Can too thick of oil be damaging?

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Originally Posted by CR94
Originally Posted by SonofJoe
... However it might be worth mentioning some of the very positive benefits of plopping a 'tight' Group I 20W50 in your engine...

- Greater Minimum Oil Film Thickness & higher HTHS. ...
- Low Noack Volatility ...
- Low VII polymer loading (one of the lowest for the 'typical' viscosity grades). Put this together with that low Noack, and you'll deffo see this reflected in low piston deposits on tests like the Sequence IIIF/IIIG. You won't get late onset oil control ring stickage (& out of control oil loss) with a tight Group I 20W50!
- Very good oil solvency. ...
- it can be produced on fully depreciated plants ...
And yet, despite all those advantages, you use 0W-20 yourself (as I believe you've mentioned in other threads)? That's interesting, or telling!
As a compromise in a mild climate, what do you think of 5W-20 or 10W-30 in an engine for which 0W-20 is specified? I've switched to 5W-20 myself, in hope of forestalling the infamous Toyota "ring-stickage." (I will disagree about calling it "late-onset," because it often occurs so early.)
Thanks!


I am running a Group I 20W-50 / 15W-40 HDEO Mix in both my cars right now.
 
Originally Posted by userfriendly
20W40 in locomotives (12X645 2-strokes) actually reduces oil consumption compared to straight SAE40. Chevron essentially blended 10W30 with SAE30 to arrive at 15W30, but it didn't catch on as I thought it would.
I mix SAE 40 with 10W30, or SAE 30 with 15W40, both good to a little below freezing, while shooting for a HTHS of around 3.8.
Right now I have 50/50 SAE30 & SAE 40 that I will have to drain if it gets too cold outside.



Good on you. I love Delo 15W-30. But it has gotten crazy expensive. My stash is from when it was cheap enough ...

SAE 30 or 40HD and a multi-vis blend is the best of both worlds
smile.gif
 
Originally Posted by BrocLuno
Originally Posted by userfriendly
20W40 in locomotives (12X645 2-strokes) actually reduces oil consumption compared to straight SAE40. Chevron essentially blended 10W30 with SAE30 to arrive at 15W30, but it didn't catch on as I thought it would.
I mix SAE 40 with 10W30, or SAE 30 with 15W40, both good to a little below freezing, while shooting for a HTHS of around 3.8.
Right now I have 50/50 SAE30 & SAE 40 that I will have to drain if it gets too cold outside.



Good on you. I love Delo 15W-30. But it has gotten crazy expensive. My stash is from when it was cheap enough ...

SAE 30 or 40HD and a multi-vis blend is the best of both worlds
smile.gif


I'm pretty sad I didn't buy more when it was $22 for three gallons on Amazon.
 
Originally Posted by SonofJoe
Originally Posted by CR94
Originally Posted by SonofJoe
... However it might be worth mentioning some of the very positive benefits of plopping a 'tight' Group I 20W50 in your engine...

- Greater Minimum Oil Film Thickness & higher HTHS. ...
- Low Noack Volatility ...
- Low VII polymer loading (one of the lowest for the 'typical' viscosity grades). Put this together with that low Noack, and you'll deffo see this reflected in low piston deposits on tests like the Sequence IIIF/IIIG. You won't get late onset oil control ring stickage (& out of control oil loss) with a tight Group I 20W50!
- Very good oil solvency. ...
- it can be produced on fully depreciated plants ...
And yet, despite all those advantages, you use 0W-20 yourself (as I believe you've mentioned in other threads)? That's interesting, or telling!
As a compromise in a mild climate, what do you think of 5W-20 or 10W-30 in an engine for which 0W-20 is specified? I've switched to 5W-20 myself, in hope of forestalling the infamous Toyota "ring-stickage." (I will disagree about calling it "late-onset," because it often occurs so early.)
Thanks!


You're quite right. I do use 0W20, not 20W50. That's for a couple of reasons.

First off my car's still under warranty. Suzuki spec 0W20 so that's what the car gets. I have had cause to claim on the warranty (an expensive LED dial/trip computer went wonky). The claim went through easy peasy because I'd had my yearly service done at the Suzuki dealership.

Second, when I buy cars, I prioritise fuel economy over every other thing (looks, performance, its ability to haul coal!). I don't think global warming is fake news. I want my grandson (plus his brother/sister due in January) to have a good life, so I do my bit & drive a car that does 72 mpg. For that you need 0W20 (not seen 0W16 here yet).

Third, because of what I did, I can probably still get oil for free, even the 'good stuff', if needed. Oil cost isn't a factor for me, nor is it for you, but for a lot of folks around the world it is. Hopefully my comments will make them feel a bit better about buying the cheap 20W50 they can afford.

Regarding oil control ring stick, my understanding is that if you're going to see it at all, it kicks in after 40k to 50k miles. For me now, that's a decade's worth of driving but before retiring, that might have been as low as a couple of years. Also, if you live in somewhere with very cold winters or constantly drive like a maniac, I'd expect to it to kick in even earlier. So it depends...

Fast or slow, it's definitely 'a thing' that should be being addressed by the industry but isn't. The trick is using a low Noack oil (deffo sub 10% & preferably sub 7%). That means the highest W-rating & lowest weight you can tolerate, full synthetic & interestingly the lowest oil spec (to minimise DI).

Hope that helps...



👠I feel the same way. Every oil has compromises and understanding that CAFE will gain you mpg with adequate protection is 100% fine with me. No vehicle I've ever owned consumed oil.
 
Last edited:
Originally Posted by FordCapriDriver


I am running a Group I 20W-50 / 15W-40 HDEO Mix in both my cars right now.


