Coolant

RADIATOR CAPS: The XJ-S H.E. has two radiator caps, but only the one on the header tank (left side of the engine compartment) is actually meant to operate as a conventional radiator cap; namely, to control the pressure in the system. The one on the bypass pipe (at the top right of the engine) is really just a place to add coolant, using a standard radiator cap because they're available. If one or both of the caps go bad, they may be replaced with standard coolant-recovery radiator caps.

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