V6 Exhaust valve siezed - now free!

[Philskill]

Are these valves sticking because of the external mechanism, or sticking from build-up inside the exhaust?

[RPSN]

As Jaguar has updated the rear exhaust parts to prevent the exhaust valves failure (parts now include a 'graphite collar' and 'bullet spindle'), I’d think the valves on those cars affected are seizing or partially seizing due to a carbon build-up inside the exhaust. The external mechanism is not helped by the fact it doesn’t move when the valves aren’t opening and closing.

Here’s a good example (not mine)......

[Philskill]

Thanks RPSN, Sounds like it was the 2 hinge points then effectively, graphite collars effectively lubricating the spindle and allowing for some expansion and movement.

[RPSN]

Yep, the hinge points (exhaust valve spindle shaft and bush contact area) are the cause of the problem so the parts were updated to include a 'graphite collar' and 'bullet spindle' which aid with lubrication and movement of the valves.