Maintenance for semi high mileage XK 3.7
Just got my XK two weeks ago and finally getting around to doing some maintenance and repairs. With how cheap parts are, do you guys find yourself replacing parts before there is a problem? I'm not talking about the typical oil and spark plug maintenance, but the water pump, thermostat, trans filter, etc... In a nut shell, I'm replacing the passenger valve cover gasket tomorrow (it's leaking). Does it make sense to replace the driver's side at the same time while I have everything off even though it's not leaking? Also should I do the do the spark plugs and replace the camshaft sensor since everything will be off? I can't totally confirm the maintenance record of my XK with 135k miles on it so figure start replacing old parts so I don't have any surprise failures. Any advice would be appreciated.
One other question...I have the full service manual and saw that I need to disconnect heater hoses to get to the valve cover bolts...don't they have coolant running through them? Should I drain the coolant before pulling those hoses?