Worn Engine - 0w-40 or 5w-50 for Max Longevity?

[CATERHAM]

Shell's position is of course ridiculous, because the HTHS vis is not proprietary. Anybody can have it tested if they want to spend around the 150 bucks it costs for the test.

The only reason companies like Shell, Castrol and even boutique companies like RLI don't provide this single most important viscosity figure is marketing. There's something about the spec' they are not happy with.

 

[Gannet167]

I agree. The rep I talked to asked me to send him an email he could forward on to management. I told them I like their oil and it's generally held in high regard on online forums. But consumers look at these performance numbers and would appreciate knowing them.

Not that oil these days is a bad product - it's come a long long way in the last few years. I found a few TINS of castrol that my dad bought at a garage sale years ago. They were from the late 70's - they're really only good now for lubricating the hinges on the car door.

But, by learning, asking about and comparing these types of numbers we only make the industry improve their products and help ourselves. Time to share the #'s Shell.

 

[21Rouge]

Originally Posted By: Gannet167
I'm going to go with PetroCanada Duron-E 0w-40. It's got great performance #'s

I called Shell and they say that HTHS #'s are "proprietary." I told them I don't want the secret formula, just the data that the competition is publishing. No luck.


And I get similar stonewalling from Esso when I have called re the NOACK # and HTHS # for their HDEO XD line of oils, specifically XD 0W30 and 0W40. Ridiculous. In comparison Petro Canada is very forthcoming re their oil stats.

 

[Velo_Fello]

Bear in mind that most engine wear occurs on startup. The oil has drained into the sump overnight.

Ester based synthetic oils have the property of adhering to the inside of an engine.

In my experience, this reduces startup noise from dry bearings.

I've also noticed it somewhat with Royal Purple, which has around 10-15% esters, I believe, added to a Grp III base stock.

 

[CATERHAM]

I've always suspected RP's so-called "Synerlec" additive is simply an ester of some sort. And I suspect you're likely right that RP only contains 10-15% of esters but that's all it takes to get the polar effect you've described.
Many oils contain a small amount of ester in their formulations, but there are other polar elements in motor such as moly and ZDDP and they may be more effective in reducing "dry starts".

BTW, motor oil will not drain off critical parts "overnight". It takes weeks for that to happen and once parts have been "plated" with phosphorus from the ZDDP molecule it will remain to provide the boundary lubrication if required.

Engines in good condition don't have "start-up noice" even after not being run for weeks; sufficient oil will remain in the bearings to prevent this. Yes, I've owned and know of new cars that have had a brief knock on start-up even after being shut down for a few hours due to loose bearings. On new cars it's totally unacceptable although it was common years ago on some, dare I say, domestic products.
Back in the 80's I returned a Chevy Celebrity with a 2.8L V6 that did it and got a new car. My dad did the same thing back in the 70's with a Dodge slant 6 and got a complete refund.

 

[azsynthetic]

Originally Posted By: Velo_Fello


I've also noticed it somewhat with Royal Purple, which has around 10-15% esters, I believe, added to a Grp III base stock.


RP base stock is not group III per their FAQ on their website. I also doubt that you could hear the startup noise of "dry bearing" taken into account other engine noises. There are startup noises in any auto engine. To pin point the exact sources takes more than a pair of ears.

 

[Velo_Fello]

Originally Posted By: azsynthetic

I also doubt that you could hear the startup noise of "dry bearing" taken into account other engine noises. There are startup noises in any auto engine. To pin point the exact sources takes more than a pair of ears.


How about rod knock from seriously worn big end bearings with no oil to cushion it?

How about that massive clattering noise vanishing after 5 seconds after the oil gets pumped into the dry bearings?

And how about that noise at startup vanishing completely with the use of an oil containing Grp V esters?

I can assure you a pair of ears are plenty good enough.