Confessions of a Recovering Thickie

[Carlostrece]

Why wait until they are “clapped out” from the oil? Why not help to prevent excessive wear in the first place?

I didn't wait. Those engines were already worn out before they became my responsibility. I then had to make the best of a bad situation.

And why try and fine tune it within the same grade? What does that get you?

There can be a signifigant difference in cSt when comparing oils that are within same grade. I've seen different brands of 5w30 oils with 100KV cSt as low as 9.9 and as high as 12.3. Most are from 10 to 11. I prefer 11 to 11.5.

I fine tuned within grade to (hopefully) get less leaking on an old engine that's mechanically good, but has minor leak from gaskets or seals. No harm in trying. It helped my Buick recently.

Switching from a slightly thinner 5w30 to a slightly thicker 5w30 reduced the leaking my 28 year old Buick was having from valve cover gaskets. I switched from Maxlife Syn 10.7 cSt to Maxlife Blend 11 cSt. The leak after each drive reduced from a small puddle to only a few drops. This was obvious because I put down fresh cardboard under my car at the time I switched oils.

Possibly some of that reduction in leak was also Maxlife Blend being slightly less slippery than Maxlife Syn.

Years ago my autoshop instructor taught us that synthetic is slipperier than conventional and therefore syntheic can more easily slip past rings, seals and gaskets on old cars. He said that can be a concern with HM cars (from 70s, 80s, 90s). I think he was correct because my life experiences have been more leaks in old cars after switching to a syn of same cSt. If I switched to a syn with higher cSt then usually no problems.

That ^ was before HM oils existed, but I think it still partially applies even with HM oils.

I didn't just switch my 97 Buick to an oil with slightly heavier cSt. I also switched it from Maxlife Syn to Blend.

Edited in Later: It's also been my experience that the above can be compensated for by using a thicker syn to if you want to switch from conv to a syn in an old HM car, or by switching to a HM syn. Ideally both things: a thicker (within grade) HM syn.

Of course another good option (and cheaper) is to use a HM blend.

Edited in Later: I expect most of the younger and middle age guys to tell me I'm wrong and say my autoshop instructor was wrong. I'll bet most of the old guys will agree with what I said because we lived in an era when all cars started out using conventional and you had to consider these issues before deciding when or if to switch to synthetic, especially for HM 70s, 80s, 90s, & early 2000s cars, and especially in the time before HM oils existed. HM oils make the above topics less of a concern than in the past, but viscosity and type of oil (syn vs blend) still matter somewhat, especially for cars 2005 and older. IMO

 

[siriusc1024]

Engines aren’t designed “for” a grade. Any grade that isn’t too low of an HT/HS can be used.

Plus your use of winter ratings in the examples show you don’t really understand this.

Certain modern engines are designed with fuel efficiency in mind. Grade of oil is part of the package, and the thinner oil is a design consideration.

I know one feature of the 508 spec is a specific range of HT/HS. The designers are aware of that target.

Oil passages, clearances, bearing loading, etc. Not within the realm of possibility?

And, about the winter weights. Ever check out PDS's? Besides, the point of that comparison wasn't scientific. Back when 5w-30 was pretty much the standard how many people were out there prattling on about the inherent superior protection of 10w-40?

 

[OVERKILL]

Oil passages, clearances, bearing loading, etc. Not within the realm of possibility?

All of those things have to be designed to handle oil that's thousands of cP when the oil is cold. On the other hand, accommodations for oils with an HTHS below 2.6cP, due to more components operating in mixed/boundary, are made in terms of surface finishes as well as bearing width, to increase the load carrying capacity lost with the use of an oil with a lower HTHS.

Basically, engines can be designed to tolerate thinner oils, through certain mechanisms and design decisions. But engines are required to be able to handle extremely high viscosity due to ambient conditions.

 

[kschachn]

I know one feature of the 508 spec is a specific range of HT/HS. The designers are aware of that target.

Oil passages, clearances, bearing loading, etc. Not within the realm of possibility?

And, about the winter weights. Ever check out PDS's? Besides, the point of that comparison wasn't scientific. Back when 5w-30 was pretty much the standard how many people were out there prattling on about the inherent superior protection of 10w-40?

Yes and the range is the lowest they can go without causing unacceptable wear. That’s it.

