Quote Originally Posted by scarry View Post
This one looks like its a $2.00 part that has caused the issue.
Probably made in China,the part that is.

The other reports are a good read.

Land Rover Defender 90 - long-term review - Report No:5 2022 | Top Gear

Regarding the above. If checking for coolant leaks which would include removing the cap from the coolant reservoir, it would make sense to examine the cap. If coolant was escaping through a crack there would be evidence of coolant where the crack is. Well that's what I would do. I always check the basics first.