I am considering changing to Mobil One synthetic oil due to hard starting in the bitter cold we have had. Car has 150k miles on it and has been on 20W50 oil from Castrol. What does everybody think? good idea or bad? Another possibility is a 5W30 reg oil ?

 

Thanks

I run Mobile-1 in my XT

How cold are we talking? I run castrol 20w50, and didn't have any trouble down to 15 degrees or so. Have you looked over your battery and starter recently? The starter could need rebuilding, or the battery could want changed - or a bit of both. Get something like an optima with lots of cranking amps.... running a thin oil like a 30 wieght in an engine with 150k doesn't sound like a particularly good idea to me. Got to keep that pressure up!

 

GD

http://www.bobistheoilguy.com

It's too late to switch to synthetic. It might work out ok, but it might end horribly too.

 

I would recommend switching to 5w30 or 10w30 castrol dino oil during the winter. It shouldn't decrease your oil pressure dangerously if at all, and it shouldn't leak any more than it does already (assuming it leaks since it's an old subaru motor).

mobil one is always a good idea unless you have oil leaks because it will find them quicker then regular oil and will make those leaks worse .if so just go with a 10w30 during the winter or put a block heater in

Yes, I too have heard that switching from Mineral to Synthetic oil can destroy your engine. Not to mention render you impotent and make long lost relatives call you up and ask "WHY did you do it??"

 

 

Mobil 1 is a very good oil. Not the absolute top notch maybe, but it has so many benefits above any mineral oil. I wish you guys Stateside could get the 5W-50 we get in the rest of the world. No cold start problems and no excessive vapor loss.