M mints73 Joined 5 Dec 2009 Messages 31 Reaction score 2 Location Yorkshire Country 19 Jan 2011 #1 Can you mix oil ie if you need to top up between service and you are not sure make of oil in engine. Does it do any harm if semi synthetic and fully synthetic are mixed if the grade is similar.
Can you mix oil ie if you need to top up between service and you are not sure make of oil in engine. Does it do any harm if semi synthetic and fully synthetic are mixed if the grade is similar.
B Burnerman Joined 7 Feb 2008 Messages 25,096 Reaction score 5,289 Location Northumberland Country 19 Jan 2011 #2 Adding semi synthetic oil to fully synthetic lowers the specification of the fully synth to the semi...if you get my drift! Whether this is a big issue depends on the individual engine...but if its meant to use semi synthetic then its fine. John
Adding semi synthetic oil to fully synthetic lowers the specification of the fully synth to the semi...if you get my drift! Whether this is a big issue depends on the individual engine...but if its meant to use semi synthetic then its fine. John