Oil viscosity- tune it or don't mess with it?

[LTC8K6]

http://www.thedieselstop.com/faq/9497faq/tsb/tsb/files/020109.pdf

Ford tsb I mentioned earlier.

 

[justfrank]

Volvo does not recommend 5w30 for my car at any ambient temperature above 86 degrees Fahrenheit. While I'm sure that there's enough wiggle-room in the spec that running 5w30 in 90-degree temps would not cause the engine to grenade, it's still not a good idea.

I'll stick with what the owner's manual says for my car, thank you:

ZV, I checked the owners manual too for my '95 850T and in my chart, the arrow in that diagram stops at 68F (highly doubt its accuracy) but if you check the link I provided earlier, and info found elsewhere, the difference between 5w30 and 10w30 is better flow at colder temps only.

Volvo changed their ideas on oil weight and it was either in the late 80s or early 90s.
I remember being at a Volvo technical training class back then and the instructor told us that Volvo did a lot of oil testing and decided that 5w30 was best and should be used year round. He got that info from Volvo's own engineers in Sweden, didn't just pull it out of his ass. Volvo dealers (and others too) eventually changed the bulk oil from what was 10w30 to 5w30 back then too, not because dealer parts people or management wanted to but because that's what Volvo wanted dealers to use in their engines.
I've NEVER once seen or heard of any engine failing prematurely due to the use of 5w30 oil, not with Volvo, not with Toyota. Many other manufactures have also been using 5w30 for ages now, again, no problems. That's everywhere in the world, year round. Weights like 10w30, 15w40, 20w50 is pretty "old school" now. We're not talking about Vintage air cooled Porsche engines.
My 850 now has 216K miles on it and has probably had 5w30 in it for years before I bought it (6 yrs ago). No noise, no consumption in 5K intervals (Mobil 1 5w30).
Most cars in the US have been getting 5w30 for years. On Toyota's oil fill caps (since at least the early 90s), it says to use 5w30. If 5w30's temp range was a problem, don't you think that'd show up in all those engines by now?
In car dealerships, I haven't seen 10w30 oil in stock for ages. It's always 5w30 for most, and for newer engines, 5w20 or synthetic 0w20 depending on what the fill cap says. Engines that now use the 0w20 go 10K miles on oil changes.

 

[Gillbot]

I live or travel to climates that are more extreme. I realize that the auto manufacturer give us their RECOMMENDATION for oil viscosity for overall and EPA figures. Because of that, I feel that I can tweak my oil selection a bit better. When I’m traveling to a VERY hot place in the summer, 5w20 is too thin for my liking and I’ll move to a 10w30. Likewise, in a different vehicle when traveling north in the winter, the standard 10w30 is too thick for my liking and I’ll drop to a 5w20 or so. Since I normally get oil changes twice a year, I will judge the driving I will be doing along with the anticipated climate and choose my oil accordingly. If I lived in San Francisco where the weather is always 72 degrees, I would thus follow the manufacturer’s recommendation.

I hope you aren't putting on a lot of miles.......

 

[Zenmervolt]

ZV, I checked the owners manual too for my '95 850T and in my chart, the arrow in that diagram stops at 68F (highly doubt its accuracy) but if you check the link I provided earlier, and info found elsewhere, the difference between 5w30 and 10w30 is better flow at colder temps only.

Volvo changed their ideas on oil weight and it was either in the late 80s or early 90s.
I remember being at a Volvo technical training class back then and the instructor told us that Volvo did a lot of oil testing and decided that 5w30 was best and should be used year round. He got that info from Volvo's own engineers in Sweden, didn't just pull it out of his ass. Volvo dealers (and others too) eventually changed the bulk oil from what was 10w30 to 5w30 back then too, not because dealer parts people or management wanted to but because that's what Volvo wanted dealers to use in their engines.
I've NEVER once seen or heard of any engine failing prematurely due to the use of 5w30 oil, not with Volvo, not with Toyota. Many other manufactures have also been using 5w30 for ages now, again, no problems. That's everywhere in the world, year round. Weights like 10w30, 15w40, 20w50 is pretty "old school" now. We're not talking about Vintage air cooled Porsche engines.
My 850 now has 216K miles on it and has probably had 5w30 in it for years before I bought it (6 yrs ago). No noise, no consumption in 5K intervals (Mobil 1 5w30).
Most cars in the US have been getting 5w30 for years. On Toyota's oil fill caps (since at least the early 90s), it says to use 5w30. If 5w30's temp range was a problem, don't you think that'd show up in all those engines by now?
In car dealerships, I haven't seen 10w30 oil in stock for ages. It's always 5w30 for most, and for newer engines, 5w20 or synthetic 0w20 depending on what the fill cap says. Engines that now use the 0w20 go 10K miles on oil changes.

