Who's right? (or closer to right): Oil specification for my old Fiat Abarth, 5w40 or my new Honda SI, 0w20?

[ultraviolet]

Well, your post style sounds familiar, hence my comment.

i certainly have spent a lot of time reading on here, maybe i've just picked up some of the tone and vernacular that way.

ZDDP is only one component in anti-wear chemistry. There are numerous organic AW additives that won't show up in VOA's or UOA's that are used to improve performance in this department due to the limits imposed by the API on ZDDP. As I noted, the increase in viscosity, IF it reduces mixed and boundary, will reduce wear, but if it won't, then it doesn't. Then you are looking at oil chemistry, at which point the API standards are just the bare minimum. Euro spec's are significantly more stringent in this department as an example.

well, i suppose it's a good thing that my favourite oil is a euro-spec oil then!

Some engines are just loud. HEMI's sound like a sewing machine at idle due to the aforementioned valvetrain geometry. Some engines with solid followers will make some odd noises. Engines with hydraulic roller setups tend to be the quietest, but then you also have engines with loud injectors. Now, if you've got something knocking, there's something else going on, but that's a very specific sound pertaining to a very specific issue.

A tight valvetrain (one that needs adjustment, seat erosion) may actually be quieter than when properly adjusted. That's why it can be dangerous to assume based on sound without a history and what that specific engine sounds like healthy. Specific noises are normal for certain engine families and the absence of those noises may actually be a problem.

Amusingly, my sister's 330i and my wife's 328i that we owned, bought with wickedly high mileage and had clearly been abused, sounded exactly the same at idle. But the condition of the two engines under the valve cover was anything but similar. I can share some pics if you'd like.

My old 302HO had a bit of a rough idle (aftermarket cam) and a pretty heavy sewing machine sound from the valvetrain due to the 1.7 roller rockers. But at over 200,000 miles, it had factory spec oil pressure, was spotless inside and had perfect compression and leakdown. Mods are another thing, particularly with certain engine families.

Just some stuff to think about.

that is interesting to consider, i have some engines that are pretty worn out (low compression, especially) and they idle very quietly... and come to think of it, the 1st/2nd gen saturn dohc head, with its flat tappet bucket lifters, is pretty noisy when in good condition. i see your point here.

 

[ultraviolet]

What engines are known for bearing problems?

the hyundai theta ii comes to mind immediately, supposedly it was due to a manufacturing issue where debris remained in the crankshaft after machining, yet the problems have seemed to linger well past when hyundai claimed to resolve them. beyond bearing problems, there are quite a few motors that suffer from excessive oil consumption... the gm ecotec 2.4 and fca tigershark 2.4, no relation to one another although the shared displacement is a bit amusing, are the first 2 i can think of. there's also an assortment of hondas and toyotas that have such issues, including the prius which of course has always been a flagship for thin oils.

Are you implying that going from a 20 to a 30 grade oil will result in my engines lasting an additional 100k to 300K miles? 30 grade oils are barely thicker than 20 grade at operating temp.

yes, i am. "barely thicker" is a subjective measure, i'd say the difference is pretty significant.

If thicker truly is better, why don’t we all run 60 grade? Then our engines might last 1,000,000 miles!

there is a point when you are exceeding the tolerances of how the engine was designed. indeed, i put 0w40 in a prius once, partially due to the oil consumption issue, and it didn't really seem to like it. it didn't run badly exactly, it just seemed a little bit laboured, and i think 0w30 is as thick as that engine would like to run on. that is also a motor specifically engineered from the ground up to have tight clearances for ultimate fuel economy. this experience is actually why i mentioned in my initial reply that if one is concerned about going from 0w20 to (0,5)w40, 0w30 would be a decent compromise and still a step in the right direction. however, being a turbo performance motor, i strongly suspect the L15 in that civic has wider clearances than the prius motor, and would be more than happy on a 0w40.

I say all of this light heartedly. I don’t want to argue about this subject. The proof is in the pudding, and the pudding tastes pretty good these days.

i think it's good to discuss such matters, although some do seem to get a bit heated about it. you're correct that ultimately, we all have our own experiences and decide what works best for us based upon those.