As Overkill notes above, it’s about tolerating lower HT/HS to achieve a rather small decrease in fuel consumption.

 

[tolian21]

I have yet to find any proof that engines are now using tighter clearances in the past 10-15 years, maybe if you go back 30+ years, sure.

 

[ZeeOSix]

^^^ Yep, pretty much the same crank and rod journal bearing clearances have been used even back longer than 30 years. The basic rule used forever is the rod big end journal bearing has 0.001 inch clearance for every 1 inch of journal diameter. Crankshaft journal bearings can be tighter because they just rotate and don't reciprocate like rods do.

These are the clearances on a Ford Coyote 5.0L V8. Keep in mind that Ford specs both 5W-20 and 5W-50 in the Mustang depending on the intended use. That means it could use anything between a xW-20 and a xW-50. The point of this is to show that even an engine with these tight clearances can run a wide range of viscosity. I really don't know why people get locked into believing that "engines are designed for a specific narrow oil viscosity" ... they are not. They are designed to be able to use the lowest viscosity possible and still maintain a decent level of reliability and longevity driven by EPA/CAFE requirements. They do if driven pretty benign and not over stressed. But that doesn't automatically mean more or better engine wear protection and less wear over the long run can't be achieved by going up a grade - it can as been seen by many wear studies. And going up in viscosity does give more headroom to cover more possible extreme driving conditions.

If you run the numbers from the Coyote factory service manual specification below, using the middle of the clearance ranges, the crank bearing clearance is 0.001 inch per inch of journal diameter, and the rod bearing clearance is half of that at 0.0005 inch per inch of journal diameter. That's tight, yet this engine can run xW-50 all day long, even on the streets with normal driving. So this whole "engines are designed for a specific oil viscosity" is total nonsense, and a repetitive misconception on every chat board that discusses oil.

And here's info out of the XSR900 triple factory service manual. Again the bearing clearance is just as tight in a totally different engine design, and Yamaha specifies only xW-40 and xW-50 for this engine.

 

[ZeeOSix]

What if putting 5w-30 in an engine designed for 0w-20 made as much sense as putting 10w-40 in an engine designed for 5w-30?

Going up a grade in both cases makes the same sense. The only engines that have special design aspects to run oil thinner than xW-20 are the engines that specify 0W-8 and 0W-16. Those oils have their own designation and a different logo on the bottle because they don't want people putting that oil viscosity in engines not specifying it, for obvious reasons.

 

[ZeeOSix]

“Too thick” isn’t a grade off of OE spec: that’s more of an issue adding some crazy thick gear oil or grease, yeah, that’s too thick. But most engine oils are suitable, whereas the scope of most debates we have are optimization, not whether it’s an actual problem with engine health. It’s more of a preference and how much headroom one wants in a given application. That’s it regarding grade of oil.

To add, the "W" grade can be way more critical than the KV100 grade. Threads like this ultimately conclude that any engine can tolerate a wide range of KV100 grades. But use the wrong "W" grade in very cold climate start-ups and that can cause a lot more engine wear and possible damage, especially if the oil won't pump ... then you can get major engine damage.

 

[kschachn]

To add, the "W" grade can be way more critical than the KV100 grade. As threads like this ultimately conclude is that any engine can tolerate a wide range of KV100 grades. But use the wrong "W" grade in very cold climates and that can cause a lot more engine wear and possible damage, especially if the oil won't pump ... then you can get major engine damage.

The whole basis for a reconfiguration of SAE J300 back in the 90s and subsequent improvements on how the winter rating is measured.

 

[ZeeOSix]

The whole basis for a reconfiguration of SAE J300 back in the 90s and subsequent improvements on how the winter rating is measured.

Yes, SAE J300 specifically addresses "Cold Cranking" and "Pumpability" maximum viscosity for the "W" (winter) grades. Using a W grade higher than specified in the OM could cause more engine wear and/or damage.

 

[kschachn]

Yes, J300 specifically addresses "Cold Cranking" and "Pumpability" maximum viscosity for the "W" (winter) grades. Using a W grade higher than specified in the OM could cause more engine wear and/or damage.

View attachment 280439

Plus the revision added in a provision for the cooling rate of the oil, which was the problem that resulted in engine failures back in that day.