Again, since people just aren't getting it: The problem is NOT THE OIL ITSELF. The problem is using an oil that the engine was not designed for.

I used my 951 (a liquid-cooled engine) as an example earlier because the manual calls for 20w50 oil. That's what the engine is designed for. That's what the passages are sized for. That's what the oil-cooler is sized for. You don't go switching to lighter oil because the engine is designed to use heavier oil and lighter weight won't hold up as well and will thin out too much to maintain pressure at hot idle.

Also, Volvo clearly didn't "change their ideas about oil weight" in the "late 80s or early 90s" since the image I gave you was from the owner's manual for a 1998 car. So it's newer than the information you're claiming, yet it clearly recommends 10w30 over 5w30. Not only that, but, taken directly from the owner's manual for a 2007 Volvo S80:

When temperatures exceed 86° F (30° C) in your area, Volvo recommends, for the protection of your engine, that you use a heavier weight oil, such as such as SAE 5W-40 or 0W-40.

What Volvo did change in the early 1990s was their engines. The old red block 4-cylinder was being phased out and the new modular 4/5/6 cylinder engines were coming into play. The more modern engines were designed for use with different oils than the old B-series fours and the boat-anchor PRV V6.

Also, you're simply wrong about there being no difference between the hot flow for 5w30 vs 10w30. A 5w30 oil has to have more viscosity modifiers and its going to end up as a thicker 5 weight oil at cold temps and a thinner 30 weight oil at higher temps than an alternative with a narrower viscosity spread. That's just the chemistry behind how multi-weight oils work. For each viscosity spec, there is a range within which an oil must perform, and some "30 weight" oils are thicker or thinner than other "30 weight" oils. A wider viscosity range means that an oil has a more difficult time meeting the specifications for either of the two ratings and generally a multi-weight oil will fall on the thicker end of the lower spec and the thinner end of the higher spec. (This does, of course, assume that all else is equal. Note that 0w30 oils are generally recommended to higher temperatures than 5w30 oils because 0w30 is, currently, only in synthetics and the superior thermal properties of synthetic oil are enough to overcome the issues associated with a wider viscosity spread.)

Of course, as I've already mentioned, there's not some magical tipping point at a specific ambient temperature; there's simply a gradual reduction in the ability of the oil to stay thick enough for the oil pump to maintain adequate pressure as ambient temperature increases. In the case of my '98 S70, the engineers clearly felt that 5w30 was not good enough for sustained loads at ambient temperatures greatly exceeding 86 degrees Fahrenheit. Is there likely to be any problem ever from a single person driving across flat roads on a 90-degree day with 5w30? No, of course not. But put 5 people in the car on a 95 degree day and push it hard going up Mt. Rainier and you're going to see at least some accelerated engine wear. Maybe not enough to show up for a while, but it'll be there.

You're right that, in general, engines don't "fail" (at least not completely) from using oil that is only slightly off from the recommendation, though I've seen issues with ring wear from people failing to change their oil or from prolonged use of much thinner than recommended oil. Still, most cars will have their electronics fail long before the mechanical bits of the engine really let go. That said, I will still always prefer proper maintenance over something that is merely "good enough." I tend to keep my things for a very long time.

ZV

 

[desy]

Ahhh right here

"What you're failing to take into account, however, is that engines are remarkable resilient things. Most engines will still "run" even if there are massive vacuum leaks and huge amounts of blow-by. "

Exactly 'remakable resiliant thing' which is why I said toooo much drama over one minor change in weight in a appliance car. There will be NO difference over the life of that vehicle , when cars can go hundreds of thousands of miles with REAL neglect

I don't propose never changing either, its just an example of how oil changes are taken WAY to seriously especially with such pidling little functional difference in what he is proposing

My boat is from 78 and my motorcycle from 82, so I tend to keep things a while too

 

[Zenmervolt]

Ahhh right here

"What you're failing to take into account, however, is that engines are remarkable resilient things. Most engines will still "run" even if there are massive vacuum leaks and huge amounts of blow-by. "

Exactly 'remakable resiliant thing' which is why I said toooo much drama over one minor change in weight in a appliance car. There will be NO difference over the life of that vehicle , when cars can go hundreds of thousands of miles with REAL neglect

I don't propose never changing either, its just an example of how oil changes are taken WAY to seriously especially with such pidling little functional difference in what he is proposing

My boat is from 78 and my motorcycle from 82, so I tend to keep things a while too

Fair enough. But I'm still not inclined to run 5w30 in my Volvo based on what the manual says. Yes, it's only a "minor" change, but I tend to put a good amount of stress on the engine and in summer when I heading up into the mountains with people and camping gear I don't need to be worrying about the fact that I'm outside what the engineers recommended for the car.

