Range Rover P38 Thermostat testing

Here is a Range Rover thermostat from a 4.6 V8.
It suddenly began to overheat whilst driving. It appeared to have a noticeable leak from the water pump hose.
This was replaced with a new part. It proved to be problematic to bleed the air from the coolant system and continued to throw the coolant out the header tank. They are notoriously difficult cars to bleed, especially when an LPG system is fitted.
After several failed attempts using various methods I decided to inspect the thermostat.
As you can see in the video it’s in very poor condition, the coolant system most likely neglected over the years (possible weak mix/wrong spec antifreeze used).
I placed a good working thermostat along side the old one. It’s a bit of an extreme example using water off the boil out the kettle but demonstrates nonetheless wether it is in working order or not.
It appears that it was faulty and most likely source of the original overheating issue, build up of pressure and the cause of this pipe to burst.

[@cav4290]

Best to replace these everything 5 years, regardless if working or not. Another tip to help with bleeding/cooling is to drill a small hole in the metal housing of the thermostat.

[@Doco72]

Interesting...