I did a search on oil and have no idea about the info I found out - even more confused.

I also know this is semi covered in the Tech FAQ's but only refers to the mineral oil. Is it OK to use 10W40 Shell Helix (fully synth).

Also say for example a friend of a friend of a friend had put a drop of semi synth 10W30 in the car (not much maybe 250ml) would that casue some serious probs???

Believe it or not I am not technically minded and have never really had to top up previous cars and just need a straight answer so I know I am not destrying my car.

 

Firstly It is safe, but not necessarily advisable to mix oils from different manufacturers/grades, unless explicitly advised against.

The viscosity grades hold true for both Synthetic and "vanilla" (non synthetic oil).

So stick to the grades advised where possible.

0W and 5W are effectively the same grade (cold temp) except for the pour point difference.

-- Paul

*Edit* - Your 10W40 should be fine.

 

Cheers Paul,

If I now changed to 10W30 after topping up with 10W40 for a couple of months would that be bad???

Should I wait for an oil change at the next service???

 

I can't see it as been detrimental, however I would (personally) chose a grade and stick to it.

-- Paul