Good idea. Might wanna tell your friend to do the same ^, if he's running it in his three 2K's (assumption...)

 

Lol, well he's owned 3 different ones over the years...not all at the same time. And yea he ran the 15W-40 in his all the time. I've been a huge fan of the Rotella lately on other applications...maybe I'll pick up some 10w-30 Rotella this weekend (if I can find it anywhere) and switch it.

 

5/40w is a good alternative to 10/30. I wouldn't run 15/40. To thick when cold and that's when distribution is really critical. 5 cold/40 hot/ is best of both worlds. 10/30 is pretty outdated. When Honda produced this car, there wasn't as advanced technology in oils that there are today. Many swear by running 0/30. That's a bit out of my comfort zone, especially when boosted and higher oil temps are seen. Thicker hot wight is added insurance, but not exceeding cold weight is important, its unnecessary to do so anyway in a tight tolerance motor such as ours.

 

I know Rotella T6 is good oil for turbocharged engines, and its the only oil that didn't make my engine noisy in my Mazdaspeed6. For NA applications, I think it may be overkill, due to the fact that it can handle a lot more heat than it's gonna see in an S (unless boosted). Try German Castrol 10W30. As others have stated, it works well and slows consumption for a lot of people.

 

Honda designed this engine with 10W-30, so even if it's "outdated" it still works under all tested operating conditions on this car. Just saying...

 

Sure, and there are now some that work better depending on the situation, such as climate, higher mileage as parts wear and tolerances widen/Excessive OIL CONSUMPTION. Being boosted, racing environments. These are all reasons to examine and choose an appropriate weight oil. I consider 10/30 a basis to work from on this engine, not the doctrine. In most applications its good and suitable, yes.

No one designs and engine around an oil, that wouldn't make any logical sense. They design a engine and then select a oil they feel best suits the engine specs, in the environment/market where the car will be sold, based on what they know at the time and what oil is available on the market at the time.

For this reason, Honda also recommends a 5/40 to be used in the appropriate climate, per the Manual. They also say standard or synthetic can be used.

5/40 simply has a broader temperature and therefor protection range, over a narrower weight such as 10/30. The only reason why 10/30 is recommend primarily, is because of the hot temp is thinner and will yield higher fuel efficiency, which is the driving force behind the EPA mandates/energy conserving oils bla bla.

 

Sure, and there are now some that work better depending on the situation, such as climate, higher mileage as parts wear and tolerances widen/Excessive OIL CONSUMPTION. Being boosted, racing environments. These are all reasons to examine and choose an appropriate weight oil. I consider 10/30 a basis to work from on this engine, not the doctrine. In most applications its good and suitable, yes.

No one designs and engine around an oil, that wouldn't make any logical sense. They design a engine and then select a oil they feel best suits the engine specs, in the environment/market where the car will be sold, based on what they know at the time and what oil is available on the market at the time.
[/quote]

I never said the engine was designed "around" an oil. I'm also talking about an OEM stock S engine, untouched. No one mentioned mods here. You are correct in that respect, modifying the engine or in extreme environments.

 

I will say that my engine is quieter, and seems smoother on the Rotella than with my previous 10w-30. And switching oil, combined with venting my PCV to atmosphere has all but eliminated the smoke puffs at idle when I come to a stop.

I cant decide how long I want to run this 15w-40. I just put it in yesterday, so I don't want to change it immediately. Might run it for a couple thousand miles then go back to a different 10w-30. I don't think a couple thousand miles on this oil will hurt it, if it would even ever be hurt at all.

 

thats really thick oil man...i would personally drain it, but its your motor so do what you want, but if you have the chance or means to put in a 5w30, 5w40, or 10w30, i would

 

Well its definitely thickER, but I don't know that I would call it really thick. I mean, some of the FI guys are running 20w-50. I understand the "need" for that at temperature, but really the only major concern here is on a cold start. At operating temperature 15w-40 is the same viscosity at 5w-40. And like I said, living in the south, I don't think it will be an issue except in the coldest winter months where it temporarily gets below freezing.

I can see your concern, but I don't think draining it is necessary, especially when there are some people who run this oil constantly, without issue. I'm not saying that its right, or a justification for me to continue using it, but I think the chances of it causing some kind of engine damage or failure are somewhere near zero. So in an act of financial cheapness and laziness, I really don't see the need to drain it like right now. I'll probably just run it at a shorter interval, then go back to the 10w-30. Obviously, if it starts acting funny, and starts acting abnormal going in/out of VTEC, then the situation would be more serious and would warrant a change immediately. But so far, the car seems really happy with it. Everything i can observe works as normal, and is a little quieter.


But hey this is a good discussion, and what the forums are for. I'm definitely no expert, so I'm here mostly to learn, but also share my experience.