Hi Guys,
after changing the thermostat a couple of weeks ago I am now noticing that the thermostat housing is leaking a bit. I am planning to replace the housing but I am wondering if it is mandatory to drain the coolant as I did it before? or it is not mandatory.. I just want to skip this step if not needed. I do not want to get a mess of coolant fluid when I remove the 3 hoses from the thermostat housing.

Thanks in advance, Roberto

 

I am not clear on the subject, but I believe the system is pressurized. You probably do not have to completely drain the system.

For posterity sake, when you change a thermostat, replace the housing, they are notorious for cracking, leaking, and so on. Perhaps a metal replacement might be a good aftermarket piece, I am not available of one besides the OEM one.

 

Adding a new reference with pictures to help others

Reference
LR3 thermostat housing replacement - Defender Source

Enjoy Roberto