The best oil to protect an auxiliary oil pump. (K4M 854 engine)

[ClioWilliams]

Hi,
My engine is known to be reliable. (Renault Twingo RS)

But in my research, I found someone who had a problem with the auxiliary oil pump in the cylinder head cover.

It was on a Renault Mégane II 1.6L 115hp with a rev limiter at 6500rpm.
I don't know how his car was driven, I don't know what oil he used.
I don't think it's a real weak point as I've never seen anything like it on Renault Sport forums with the same 1.6L optimized to 133hp and limited to 7000rpm.

But I'd like to take every precaution.

The mini oil pump is driven by a square cam on the exhaust camshaft. To supply the intake VVT pulley with oil.

And here's what I found:

Could excessively viscous oil in very cold weather stress the cam and its roller tappet ?
Is it better not to use an ACEA C3 (mid saps) oil ? Does ZDDP affect the rollers?
Would an oil with VW505.01 standard (for VAG TDI with pump injectors) be preferable?

I currently use Castrol Edge 0W40 ACEA C3.

Thanks for your help.

 

[Bjornviken]

i would use full saps oil in that engine for sure, but that's me

 

[Jetronic]

Go for an oil with a high zddp to detergent ratio: eg 1000 ppm P to 2500 ppm Ca + Mg over 3000 ppm.

Viscosity is your friend, not your enemy.

And keep the oil CLEAN. it looks like the oil change interval is or has been too long. That varnish in itself is harmless but it's a symptom of much worse

 

[ClioWilliams]

Okay, thank you.

I'll buy an ACEA A3/B4 oil next time, and try to look at an analysis just to be sure.