Mixing Oils
Question from a friend:
Are there any reasons why (aeroshell) 15W50 Semi synthetic oil should NOT be used to top up an engine (Continenal C90) running on "straight" mineral 100 oil?
Mate says this is okay because teh aeroshell is "semi" synthetic. I'm not convinced.
Don't know the answer myself as I've always stuck to W80/100.
Over to you, clever people.
Rgds BEX