5-20 in MINI Cooper?

[gbony]

I have a 2006 MINI Cooper and some havoline synthetic 5-20 I am considering using as a winter oil (about NOV-APR). The car is normally aspirated and gets about 1200 miles/month from primarily commuting 25 miles each way to work on a highway (one stop sign each way). I live in the mountains of southern Oregon where it can get to -20 on rare occasions and is typically below 50 from NOV-APR. The car is a high revving SOHC with roller rockers, it turns 3000 rpm at 60 mph. Owners manual specs 5-30 and I was thinking of 5-30 castrol syntec because of its low viscosity, but I have quite a stash of the Havoline 5w20 on hand. I have been changing oil twice per year at about 7500 miles using Mobil 1 5w30 Extended Performance, instead of using the maintenance computer which would have me going 20000 miles between changes.
So what do all you experts think? What risk would I be running using the 5-20?

Thanks,
Guy

 

[JAG]

I'd find another use for the stash of 5W-20. A new car is a lot of money and it just seems wrong to not follow the manufacturers recommendations due to wanting to get rid of a stash of conventional oil. That's just me though. I don't think the engine will blow or anything on it.

 

[Big Jim]

Although I'm sure that the 5/20 would cause no trouble, I would stick with 5/30.

What is your warranty status? As long as you are under warranty, use only the factory specified fluid. Don't provide an opportunity for denying warranty should you have engine trouble while under warranty.

5/20 will provide no benefit for winter driving. When the oil is cold, both the 5/20 and 5w30 would be the same thickness. If anything, you would want to move to 0/30.

Even if you do change more often than the oil life monitor indicates, for cold weather, you should stay with synthetic.

 

[Gary Allan]

Simply do one UOA. It will tell you if your service is doing anything nasty with the 5w-20. One OCI isn't going to effect your long term ownership experience. Sure, the $ spent on the UOA makes using up the 5w-20 to get rid of it a moot point from a $ savings standpoint ..but you would also index your maintenance minder in terms of how the oil held up.