Probably fine, but they don't seem different enough viscosities for the mix to offer significant advantages, plus (unless you know different, and oil companies generally don't release much info) you've got the (admittedly slim) possibility of unexpected disimilar VII interactions

Part of my rationale for the 40:15W-40 was that there should only be one lot of VII's in the mix.
 
Originally Posted by SonofJoe
Typically a Group I 15W40 will contain about 7.5% of liquid 25 SSI OCP VII (equivalent to about 0.75% of solid rubber).

A 50:50 mix of 15W40 & SAE 40, containing 3.25% of VII would look like a very nice 20W40. I personally love 20W40s! I tend to steer people to 20W50s only because 20W40s are virtually impossible to find on shelves. I've put 20W40 through some of the toughest engine tests out there and they always come up smelling of roses. Of course they're not great on fuel economy but as out & out lubricants, they're the dogs bollocks.


I had a quick look at the available Castrol Go! (forgot the ! earlier) 20W-40 data here

https://msdspds.castrol.com/bpglis/FusionPDS.nsf/Files/656230DDA66D05D080257CB600401F94/$File/KRAE-9J2FSE.pdf

https://msdspds.castrol.com/bpglis/FusionPDS.nsf/Files/D068A778C38D8DE980257E4C0016A46D/$File/BPXE-9WZDPF.pdf

There are apparently two versions available, claiming SE and SG respecctively. Rather disappointingly, they both say they are suitable for catalyst-equipped exhaust systems, rather uncommon here.

This might suggest they've cut ZDDP (My understanding is that, while neither of these specs have a maximum ZDDP limit, there's no minimum, so nothing to stop them cutting it)

I dunno why you'd choose SE over SG.

This sort of relates to my earlier unresolved question as to why Halfords (=Comma, probably) Classic 20W-50 was SE, though that could just be cheapness of manufacture.

I've only noticed SG here, but I'd doubt there'll be a significant retail price difference, so I wonder why they both exist?
 
LOL doesn't hurt a thing in my '08 Subie! Calls for 5W30 and I'm running a Valvoline VR-1 20W50 OCI in her now. No issues to date with 2000+ miles on it. The little EJ255 turbo motor likes it, although I have noticed my fuel mileage has taken a small hit, down around 1.5-2mpg. average.
 
Originally Posted by ka9mnx
Originally Posted by wemay
Originally Posted by Shannow
wemay, nice effort at thin statesmanship.

GM, speccing the same engines in the US for Dex 1, and Oz as Dex 2 tells you something about what the engineers really think for the two markets.

The OP asked would thick damage anything...the answer is no.

edit...unlike the other situation...


In response to the op, i agree, it wouldn't. Now I'll ask the mods to change my user name to "The Statesman"👨â€ðŸ’¼. But everything i stated is true.

...and i would never go below what was recommended in my manual unless the engineers back spec'd the recommendation.


Hi wemay,

Ford back-spec'd my 1960's designed 4.9l (300ci) to 5w-20. Up until around 2005 the engine was spec'd for 10w-30. Around 2008 (and again 2015) I tried 5w-20 and it was a disaster. The engine knocked, timing gears banged and the engine was very noisy. IMO it was a mistake and went back to 10w-30 and everyone is happy now.



I don't believe the 300 Ford six was ever back spec'd to 5-20. If it was I would have kept using a 30 wt. What year was your 300?
 
Last edited:
There is a Ford TSB back-specing just about every engine from about 1990 on (4.0l excluded because of oil pump issues). My F150 is a 1993 (in my sig) and I wanted to see how it would work.
 
Originally Posted by ka9mnx
There is a Ford TSB back-specing just about every engine from about 1990 on (4.0l excluded because of oil pump issues). My F150 is a 1993 (in my sig) and I wanted to see how it would work.



I think there was also a Ford tsb about bumping up to a 10W40 in some engines to combat either wear or noise?
 
Originally Posted by aquariuscsm
I think there was also a Ford tsb about bumping up to a 10W40 in some engines to combat either wear or noise?

I think that had something to do with the Ford modulars with valvetrain noise or something like that. Someone here will remember for sure and probably even have a copy of the TSB.
 
The question of "heavy" oils comes down to the engine at hand... A Harley V-Twin will want a 20W-50 as it's a well clearanced motor with a dry sump system. It's 100 year old technology. A new Mazda GDI is a whole nuther beast.

Pistons with tight fitting rings, small drain back holes behind the oil control rings, and low tension rings (the trifecta of bad) will be very sensitive to viscosity and oil formula. And old iron block push rod V-8 with a good hone and decent cast iron rings (like Hastings) could care less what oil you put in there unless it's too light ...

Many Ford V8's suffer from tender oil pump drives. They can snap a drive if the viscosity goes too high ... Like heavy oil and a abnormally cold morning (been there, done that, more than once). Most Gm motors not so much. Chrysler stuff seems bullet proof in this regard.

It all depends on design, topology, and MFG Q/A. There is no one answer fits all ...
 
The difference between a 20 to 50 grade is very small. Running a 20 grade for the majority of driving situations is more than sufficient in the majority of American driving situations. A 50 grade is sufficient in the majority of American driving situations also. The bottom line neither will be nothing more than a contributing factor to engine longevity or failure. It will be the owner/maintainer/operator who will have the largest amount of control. Too thick or thin is never the right answer.
 
Originally Posted by aquariuscsm
Originally Posted by ka9mnx
There is a Ford TSB back-specing just about every engine from about 1990 on (4.0l excluded because of oil pump issues). My F150 is a 1993 (in my sig) and I wanted to see how it would work.



I think there was also a Ford tsb about bumping up to a 10W40 in some engines to combat either wear or noise?



Selective memory. It was not a TSB it was a Oasis message regarding how a tech was able to calm a noisy customer complaining about a noisy modular.
 
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