I watched a video by a mechanic (I can't bring myself to say "tech") replace the VTC actuator in a Fit. He said he thinks the 0W-20 oil is a bit thin, and he'd prefer at least a 5W-20. He said this after seeing the wear on the guides for the timing chain. Both of our Fits have about 100,000 miles on them. Any opinions?

EDITED: Looking online, it seems that 5W-30 is a good alternative. I'm at the point where I should buy more oil.

 

People are always trying to second guess the oil the manufacturer specifies for their car. In the case of oil the first two digits specify the oil thickness at cold startup. eg at startup "5W" is a thicker oil than "OW" oil. Once the oil gets warmed up the "20" indicates the thickness of the oil and in this case both oils have exactly the same thickness and will perform exactly the same at the warmer temperature.

I guess if someone wants a thicker oil at cold startup which won't flow very well and will produce a more sluggish start up go for it. I remember decades ago when I had 10W30 in my old beater (I didn't have the money for a change to 5W30 that year) and at -30C in the morning it was almost impossible to turn over, even with the block heater going.

 

Today's thinner synthetic oils are designed to be able to penetrate all parts of the engine easily.

Start running a thicker viscosity oil at startup, and you run the risk of the thicker oil not being able to penetrate all parts of the engine as easily, as well as making the engine work harder before the engine gets a chance to warm up.

I'm at a hard no for running anything other than manufacturer spec oil.

 

It's worth noting that a new API oil standard has now been released for the oil industry. API SP/GF6A/6B is now replaced by API SQ/GF7A/7B. The new oils provide better timing chain wear and better fuel economy etc etc. I would imagine the SQ oil is starting to show up on store shelves as the older SP oil disappears. A lot of features appear oriented towards turbo cars.

 

What does the owners manual actually specify for your climate?

 

I use 5w-20 in my 2018 EX-L, especially since I am in Tucson,AZ. What I have noticed is my fuel mileage has dropped a little but my car is much quieter now. The valve chatter has become almost non-existent.

 

One of the acknowledged reasons for thinner oil is better MPG.

 

Everybody already knows that 0W-20 flows better than 5W-20 at cold, but I don't think the difference between 0W and 5W is that massive, unless it's REALLY cold.

Most people seem to think that 0W-20 and 5W-20 are identical at operating temperatures, because, "20." But that isn't quite true.

0W-20 oil is basically 0W oil with certain amount of VIM (Viscosity Index Modifier) or just VI (Viscosity Improver) to make it behave as 20 at operating temperature.
5W-20 oil is basically 5W oil, but with MUCH LESS VIM, because 5W (at cold) is already much closer to 20 (at operating temperature).

Supposedly, good quality 10W (at cold) is almost perfectly 30 (at operating temperature), so 10W-30 has VERY LITTLE VIM.

In my book, lower the VIM, the better. This is why I use 5W-20 on my cars. And like @Rick Fertal I live in nice warm (HOT) desert climate, so I don't need 0W.
If you research wear tests, 5W-20 always does better (less wear) than 0W-20. In fact, 5W-20 and 5W-30 always score similarly. 10W-30 should in theory do even better, but I don't recall seeing any comparison involving all different weights in a single test. 30, of introduces other variables, which I'm not comfortable dealing with, so I just stick to 5W-20 for my cars, both of which have "0W-20" stamped on its oil caps.

 

@saveMT Hmm. Sounds like you are arguing that an oil with fewer additives — what we might think of as "straight oil" — is better than an oil with additives. So, the benefits of modern oils are not the result of additives, and we would better off going back to oils like we used 75 years ago?

"Better"? Over what period? In what applications?

 

I run 5w-30 full synthetic. It does just fine.

 

Don't tell any of the folks who splurge for Amsoil or Royal Purple or any other "boutique" oil. Their whole argument is that they have better additive packages than the crude (pun intended) oil the rest of us use.

 

Good comparison. It might get down to 0F here, but that's unusual. Both of our Fits have about 100,000 miles on them.

0W-20 vs 5W-20: What's the Difference

More - 0w-20 vs 5w-20 - Google Search

I'm sticking with 0W-20.

 

Actually, the thinner oil is for better fuel mileage.
I started running a little thicker oil because I am in Tucson, AZ and we might have 1 week of the year where it gets down to 20 degrees. The rest of the year's days I can use the added engine protection.

 

How much thicker is 5w-20 than 0w-20 at operating temperature, or as you say, even at cold start temperature for the majority of the year in Tucson?

 

When someone says additives, they're almost always talking about performance improving additives, like stuff that lowers wear, prevents seal degradation, oxidation, etc. VIM is merely there to increase viscosity. It's just some long polymer chains that prevents oil from getting too thin at temperature. They serve no other purposes. My point is, VIM does not help in any way with regular oil functions, and instead interferes slightly with oil performance, hence lower the better.

0W-20 and 5W-20 should have identical viscosity at operating temperatures. The difference is that 0W-20 achieves this through use of more VIM, because its base stock is thinner than that of 5W-20. Without VIM, 0W would be too thin at operating temperatures. That's my understanding. Take it or leave it.

 

My new case of Amsoil Signature Series Fully Synthetic 0W-20 just arrived.

I must be one of those crackheads who "splurge" on "boutique" oil. In fact, I go the whole nine yards and use OEM oil filters, too. Please don't tell anybody.





Note: Ninety percent of the posters on this forum are more concerned with saving 3 cents than they are with cars. I can get higher milage using thinner oils? Not only that. If I put my car in a museum and never drive it, it will last forever.

 

There are no simple answers to many car questions. I look for tests and comparisons of products online. OEM filters are often shown to be inferior to aftermarket. Fram filters usually get bad reviews. I've been using Bosch oil filters for years. Yes, they're "cheap." I also buy the cheapest full synthetic oil in 5-quart containers. I pour the required amount of oil into a separate jug, and I use that for oil changes so I don't have to measure it. I just dump it all in.

A high price does not mean high quality - in anything.

 

if 5w stops the VTEC rattle at startup, I'm in!...it probably gets -13CELCUIS min here

 

Or you could spend $2,500 to get the VTC replaced. 🤣

One of the mechanics doing a VTC job online thought that the wear on the chain was excessive, considering the mileage. He thought the 0W oil might be too light. He switched to an oil one step up in his vehicles. He may have been in Canada, not sure.

 

No offense but this sounds like confirmation bias, that is essentially the same as 0w-20 at operating temps, the 5 is just the winter or cold start up weight and is irrelevant once the oil is at operating temps. If anything you are potentially causing wear at start up in cold temps....