Noisy Tappets - Only when warm?

[Riknos]

I changed my oil for Castol fully synthetic 5w30 about 6 months ago / less than 2k miles ago. Now all of a sudden the tappets have started being noisy, but only from a warm start? When I first start it from cold it's fine, but then after a bit of a drive, stopping for a while and starting up again it starts to do it?

[skinny]

it gets too thin when it's hot. change it out for a 10W-40 or something.

[CaptainSlow]

I get the opposite using 10/40, bit tappity when starting from cold then gets quiter when warm.

[skinny]

some engines are a bit fussy on cold start - mine does it too for a few seconds.
sometimes a 0W-40 like mobil 1 can help (as does a costco card so that you can get it for a sensible price!) as it's a little thinner when cold so circulation round the engine improves, but you'll normally still get a few seconds of tapping.