 

[ltslimjim]

To add, the "W" grade can be way more critical than the KV100 grade. Threads like this ultimately conclude that any engine can tolerate a wide range of KV100 grades. But use the wrong "W" grade in very cold climate start-ups and that can cause a lot more engine wear and possible damage, especially if the oil won't pump ... then you can get major engine damage.

Great point. I should have also included the cold properties; as @OVERKILL noted it destroys the whole “but that grade is too thick!” false claim.

I often don't include that aspect in my approach as I live in Atlanta. A cold winter for us occasionally hits single digits. Like once a decade. Typically, the coldest average winter is in the teens a few times.

And here I am, running 0w most of the time. lol

In part, I have this belief that the 0w may be an overall better oil; perhaps better base oil blend, when its of the EP / boutique oil variety; I know with bottom barrel OTS synthetics this is less likely to be true...but I've been meaning to ask if that is even based on something true / proven or just "most likely"?

Regardless, the vehicle I drive is so easy on the oil, I'm not necessarily concerned with a slight reduction in HTHS and a higher noack. If I was driving a TGDI I4 of recent generations, I wouldn't take that approach. I'd opt for 5w instead. Probably wouldn't be extending the intervals as much there either, so the w rating may not degrade as much in use.

 

[tolian21]

Is 0w vs 5w going to make a difference if your temperatures never drop under 20F in winter?

 

[Glenda W.]

Based on oil temperatures alone a 20 grade could be thicker than a 40 grade in the same engine in different climates. Engines simply cannot be viscosity sensitive or those who live in different extremes would be in serious trouble. Unfortunately it’s a very common misconception.

 

[ltslimjim]

Is 0w vs 5w going to make a difference if your temperatures never drop under 20F in winter?

For me? More of a preference overall chemistry of the oil.

EDIT: Although if I didn't need a 0w in a 20 grade; which looking back I did not, then I'd have opted for 5w-20 for better deposit resistance. I do regret using 0w-20 for extended intervals now that I know that about that grade. Learned that a few weeks ago from @OVERKILL ...

Now that I'm running 0w-30 it doesn't seem to make much difference. I don't need the benefits of the 5w in my case for this vehicle, although a more demanding engine I'd run 5w year round in Atlanta.

 

[tired]

Most people never lift the hood of their car - unless the "squirters" stop working.
The TPMS will force most people to at least take care of their tire pressure.
Many here on BITOG don't realize how few people care about oil, the way they do.

Yes I think the most recent data I saw (which was fairly old) is that only 15% of Americans change their own oil.

 

[Mechanician]

Yes I think the most recent data I saw (which was fairly old) is that only 15% of Americans change their own oil.

The point I'm trying to express is - the majority of people don't ever give their oil much thought.
And yet there are not a lot of good cars, with bad engines to be found.

 

[tired]

The point I'm trying to express is - the majority of people don't ever give their oil much thought.
And yet there are not a lot of good cars, with bad engines to be found.

Yes my point was in agreement with you.

 

[Hermann]

The point I'm trying to express is - the majority of people don't ever give their oil much thought.
And yet there are not a lot of good cars, with bad engines to be found.

Recently had 2 dealers push a oil change at me. I said I changed my own oil. You would have thought that I was committing a mortal sin.

 

[Carlostrece]

0w-20 has been a thing for a while now.

What if putting 5w-30 in an engine designed for 0w-20 made as much sense as putting 10w-40 in an engine designed for 5w-30?

It might make as much sense. I'm not sure. I say might because more recent engines after 2007 or maybe after 2010 or a bit later might have new/more issues to consider than the old 70s, 80s, 90s, and early 2000s engines that I'm accustomed to. I've heard that some newer cars are more sensitive to viscosity and/or additives package. I don't know.

So I'll have to defer to folks who know about newer cars made after 2007 issues and let them answer your question. My experience is only with cars made before 2008. For cars made after 2008, I don't know.

That said, my gut feeling is it'd probably be fine to step up from 0w20 to 5w30 in a high mileage car that was made after 2007. However that's just my best guess since I've never owned a car newer than 2007.

Also, if you chose a 0w30 or 5w30 that is thin for its grade (as some brands are) then it would only be slightly thicker than a typical 0w20. So in that case - not much difference.