What would happen if you put Mobil 5/30 extended synthetic oil in your 06 HCH
to achieve 10,000 mile oil change intervals?
Do you think the mileage would go down?

Do you think it would be too thick?
Now on the internet I have read if you are driving in the area where the ambient temperature is consistently hot say above 85 and up it would be ok.

The 5W will flow not as good as “0” but it is still lower than “20” , in respect to the 0/20 specified by Honda, when the oil is cold,

So then a high ambient temp says 106 DEG. The engine will have oil flowing as 30 Weight. I don’t think it would matter since I also read Honda did it, that is lowered the rating to achieve a Raise there mileage rating,
any seat of the pants engineers out there who would like to contribute?

I'm really interested.

Isn't the Honda 0-20 oil already 10,000 mile oil?

I woudl not go with an x/30 oil. The second number is the rated viscosity at the engine's normal operating temp, so I would keep that the same. However, the first number, the "0" in the 0/20 oil, has to do with the viscoity from a cold start. For someone in 29 palms, you'll probably never start with the ambient air cool enough for that to matter, so 5w20 should be effectively the same thing. Although 0w20 is recommended, the manual in my '03 states that 5w20 is acceptable, so if you want to save money by going to a 5w20, you should be fine, I wouldn't go to a 30 though.

I agree with Mike. I would stay with x/20, and not creep up to x/30.

However, normal operating temperature for an engine is not 100 degrees. It's more like 160 or more degrees. So hot days in FL, or TX, or AZ even won't have your car starting out at normal operating temperature. A coolant thermostat stays closed (to let the engine heat up to normal operating temperature) until 160-180 degrees. Watch you coolant temperature gauge. IF you start out on a hot day with a cold car (been sitting at least several hours), the gauge will show COLD. It should warm up to NORMAL pretty quickly, but it does not start there.

Therefore, even though it is probably OK to use 5/20, it's not exactly the same as 0/20 for the first few minutes of driving. So, I'd bet your first few minutes of driving that the MPG would suffer more so than if you had 0/20 in it. Probably not a big MPG impact though, unless your driving trip is under 5 minutes.

Steve

STOP terrorism - Drive a HYBRID

Vehicles:
350 miles a week ------------ 2006 HCH II, Magnetic Pearl, w/NAVI (born on May 25, 2006)
350 miles a month ---------- 2003 Mazda Tribute ES-V6
350 miles a year (for now) - 1986 Mercedes 560SL

I use Mobil1 0w20 at 10K mile intervals on my '04 HCH. No problems after 66k miles.

-Charlie...

Same here... 0w20 Mobil1 and I'm going on 80k miles, again no problems. I use Mobil1 oil filters too.

Thanks for the impute. I agree on the 5W not being a problem in the desert. I also read the manual which states,” You may put the 5W-20 oil in the crankcase if 0W-20 is not available" so I went to 5 places and all they had was 5W-20.
I bought 4 qts of it & changed the oil & I noticed a lot of valve noise from the engine after. But maybe I'm just over reacting now. I had noticed it before with the Honda oil in the engine. When I tried to see if I could charge the battery like the book says revving the engine steady to 3000 RPM I noticed a lot of valve noise around 2200 RPM.With the Honda oil and it seemed louder with Mobil 1. I guess all will be ok. I plan to do 10,000 mile changes. Thanks For the help

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