Got this from another tread, think it is a good read on synthetic oil versus mineral:
And in case you are using the Total 5000 in the vehicles in your signature, well, think it might be flowing worse than a synthetic and the hydro lifters are speaking up.
I would also try esters for a leaky rear main seal.. though I'm still interested to see if the mineral oil helped/reduced the oil drip.
This ester additive is 6-7Euro in Bulgaria, so should not break the bank, there might be a more of a specialized formula for your use case..
Heard of it ? Just bought 4 https://www.mannol.de/products/additives/oil-additives/mannol-ester-additive
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