Mixing of 5W30 and 10W30

[kishorham]

Hi,
I am using Mobil1 5W30 Synthetic Oil, can I use 10W30? Any problem mixing these two grades?

Thanks
Kishor

[webbee]

The base stock is probably the only difference, so you should be able to mix them with out any problems. This is especially true because we are going into the heated time of year here in North America which requires a heaver base stock. I probably wouldn't do it in the winter time but you should be good to go. That's assuming you would be adding Mobil 1. There could be some incompatibilities between oil manufactures additive packages, whether this actually makes a difference... Haven't seen any data.

For oil related questions/answers I like Bob Is The Oil Guy, Forums:

http://theoildrop.server101.com/cgi/ultimatebb.cgi?

[sgillett]

I do that exact mix all the time in my '95 Carravan.
Oil change gets 5W30 and if I need to add one quart and they don't have 5w30 I put in 10W30.
IMHO If you are using the same brand there should be no problem with 1 quart in 4 quarts.
Scott

[auto_mran]

I mix 'em all the time, on accident and on purpose! However, I'm not using synthetic. No sludge, no leaks, no problems.

[Porsche gt1]

as you can tell no it is not a problem :)

[mcmotors]

You just end up with 7.5 W 30