I buy Mobil 1 oil by the case cause I drive my company car (Prius) so much and it needs 5k changes once a month. So I have tons of 5w/30 and that is what I put in the EVO for its first oil change at 1k. I didn't realize it came with 10w/30 in it. My questions is that isn't the oil the same viscosity for 5w/30 and 10w/30 when and operating temperature? Isn't the only difference when cold? I read in the owners manual and it said is was fine to use for areas where cold weather startabilty may be an issue which is not the case here in SE Louisiana. Can anyone think of a reason why I should not use the 5w/30. The only reason I can come up with is to aviod hassle at the dealer if I ever need them.

Tony

 

Cause the Oil cap says use 10w/30.....

 

Actually the oil cap doesn't say that at all. The cap on my Prius states a oil weight but not on the evo.

 

ok, Cause the Owners manual says too....


But then again it says to use 5w/30 in colder weather....IIRC

I do not see a problem using 5w/30 in a warm weather climate.

 

How much do you value your motor?Is it worth taking the chance...