 

[gregk24]

the hyundai theta ii comes to mind immediately, supposedly it was due to a manufacturing issue where debris remained in the crankshaft after machining, yet the problems have seemed to linger well past when hyundai claimed to resolve them. beyond bearing problems, there are quite a few motors that suffer from excessive oil consumption... the gm ecotec 2.4 and fca tigershark 2.4, no relation to one another although the shared displacement is a bit amusing, are the first 2 i can think of. there's also an assortment of hondas and toyotas that have such issues, including the prius which of course has always been a flagship for thin oils.


yes, i am. "barely thicker" is a subjective measure, i'd say the difference is pretty significant.


there is a point when you are exceeding the tolerances of how the engine was designed. indeed, i put 0w40 in a prius once, partially due to the oil consumption issue, and it didn't really seem to like it. it didn't run badly exactly, it just seemed a little bit laboured, and i think 0w30 is as thick as that engine would like to run on. that is also a motor specifically engineered from the ground up to have tight clearances for ultimate fuel economy. this experience is actually why i mentioned in my initial reply that if one is concerned about going from 0w20 to (0,5)w40, 0w30 would be a decent compromise and still a step in the right direction. however, being a turbo performance motor, i strongly suspect the L15 in that civic has wider clearances than the prius motor, and would be more than happy on a 0w40.


i think it's good to discuss such matters, although some do seem to get a bit heated about it. you're correct that ultimately, we all have our own experiences and decide what works best for us based upon those.

Hyundais issues were not oil grade specific. GM's 2.4 ecotec specs 5w30, so that is not a 20 grade issue. It seems those fail from user neglect or letting the oil level get too low. Honda and Toyota don't have any widespread bearing issues that I am aware of, not saying they don't exist but the overwhelming majority are very reliable on 20 grade oil.

 

[ultraviolet]

Hyundais issues were not oil grade specific. GM's 2.4 ecotec specs 5w30, so that is not a 20 grade issue. It seems those fail from user neglect or letting the oil level get too low. Honda and Toyota don't have any widespread bearing issues that I am aware of, not saying they don't exist but the overwhelming majority are very reliable on 20 grade oil.

with the ecotec/tigershark/various honda and toyota engines i was referring to oil consumption, rather than an immediate issue with bearing wear... however if there is bearing damage due to oil loss it will definitely become a major problem faster with a thinner oil. there are plenty of other modern motors i didn't mention/can't immediately think of with significant oil consumption issues, and that is one area that is definitely aggravated by thin oils.

 

[Accent Abuser]

the 0w20 is spec'd because it can net a slight improvement in fuel economy, and that's a top priority for manufacturers these days. no competent engineer is going to spec 0w20 for a turbo, performance engine if they're legitimately aiming to maximise durability. unfortunately, i'm quite sure the corporate decision-makers at honda are much more concerned with getting every last .01mpg they can, than they are with the engine's durability once out of warranty.

personally, i would suggest 0w40 or 5w40 for the vast majority of engines, and especially for a turbo motor like that. as you say, the fiat engine seemed to really like it, this is because a 40 oil offers far more protection than a 20 or even a 30. that said, i do always fret a bit about how the cam phasers, lifters, etc. in modern engines will react to an oil that much thicker, so if you're concerned with going up a solid 2 grades in operating viscosity, 0w30 would be a reasonable step in the right direction.

0w40 is the new 5w30. Any correctly designed VVT system will function just fine with a wide variety of viscosities.

 

[dlundblad]

It’s my understanding that A3/B4 oils don’t play well with DI engines because of the calcium levels. I use 0w40 (and such) in everything, but this is my only hesitation with it.

A plain Jane 5w30 synthetic should be reasonable for the Honda.

 

[Slow Car Sport Mode]

Maybe I'm missing something but what is the connection between a Honda engine and a Fiat engine ?

I'm wondering the same.

OP said "almost same displacement" but... Objection: Relevance.

