Engine oil 2.5n/a ex mil diesel

Hi will a 5w 30 semi synthetic oil be ok for a oil change ,as i have normally used mineral oil and have acquired some synthetic oil cheap GM dexos 1 5w 30 could it do any harm?
John.

simba1 said:

Hi will a 5w 30 semi synthetic oil be ok for a oil change ,as i have normally used mineral oil and have acquired some synthetic oil cheap GM dexos 1 5w 30 could it do any harm?
John.

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Quite likely it will do damage.
That sort of engine is designed for mineral oil.
Synthetic oil can cause the bores to glaze, gases to leak past the pistons, eventual damage to the pistons.
And is also too thin for the lubrication system of that engine.

I use 15/40 or 20/50 (or a mixture of them both depending how smokey things are getting).
Definitely has to be mineral oil.

Oh and there is a saying that any oil is better than no oil (but possibly not for long!)

Ok thanks guys will stick to mineral.

Plus it’ll leak out much faster...

You'd be better off filling the sump with used cooking oil.

Keep to mineral

5/30 is too thin,15/40 is preferable or 15/20 if the engines worn

samc88 said:

5/30 is too thin,15/40 is preferable or 15/20 if the engines worn

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Think you mean 20/50

kermit_rr said:

Think you mean 20/50

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Yes that one, thanks didn't spot that one