VW Polo 1.4 TDI PD engine oil

[alankearn]

Since I bought my 1.4 TDI PD VW Polo in 2002 (yes I know its old but its only done 17,000 miles) I have changed the engine oil every year using the recommended 5w40 semi synthetic 505.01 oil (Millers). I have always bought a 5 litre container of oil but the engine only needs about 4 litres so I always have about a litre left, this builds up so about every fourth year it has built up so I dont have buy for that particular year.I now have a build up of about 3 litres and as it is near to oil change time I went to buy a 5 litre container of the recommended oil only to find Millers have discontinued it and say I should now use their recommended full synthetic (not semi) oil

See here
http://www.opieoils.co.uk/p-60252-mille ... e-oil.aspx

So now to my questions
I presume it is OK to mix synthetic and semi synthetic oils.
If the answer to this question is no would it be OK to mix a different manufacturers semi synthetic oil with the Millers oil

I am sure a few years ago I read that if you had used semi synthetic oil for a number of years and you changed to full synthetic there was a chance you could get oil leaks, any truth in this or is it a "old wifes tale".

[panason1c]

If I was you, I'd mix another make semi-synthetic oil with the Millers oil, that will be absolutely fine. just be sure that the 'other' oil is suitable for PD engines.