What the heck- started the KL from cold this afternoon after not being driven since Friday and heard a good 3 or 4 seconds of what sounded like lifter and tappet noise. Idle then hunted a little for a minute or so

It was pretty loud. Never did this before. Was alright after that.

The KH will have some lifter noise on startup after a few days standing, but never heard it this loud in the KL before... And only sitting for a couple of days?
Whats happening?

Are you sure it is not the timing belt tensioner?
From what I understand people often get these confused

Are you sure it is not the timing belt tensioner?
From what I understand people often get these confused
I'm certain. You get this noise sometimes for a second or so on cold start before everything circulates. This went on for about 4 seconds which is a long time imo.

Started and ran flawlessly this morning. About 2c , cars covered in frost and even ice on the windshield but no problems at all then drove beautifully all the way into the city.

As i said, if i leave the KH for a few days standing it will do it too but not usually after only 2 days.

From what I understand these lifters have a spring loaded ball bearing in them that should allow oil in but not out.
If there is loud lifter tick after initial start up from a short period of rest then I'd assume at least one lifter is letting oil out too fast.
I am not sure whether this does damage or not though to be honest.

To give you a comparison, I start my car once every 7-8 days (weekends only) and it does not make any lifter tick at start up. Temperatures are in the mid teens usually and almost 200K.

From what I understand these lifters have a spring loaded ball bearing in them that should allow oil in but not out.
If there is loud lifter tick after initial start up from a short period of rest then I'd assume at least one lifter is letting oil out too fast.
I am not sure whether this does damage or not though to be honest.

To give you a comparison, I start my car once every 7-8 days (weekends only) and it does not make any lifter tick at start up. Temperatures are in the mid teens usually and almost 200K.

Sounds fiiiiiiiiiiiiiiiiiiiiine. As long as it goes away after a bit.

When they're making a loud ticking noise when the engine is warm THAT is when you might want to consider replacing the lifters.

It only decreases the performance a bit from what I can tell. There isn't going to be a massive engine failure, and lifters are actually pretty easy to replace, just gotta have a torque wrench to to the rocker rails but up to the right tension.

Does anyone know the cost of these lifters, and whether aftermarket ones are as good as OEM ones?

This went on for about 4 seconds which is a long time imo.

Nah my 300,000Km+ car would randomly have a horrible rattle for up to 1/2 a minute at idle - it was always the same rocket/tappet, and it didn't seem to make any difference what oil I used 10/40, 20/50 mineral or semi-synthetic.

As I understand it the valves are essentially a hydraulic tappet so it seems there is a slow fill of oil - sounds bad but not terminal.