MG Car Repair: Oil Additives

Question
Hi Barrie,

Do you have any experience in using this product (additive to engine oil to improve viscosity and running and noise of engine)? It certainly has good reviews especially in old cars, but I was wondering if it is popular in MG ranks.

Many thanks.

Answer
Hi Pierre

I have no experience or feedback regarding the use of additives in my engine oil.  

My attitude is, buy a good quality multigrade oil designed for older cars, because it will have all the necessary additives.  I use Penrite, Comma and Duckhams.

Why would I want to add more additives?  

What does "improve the viscosity" mean?  Make it thicker?  Make it thinner?

Why would an additive improve "the running or the noise" of the engine?