So, already got an ACE fault that is probably needing a new valve block (already had the valves themselves looked at - new valves / no change and still got the fault).

Anyway, 3 days ago started to hear what is best described as a light 'ticking' from the rear of the engine. Can't really hear it from the engine bay, can hear it in the cabin, and from the leading edge of the front doors.

It's not vehicle road speed related. It speeds up and slows down with engine speed whether stationary, in neutral rolling or under load.

Something I noticed today, when rolling (basically constant speed) or coming to a halt), the ticking slows down and stops prior to the vehicle coming to a halt. Yesterday, the light ticking has 'hardened' slightly. I can't find a schematic to tell me what's on the back of the engine, bar being told that the HPFP is there, and it's belt driven I presume.

I had the LR main dealer look at it yesterday while running a diagnostic on the ACE system (thanks for the £2k plus quote for ACE block, plus hard lines if they break them too). Video feedback is that the ticking is related to the valve block. I'm not convinced.

No warning lamps on the dash, bar the ACE warning. Car is 2017, 51k miles, no warranty, I bought it Approved Used and it's only had OEM parts / servicing (last service was a local independent who has an LR Master Tech running the show).

Any thoughts / similar experiences? And yes, I'm getting the indie to look at it because noises like this are not right.

I've never seen a 494/405 with a faulty ARC block, it's always been wiring...

Typically, the valve block comes with the wiring harness (easier to hide a misdiagnosis ) but should be easy enough to repair

Last edited by Disco_Mikey on Sun Dec 18 2022 1:32pm. Edited 1 time in total

Apparently (according to LR), the oil in the ACE reservoir was / is burnt.

Solenoids from a 2nd hand valve block were tested one by one to replace those on my car, with no benefit. The valves inside the block apparently need the valve block removing, which is what is trying to be avoided due to the risks to the hard lines.