Yesterday i changed my oil and didn't realize i bought the wrong type... i know these cars call for 5W30.....is this a bad thing?

I live on Toronto if that means anything...temperature wise.

 

If I recall correctly, you put marginally thinner oil in there, which I don't think would really cause any issues other than making cold starts slightly easier this winter Maybe someone else could chime in and make sure you're safe, but I think you'll be fine.

 

It's not ideal, because once your car gets to operating temperature, your running lower viscosity than you should. It would be hard to measure the effect of running one oil change's worth of low-viscosity oil. If you are planning to keep the car for a long time, I would recommend changing it.

 

The MINI specs is a 5w-30, 5w40 heck, many use a 0w-40 in extreme cold......
since the oil is not a 30 or a 40 weight, I would consider changing it....I would keep the filter, just drain and fill...a quick thing...and the lighter oil will have worked as a engine flush of sorts!!
The 20 weight is what some companies are going to in many hybrids, and some of the newest motor designs to improve fuel economy...bet I bet some if the bearings, etc are sized for a lighter/thinner oil....

 

I should have mentioned i used Mobil 1 5W20 Synthetic.

 

Whoops yeah I confused myself. I forgot which number was which disregard my advice and take the advice of the knowledgable members

 

No, it's not ideal, temp's will have little or no bearing on it, the second # on your oil is "operating temp" viscosity, and a warm engine is a warm engine, no matter what the ambient.

If you decide not to change it right away do these 2 things:

1. Shorten the change interval, no more than 5000 miles, and check it very often.

2. Don't run the car high in rpm while it's in there, do your best to "short shift" as much as possible.

+ if in that time you have to add oil, add 0 or 5w-40

 

FWIW, straight from the Mini TIS as of 08/2007
This is the guide showing which guide to use...
http://oi50.tinypic.com/29785u.jpg
And this is the link to 5. Long life 1 which is for W11 among others...
http://oi47.tinypic.com/1oq43t.jpg


One for coolant as well... If you look close, there is a part number for a tanker truck of coolant. Wonder how much that would be.
http://oi49.tinypic.com/42b02.jpg