I have a Subaru Impreza Turbo MY99 GC8.

I need to make a choice between two oils.

One is Mobile 1 0-40 and the other one is Mobile Longlife 5-30.

I change oil by months not miles since I don't drive my car that much, only about 4000 miles per year.

I've been using the Mobile 1 0-40 but a friend of mine told me that instead of having a really good oil on the car for a long period time, I should get the Mobile Longlife 5-30 and do the oil change more frequently. Is there any truth in that?

I'm going to do an oil change myself on Sunday and would really appreciate some feedback so I can get the right oil.

Update:
While we are on this subject. What is recommended on the gearbox and diff. Long time since I changed the oil on both.

 

both those oils are too thin.
most scooby specalists recommend 15w50 or 10w50 on all turbo engines.

i use silkolene 15w50

 

I found this:

http://cgi.ebay.co.uk/SUBARU-OIL-AND...item3356e79492

Thanks
Sam

 

never seen that kit before but looks fine

i use millers cfs 10w50 from opieoils

 

just had my car serviced at scoobyteknixs and they use
10W/60 MILLERS CFS

 

you in the engineers mate (spr)

 

why is it that they recommend 10w50 but here want to use Mobile1?

 

While we are on this subject. What is recommended on the gearbox and diff. Long time since I changed the oil on both.

 

10w40 semi synthetic is standard, dont use either of the oils you have stated, your handbook is a good place to start, and dont use a 10w60 either, its too thick when hot.

Tony