 

[wemay]

i'm not guessing anything, i've researched the relationship between oil viscosity and bearing clearance extensively. any bearing manufacturer will tell you that a wider clearance means you need a thicker oil, whereas for a thinner oil you want a tighter clearance. check out this pdf from mahle, for example. an excerpt:

Lighter weight oils have less resistance to flow; consequently, their use will result in greater oil flow and possibly less oil pressure, especially at larger clearances. All oils thin out as they heat up; multigrade oils, however, don’t thin out as rapidly as straight grades. Original Equipment clearance specifications are necessarily tight due to the use of energy conserving lightweight oils, relatively high operating temperatures, and a concern for control of noise and vibration, especially in aluminum blocks. High Performance engines on the other hand, typically employ greater bearing clearances for a number of reasons. Their higher operating speeds result in considerably higher oil temperatures and an accompanying loss in oil viscosity due to fluid film friction that increases with shaft speed. Increased clearance provides less sensitivity to shaft, block, and connecting rod deflections and the resulting misalignments that result from the higher levels of loading in these engines. Use of synthetic oils with their better flow properties can help to reduce fluid film friction.

back to the j35, they obviously haven't changed the bearing diameter or width, nor added any coatings, if the part used is the same since 1999. as for the oil pump, it does appear they changed that in 2008, and i would agree that's almost certainly in order to produce adequate oil pressure with a thinner oil.


i'm not panicking, nor do i get the impression any others with a distaste for these thin oils are. we simply see that the nature of a thinner oil is to provide less effective lubrication than thicker oils, and consider the mpg/durability tradeoff to be an unacceptable compromise. there is a reason any bearing manufacturer will suggest a thicker oil for a performance/high load application. when it comes to uoas, the vast majority of those are also coming from people who don't drive their car with a "lead foot", and i have to wonder how many are from engines that have been running that sae20 oil for 200k+ miles. "running fine" does not equate to "protected to the utmost in extreme conditions", and personally i like to aim for the latter when maintaining any engine i have control over. listening to a friend's 200k mile k20 engine clatter away on its factory-spec 5w20 pains me immensely, and as soon as i put some 0w30 in there it quieted down quite nicely. this is a pattern i observe consistently on any high-mileage engine that was spec'd for an sae20 oil.

Is this thread a joke? First you start off with a question a novice would ask...

"Are these two engines [Fiat vs Honda] are more different than I'm guessing they are?"

Then you show the prowess of your investigative "skill" ?

C'mon man. Just another thinly veiled attempt at a thick vs thin tired thread.

 

[wemay]

Another tired thick vs thin thread. Groundhog day.

 

[ultraviolet]

Is this thread a joke? First you start off with a question a novice would ask...

"Are these two engines [Fiat vs Honda] are more different than I'm guessing they are?"

Then you show the prowess of your investigative "skill" ?

C'mon man. Just another thinly veiled attempt at a thick vs thin tired thread.

... your reading comprehension skills are astronomical. i'm not the one that started the thread, i simply provided a logical and concise answer to the op's question, which immediately attracted numerous attacks from people who seem to think cafe laws don't exist and that 0w20 is the only oil anyone should ever put in any engine ever. perhaps you should ensure you actually understand what's going on before blindly attacking others.

 

[SwampSurvivor]

20w-50 is the answer. That's what I run in everything

 

[ultraviolet]

20w-50 is the answer. That's what I run in everything

i do quite like mobil 1's 15w50 for engines with significant wear/low compression, it really woke up the 300k mile engine in tethys, my 1994 sw2. that said, i would NOT like to start an engine in sub-freezing temperatures with that oil in it, and i see no reason to choose such an oil for a motor like the saturn 1.9 if the engine is in good condition. for a jeep 4.0, on the other hand, i think it's generally speaking an excellent choice, although i'd still be wary of starting it up in the cold. overall, i like mobil 1 0w40 for "everything", 15w40 hdeo for dirty motors and severe oil burners, and the 15w50 for ones that are really worn out or old-school cast iron/pushrod stuff.

 

[doublebase]

Its the classic apples and oranges comparison. Yeah both are fruits, but.........

I look at it this way, and is strictly my opinion. Manufacturers are driven to design cars/engines by many factors. One biggie, nowadays, is fuel economy. When you extrapolate what just .5 MPG times a half million cars can net a company for meeting standards, it becomes apparent. Now, do they do this without taking into consideration the vast difference between the 2 oils mentioned and that one should give better MPG while the other should protect better? Probably not. I'm willing to bet that brand loyalty means a lot more to them than just "making it through warranty". Where do you think most of these folks would go back to if that were the case? So, do I think manufacturers have made design changes to accommodate the thinner, more efficient oils? Probably. Have lube engineers made design changes to thinner more efficient oils to protect better and last longer? Probably. Am I going to use the thinner oils in my newer cars? Probably not. But I'm old school, hard headed and change my oil every 3 months or 3K miles .

