You are correct on the SAE “S” catagory located on the oil container…. The further down the alphabet that you go, the more refined the oil is…. I am a little over 40 years old and remember SF oil being on the shelf when I was in highschool… ‘S’ stands for spark (gasoline engine)…. the ‘C’ rating stands for compression (diesel engine)…. Some oils will have both an S rating and a C rating, such as Rotella T.

Dirt inside of an engine is sort of an urban legend….. How does ‘dirt’ get into the crankcase? Even a dirty air filter will only put dirt in the combustion chamber and ‘eat-up’ the piston rings… What the oil filter is filtering is solidified oil that has been too hot, or it is solidified because it has had an excessive amount of moisture added to it (remember a by-product of internal combustion engines is steam) and if it has ‘sludged-up’ it has been exposed to a lot of moisture because it has been in the engine too long…. the other source of dirt in the engine are impurities in the bottle of oil, that you are pouring in the engine…. The only other thing that would be filtered are pieces of the engine….. And that is lack of lubrication and normal wear (such as during the initial ‘break-in period’ when the vehicle is new).

We recommend oil changes be performed every 3750 miles with the most conventional engine oil we can get… We use regular Castrol GTX in our shop and it has the exact same SAE ‘SM” rating as the most expensive synthetic oil.

Finally, as for the lifetime ATF, automatic transmision fluid is used in hydraulic application in transmissions and again the only ‘dirt’ comes from within…. In theory, the things that ATF does is: it stays cool enough to properly lubricate the hard parts (valves in the valve body, the case bearings, planetary gears, ect.), it keeps fluid pressure under operation (which means the fluid itself has a sealing property to it), and it protects and keeps the internal rubber seals in the transmission lubricated …. In reality, it also suspends tiny pieces of material (such as the clutches in the clutch pak as they wear)… The construction of your Toyota transmission is completely different, than the Honda transmission…. The Honda transmission does not have a pan, nor does it have a filter…. Drain and fill the Honda ATF every year or 15,000 miles (whichever occurs first)… And only use Genuine Honda ATF when filling back up to the proper level. I also recommend that the fluid in the Toy transmission gets changed every 30,000 miles… Take the pan off the Toyota transmission to dump the fluid and install a new pan gasket during re-assembly…. You can also install a new filter at that time if you wish, because with the pan removed, there is the filter…. Then, simply properly fill with the Genuine Toyota fluid.

The key to using the lower weigh oil is for lubrication purposes. 10w40 (like tar) is too thick and that is why Honda specified the thinner weight of oil.

You may want to find a new mechanic.

The reason 10w40 had been put in by a former mechanic was because there was an oil leak that at the time couldn’t be located and he said with 10w40 it would drip slower. The leak has since been found and corrected. What is the right oil viscosity with such high mileage? Thanks 4 your help.

That blue sign with an “H” on it does not mean that they “can do no wrong”. In fact, many times these dealers could not conduct business in the manner at which they do, if they didn’t have that manufacturer’s sign to hide behind.

This is becoming painfully evident with the number of former GM dealers that had to close up because they lost their franchises a few months ago with the GM reorganization…..Just because these dealers were no longer a “franchised dealer”, did not mean that they could not service GM vehicles as an “independent dealer that “specialized” in those brands…..But many of them knew that their current business practices and conduct would not be acceptable and they would not be able to stay in business if they were not a franchised dealer….unless they started treating their customers much better, which they were obviously unwilling to do.

Another thing that you need to know is that American Honda rarely interferes with a franchised Honda dealer’s service department (unless it is a new car warranty situation)….. If you have a problem with a Honda franchised dealer, the American Honda customer service representitives in Torrence, CA will tell you to talk with the service manager of the dealership….So again, your relationship with your local Honda dealer is between you and the manager of that dealer…Honda basically says that in this relationship, “three would be a crowd”

Finally, oil weight is critical…..And Honda produced their engines to take one weight of oil under a very wide range of temperature changes…In other words: winter, spring, summer, or fall; the same weight oil can be used during an oil change….unless you live where extreme temperatures are present (look in your owners manual for these extreme temperture-to-oil weight adjustments). The fact that this dealer uses different engine oil weights would make me think that they don’t care and that they use different weights of oil, based on the best price of the oil from their supplier….In other words, “whatever makes the most profit for them” is what they will use….This could result in different oil weights and different oil brands being used, depending on what was “on sale” when they filled their bulk oil tank the last time.

I don’t blame you at all for wanting the weight of oil that was put in your vehicle to be documented on your invoices…..That is very responsible and smart.

If I were you, I would find another place to get my oil changed.

Ed

I must disagree with you about the S2000 engine being manufactured at the same (or even tighter) tolerences…That simply isn’t true. This engine consumes a little oil, straight out of the box and because the S2000 has a powerband effect at the 6000 RPM mark, it is being operated at much higher RPM levels.

As for CAFE standards: What would using a thinner engine oil have to do with an engine producing less emissions? The answer is one word “friction”.

You cannot have it both ways:

Many folks will say that 5w20 motor oil is too thin and that it will break down when the engine is being operated in higher RPM levels. But, if the oil was breaking down and not giving adequate lubrication, the engine would be consuming more fuel…because of excessive friction.

On the other side of the coin; if you use a heavier weight of crankcase oil in a Honda engine that calls for 5w20, it will consume more fuel….The reason that has been given is because the engine has been machined to much tighter tolerences and the heavier oil will not properly and completely lubricate (flow) to the entire crankcase bearing surfaces….leading to added and unnecessary friction.

I don’t know about you claims involving the Japanese & European side of Honda and nor does it matter…The U.S. version of the Civic stopped using a carburetor and went to fuel injection in all models of the Civic in 1988. Well into the 90s, Japanese Civic models were still using a carburetor and even a vacuum advance type of distributor. And many of the other Japanese versions of Honda products are not even seen in this country.

The fact is, that the guy that builds the engine says to use this weight of engine oil. I am not an engineer and I have 5w20 oil avaialable where I am. In fact, the Castrol 5W20 motor oil that our service department buys in bulk is actually a little cheaper than the 5w30 weight.

With American Honda saying this is the proper oil to use, with it being available, and with the cost being the same; Why wouldn’t you use the correct weight of engine oil?

Honda designed it…..Use what they recommend in the crankcase….It’s couldn’t be more simple than that.

Ed