I'm using an engine flush tomorrow and changing the oil. In the past I've always stuck with 20W 50 but the guy that sorted my carbs out today advised 10W 40 semi-synthetic.
I know there's been a few questions regarding oil posted previously but I can't find one about using 10W 40 semi-synthetic.
I normally put in 15w-40 mineral in my V8 and it seems to go fine on this oil. I put in Texaco Havoline 15-40 in it cos its a good price here, and its recommended in the land rover handbook.
I use 20W-50, and change it after about 8000 km. I could imagine that 10W-40 is to thin. You should pay attention if you want to swap over from a mineral oil to a synthetic after your engine has done many miles on mineral oil. The synthetic oil can loosen the sediments in the engine, this sediments could cause a clogging of the lubrication bores, and this could cause engine damage.
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