FWIW, my new Tiguan gets the 508 (Mostly. It's a blend) during warranty. Afterwards, maybe a nice 504. I mean, it IS a 2.0T VW engine after all, aren't they all the same?

I agree with most of this EXCEPT the brand loyalty part. I really think they don’t care all that much, and that’s because they don’t have to.

A lot of people on this planet think 100,000 miles is a lot for a car or truck. They do. And then they sell and buy a new one. I’d venture to guess that 90% of the cars and trucks on the road can make it to 100,000 miles without much in the way of out of pocket repairs. And then people are happy. Then they buy the same brand or something different. Therefore I don’t think a lot of effort is being put into vehicles for the purpose of retaining customers - all the manufacturer has to do is make something that will last 80,000-100,000 miles and the people who actually buy these vehicles NEW are “happy”. Most will have no idea, or concern, what those extended oil change intervals or lighter weight oils might do to an engine when it reaches 130,000 miles because they are LONG GONE AT THAT POINT. And driving their new car.

So, what I’m trying to say is...I don’t think manufacturers exactly have your best interest in mind when they spec these engines with a certain weight of oil, instead like you said, it’s a combination of factors. And I think if you’re taking that vehicle to 80,000-100,000 miles, you’ll be fine. If you’re taking it over that? You might want to think outside the lines of manufacturer “recommendations“. in my opinion.

 

[gregk24]

I agree with most of this EXCEPT the brand loyalty part. I really think they don’t care all that much, and that’s because they don’t have to.

A lot of people on this planet think 100,000 miles is a lot for a car or truck. They do. And then they sell and buy a new one. I’d venture to guess that 90% of the cars and trucks on the road can make it to 100,000 miles without much in the way of out of pocket repairs. And then people are happy. Then they buy the same brand or something different. Therefore I don’t think a lot of effort is being put into vehicles for the purpose of retaining customers - all the manufacturer has to do is make something that will last 80,000-100,000 miles and the people who actually buy these vehicles NEW are “happy”. Most will have no idea, or concern, what those extended oil change intervals or lighter weight oils might do to an engine when it reaches 130,000 miles because they are LONG GONE AT THAT POINT. And driving their new car.

So, what I’m trying to say is...I don’t think manufacturers exactly have your best interest in mind when they spec these engines with a certain weight of oil, instead like you said, it’s a combination of factors. And I think if you’re taking that vehicle to 80,000-100,000 miles, you’ll be fine. If you’re taking it over that? You might want to think outside the lines of manufacturer “recommendations“. in my opinion.

Then what do you say to the early adopters of 20 weight? (Honda / Ford) that now have over 200K and still going strong?

 

[Zaedock]

Then what do you say to the early adopters of 20 weight? (Honda / Ford) that now have over 200K and still going strong?

The funny thing is, 20 grade has been around since the ICE.

 

[kschachn]

The funny thing is, 20 grade has been around since the ICE.

Yes and no, SAE grading requirements change however. The 20-grade oil of yesteryear (such as the original Mobil 1 5W-20) is not the same as today’s 20-grade.

 

[Zaedock]

Yes and no, SAE grading requirements change however. The 20-grade oil of yesteryear (such as the original Mobil 1 5W-20) is not the same as today’s 20-grade.

Yes, of course requirements change to meet the current needs of the industry. I actually prefer the term evolve instead of change.

It still does not infer that 20 grades are designed to only meet economy targets without durability considerations, which has been consistently suggested in this thread.

 

[kschachn]

Yes, of course requirements change to meet the current needs of the industry. I actually prefer the term evolve instead of change.

It still does not infer that 20 grades are designed to only meet economy targets without durability considerations, which has been consistently suggested in this thread.

A 20-grade oil has an HT/HS which is right on the cusp of excessive wear without other design considerations. That’s why it is often back-specified to older engines whereas 16 and 8-grades are not. That doesn’t mean it is an optimal HT/HS for all driving conditions however.

 

[PimTac]

It’s the 0W that freaks people out.

 

[Zaedock]

A 20-grade oil has an HT/HS which is right on the cusp of excessive wear without other design considerations. That’s why it is often back-specified to older engines whereas 16 and 8-grades are not. That doesn’t mean it is an optimal HT/HS for all driving conditions however.

True, but if appropriately designed, it doesn't mean it can't be optimal for all driving conditions either. It's nothing you or I haven't discussed or read a bunch of times in our 17 years here.