On Saturday, I had to travel from Surbiton to Ealing Broadway, a round trip of around 18 miles with a stationary hour of so before returning. It was stop/start and slow moving traffic all the way in both directions.

On the return journey, I noticed that the engine it developed a constant chattering sound, not unlike the tappet sound of the old A series when they're out of clearance. On revving the engine in N, the sound remained, although perhaps not quite as loud as when its under load.

The oil temp was between 103-105c and the water temp was dead centre as usual. The following morning the sound had gone, albeit the trip I did, didn't even get the oil temp beyond 70c.

So it'll have to go in for a check up, but in the meantime, any suggestions?

Maybe related to the wet spark plugs we found? Leaking cam cover sealant…?

Yep, could be Travs.

Did the same trip yesterday. Nothing. Engine sound perfectly normal. Oil temp upto 110c. Weird….