What happens if you use w30 oil on a car that is supposed to use w40?

Hi David and welcome to yahoo answers.


To answer your question, nothing.


If you used a 10w30 instead of the 10w40, IT is just a lighter weight oil. In fact if you live in a colder climate it will start a little easy er and run a little better then the 10w40.


Go ahead and run your car until the next oil change then change it back.


The will be no ill affects or wear then with the 10w40.


Thanks for your questionWhat happens if you use w30 oil on a car that is supposed to use w40?
The oil will thin out quicker than the 40 weight once the engine gets to full operating temperature. I would think the biggie would be that you'll have less oil pressure from the oil pump and over time that might cause premature wear on the engine's moving parts. The difference would be much smaller if you were talking about fully synthetic oils, but most of them are multi-viscosity and not a single number.





If you need to substitute 30 for 40 in an emergency, go ahead and do it. Even mixing multi- viscosity and single viscosity oils inan emergency is better than running below the minimum mark on the dipstick. You can always change the oil and filter when you get homeWhat happens if you use w30 oil on a car that is supposed to use w40?
nothing, except you may use more between oil changes.
it wont hurt anything, its just a lighter weight oil, thats all.