Topping Up Engine Oil

[Welly]

If an engine has been run on Semi-Syn Mineral oil then you should not add Fully Synthetic. Fully Syn reacts differently and can 'lift' old waxy deposits which would have sat there quite happily before.

I'm no chemist but have studied engine oils for private use, including spending time speaking with a Fuchs/Silkolene distributor many times on this very subject and the general approach is stick with whatever oil was in the engine from day one unless you want to strip the engine and clean all the surfaces ready for a different 'type' of oil.

[Bailes1992]

If an engine has been run on Semi-Syn Mineral oil then you should not add Fully Synthetic. Fully Syn reacts differently and can 'lift' old waxy deposits which would have sat there quite happily before.

I'm no chemist but have studied engine oils for private use, including spending time speaking with a Fuchs/Silkolene distributor many times on this very subject and the general approach is stick with whatever oil was in the engine from day one unless you want to strip the engine and clean all the surfaces ready for a different 'type' of oil.

I went from 5w30 semi to fully on the focus with no real issues.

Was chatting to DarrenJLobb who is the owner of the 200bhp+ 306 which is quite famous among Pug groups.
He mentioned that the XUD/HDi's only have issues with Ester based Fully Synthetic oils.
Most people seem to go to Peugeot and get Total 9000 5w40 Fully synth and as far as I know there have been no reported issues.

I think the best thing to do would to change to fully synth and change the oil again 1000miles later.

Although I am playing it safe and sticking with Semi Synthetic.

I may try some Castrol GTX High mileage next. Apparently allows seals to swell to avoid future leaks... Which as we know would help any pug

[OdinEidolon]

Most people seem to go to Peugeot and get Total 9000 5w40 Fully synth and as far as I know there have been no reported issues.

Peugeot once used Esso, then it started using Total. I don't know, but at the same time Peugeot HDis started having turbo issues. May be a coincidence, may not.

I think the best thing to do would to change to fully synth and change the oil again 1000miles later.

Agreed.

[Archangel]

Isnt Total a french company as well ?

[highlander]

Isnt Total a french company as well ?

Yes. The company name is Total, S.A. (or, in full, it is "Total, Société Anonyme"). They're one of the biggest petrochemical companies in the world, but unlike just about all the others, they have retained their headquarters in France (in a Parisian municipality), rather than shifting over to Dubai.