My point is simply to know what the owner's manual recommends. Stick with that and you know you're good. There's not likely to be any meaningful cost differential either.

ZV

 

[Ferzerp]

The oil in mine is not a recommendation either. It's pretty clear that it states use *only* this weight. It needs specific viscosity because of the cylinder deactivation.

 

[LTC8K6]

Bearing and other clearances are also factors in mfg viscosity selection.

 

[justfrank]

Also, Volvo clearly didn't "change their ideas about oil weight" in the "late 80s or early 90s" since the image I gave you was from the owner's manual for a 1998 car

Say whatever you want but I know what I know and I wasn't BSing, despite their owner manual info. I guess all the dealers everywhere who've been using nothing but 5w30 in ALL older engines (as advised by the manufacturers) have had it all wrong

 

[Zenmervolt]

Say whatever you want but I know what I know and I wasn't BSing, despite their owner manual info. I guess all the dealers everywhere who've been using nothing but 5w30 in ALL older engines (as advised by the manufacturers) have had it all wrong

That's fine. I'm sure that Volvo simply made mistakes in all the owners manuals that they've printed and put up on the web. And continued to make those same mistakes for a decade.

ZV

 

[jagec]

The former director of Castrol likely has far less understanding of the intricacies of lubrication than the posters on Bob Is The Oil Guy's forums.

ZV

To be fair, the posters on BITOG know a lot about lubrication...

 

[manimal]

I strongly doubt this. Even a car in fantastic condition is going to burn some amount of oil and there's no way that a car is going to go "100's of thousand miles" with the oil never being changed because at some point well before 100,000 miles it's going to run dry.

ZV

I just had a tiguan come in for service with 35k that cooked its oil after 15k miles with no oil change. So yes. No oil change = bad. Feel really bad for the guy since VW flagged it as customer abuse.

 

[Pacfanweb]

Say whatever you want but I know what I know and I wasn't BSing, despite their owner manual info. I guess all the dealers everywhere who've been using nothing but 5w30 in ALL older engines (as advised by the manufacturers) have had it all wrong

They are using that oil to save money, because since the newer stuff takes the 5w30 and that's what they mostly service.

They are NOT using it because they checked with the manufacturer and they okay'd it. It is only so they don't have to have another drum of oil that doesn't get used much.

Will it hurt? No, not really. Is it optimal? No, but then again, that depends on where you are located. Using 5w30 in a colder climate probably is less harmful. I wouldn't switch to it in the same car that resides in Texas, though.

Bottom line is, it's not THAT critical of a jump in viscosity. Not like you're using 5w30 in a car that specifies 20w50. (if any of those are even built now) That would be too much of a jump.

But usually there is an overlap of acceptable viscosities in the manual, depending on climate, where either is considered safe.

Personally, I use what the manual specifies. Why anyone would start changing something that engineers spent millions studying and oil companies spent millions designing is beyond me. That's about like all this snake oil that claims it improves engine wear, etc by mixing with your oil. Right. So you have all these different engines and many different oils, but this ONE product is magically going to make all of them better? Sure it will.

Use what the manual specifies, end of story.

 

[Pacfanweb]

I strongly doubt this. Even a car in fantastic condition is going to burn some amount of oil and there's no way that a car is going to go "100's of thousand miles" with the oil never being changed because at some point well before 100,000 miles it's going to run dry.

ZV

I've personally serviced or seen many cars come in over 50k with the original oil filter on them, having never been serviced at all. Oil was added, but never changed. Still running, and some of them were running seemingly okay.

I seriously doubt they were going to continue to run for "hundreds of thousands of miles", though.

If you do this for a living long enough, you'll become amazed at how stupid some people really are.

 

[Zenmervolt]

If you do this for a living long enough, you'll become amazed at how stupid some people really are.

I don't do it for a living, but I've seen people tie socks around radiator hoses in an attempt to stop leaks and one guy who was using a 12 volt battery out of a server UPS in his car...

A buddy of mine had a head out of an old Harley that had been "ported" by someone who appeared to have been using a rat-tail file for the job.

ZV