From the Owner's Manual:When checking the coolant level in the overflow tank should the engine be hot or cold?
I've seen it happen enough, despite what the owner's manual says, you really need to remove the pressure cap (only when the engine is cool) and make sure the pressure side of the cooling system is full.From the Owner's Manual:
Engine Coolant Level
The coolant bottle provides a quick visual method for
determining that the antifreeze/coolant level is adequate.
With the engine idling, and warm to normal operating
temperature, the level of the antifreeze/coolant in the
bottle should be between the ranges indicated on the
The radiator normally remains completely full, so there is
not need to remove the radiator cap unless checking for
antifreeze/coolant freeze point or replacing antifreeze/
coolant. Advise your service attendant of this. As long as
the engine operating temperature is satisfactory, the
coolant bottle need only be checked once a month.
Yeah there are typically a "Cold" line and a "Hot" line on the coolant overflow tank if you just want to visually see that.
My XK has "Full" and "Add" lines.Not on my XK just one line. I just had the thermostat housing replaced a week or two ago and want to top things to the line at the right time to insure I still do not have a leak. I am well aware of pressurized system, cutting my may limited mechanical skill as a gas pump jockey in the mid 60's. Yes there was a time only the real MACHO's pumped their own gas. Now NJ is the only place it may still happen that I know of.