This would be a good time to replace any hoses associated with the HX, once you have the HX out you may find chafing on them. I installed new hoses and protected them with a section of automotive heater hose wherever the hose contacted the engine. I cut the heater hose into 3-4" pieces then slit the hose lengthwise and slipped it over the coolant hoses, securing them with tyraps. Have a look at the exhaust hose also, mine needed replacing but I would not have noticed with the HX in the way.