Radiator Caps

1990 XJ-S and 1991 Classic Collection Coupes (US Spec, 5.3L V12)



Two 16lb Radiator Caps


Radiator Caps age – the seal, the spring – I have always replaced the caps whenever I replace the thermostats.  The topic has been covered in “Experience in a Book” and on the Jag-Lovers site – just use 16lb caps in both locations (like with many other things, the V12 has two caps).  One cap is on the “Header Tank” in the front-left of the engine compartment, and one on the “Coolant Crossover Pipe” in the front-middle of the engine.


Radiator Caps

(Viewed from Left Side)



I went to the local auto parts store for two 16lbs caps - $8.90 for a pair.  Remove and toss the old ones and put on the new ones (make sure the engine is cold when you do this).  If you need to “top off” the coolant, use the filler on the crossover pipe.  Next project…


New 16lb Radiator Cap

(On Header Tank)



Questions/comments: Email me.