cup of oil. The major oil producers may need to look into this type of test for their next formulations.

 

[Hokiefyd]

Originally Posted By: Smokescreen
Upon a search of your particular engine the "worldwide" oil weight applications, many may be surprised at what they find as to what they see here in North America vs elsewhere.


Indeed. Pick the grade you want to use or like the best, and use it. Grades of oil indicate their viscosity at operating temperatures. With a cold engine, your oil's actual viscosity is orders of magnitude above the desired "hot" viscosity. And until the oil fully reaches its "hot" temperature, its viscosity will remain far higher than most think.

It's a non-issue. Pick what you like and use it.