Hi Mark,
Hydraulic lifters have no gap at all, they adjust for no gap by filling with oil.
There’s no damage if it still quietens after a few seconds from cold.
Sludge in a lifter can cause slow fill or leakage and usually clears with clean oil.
I used to adjust hydraulic lifters while idling, back when engines were sitting straight and kept the oil in with the then rocker cover off.
There’s a way to pre-adjust lifters with the engine stopped, but the recipe will have to come from a workshop manual.
I did something like no gap plus half a turn to screw down on those ancient engines.
Dealers everywhere often use 5W40 because it’s Citroen’s expensive synthetic ‘does-it-all’ oil, without considering cheaper oils in warm climates.
An upmarket mineral 15W40 or 15W50 to change every 7 to 10 kkm is more than good enough.
Cheap oils thin out faster and are good for at most 7 kkm.
The timing belt replacement is at 120 kkm on the four cylinder petrol engines … I think.
and has since been reduced to 20 kkm.
