can i get away with 0w30 oil ?

[modmonster]

hi

i'm thinking an oil change will help reach my mpg aspirations. it says in my haynes manual that it takes 5w40 or 10w40 oil. can i get away with using 0w30 oil ? its winter here at the moment. would an oil pressure gauge help? i take it would not be advisable to run lean with this new oil.

would a gear box oil change score me more mpg's than engine oil change? i have a manual, petrol engine.

thanks for your help

[Cd]

I have 0 weight oil in my '93 Honda Civic with 130 something thousand miles.
I also fill it only half way between the add and full mark on my dipstick.

( My pea brain thinks that this would result in less friction for the engine. In reality, I'm probably hurting things.
Let's see how long I go before the motor dies. )

I didn't really notice any noticeable change in my mileage when I changed to zero weight, but that's my personal car. You might actually see a change.

[NachtRitter]

Was also curious about this, from someone that might have some technical information

[guudasitgets]

I think the spec for 0w-30 synthetic is ok to use in cars rated for 5w-30

[modmonster]

on the back of the 0w30 oil can it says "for most modern engines." my engine is only 9 years old so i think its cool no?

[KJSatz]

Making the jump from "10W40 or 5W40" to 0W30 is a bit stretchier than say getting 0W40, which would be (I think) fine. If it exists.

[IndyIan]

I assume your car isn't making alot of hp? Do you lug the engine for mileage?(3/4 throttle or more at 1800 rpm for example) Is the motor in good shape? not burning oil, or has any bad ticks or clanks, high mileage? Do you tow anything?
If all no, then you should be fine running almost any oil, but in your climate it makes more sense to use 10W30 to me, in general the closer the numbers the longer the oil lasts close to the original specs.
Switching both the engine and tranny fluid to synthetic should result in small increase in mpg as well. Without closely tracking mileage you probably won't notice.
Ian

[Compaq888]

Older engines require thicker oil due to bigger tolerances between the parts. Filling up really thin oil might cause some leaks. Modern engines have smaller tolerances due to technology bein advanced where the engine parts have smaller gaps between each other.

[Ryland]

if you really want to know what is going on then install an oil pressure gauge, with the larger gaps in an older engine an oil that is to thin will flow out of the bearings to fast and leave them dry, if you can keep enough oil pressure with thin oil then you are good.

[Cd]

Originally Posted by Ryland

if you really want to know what is going on then install an oil pressure gauge, with the larger gaps in an older engine an oil that is to thin will flow out of the bearings to fast and leave them dry, if you can keep enough oil pressure with thin oil then you are good.

What are the signs of bearing damage ?

I would hate to think I did something STEWPED like damage my bearings .

Also, can having the oil in the car at below 'full' ( mid way between add and full ) be a stupid thing ?