Also, I'd be interested how Llanigraham knows the formulations of the BP oils?

 

My father worked for one of the competitors!! 

I'm sure it was. However, one of my previous jobs was running the analytical laboratory of said major oil supplier. We investigated problems exactly like the one you described all the time. In every single case there was some other factor at work to cause the problem.

Could you please give some examples? I am asking because many Skoda and VW owners in Moscow faced a strange problem this winter: engine oil turned into jelly at relatively high negative temperatures, for example, at -5 degrees Celsius after a very short time in the engine (like 2000 km). Otherwise the oil maintained all of its characteristics. The problem was confined to Moscow region only. Journalists even coined the term "oil plague" for that (actually it describes two different phenomena, i'll write about the second one later). No one named the reason but there is an assumption why it happened. Though this has nothing to do with mixing oils, it shows that oil manufacturers do not always know everything about how their products can behave.

One famous example is the customer who swore blind they had topped their engine up with our oil just before the engine seized. Analysis of the oil residue found the presence of vegetable oil, which was most likely added at the top up when someone in the household had emptied the deep fat fryer into a handy empty container. We've had similar outcomes when someone tried to run a fleet of diesel engines on unrefined vegetable oil (as a fuel).

I am aware of the Russian situation and the likely reasons for it. Of course you can't always predict what will happen when things go wrong, but mixing two common oils together is a normal situation that is easy to test and predict.

I bought some Castrol Edge 5w 30 fully synthetic a week ago off e-bay. At £32.99 for 4L + 1L inc p&p it was the best price I could find. It is the VW507 and compatable with dpf engines.They have re-listed so it looks like they have some left.

 

http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=171301945919

 

Colin

Going back to the date thing, then I noticed that the Castrol 1ltr bottles often have a use by date but Comma oil (from our only local motor factors) does not :wonder:

 

Tend to use either brand myself, as they are obviously to 504/507 which all our cars will take.

 

 

TP

I bought some Castrol Edge 5w 30 fully synthetic a week ago off e-bay. At £32.99 for 4L + 1L inc p&p it was the best price I could find. It is the VW507 and compatable with dpf engines.They have re-listed so it looks like they have some left.

 

http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=171301945919

 

Colin

Good find!