First , the cause of coolant in the cylinder(s) must be determined , then a realistic assessment of needed repairs can be made. I'm assuming the car is no longer under any kind of warranty for some reason? Also IT IS a supercharged JAGUAR? DEFINE your version of inexpensive for us.......$15G for headgaskets?......The only way to keep from spending an excessive amount of money on it is to find a repair facility that will diagnose it correctly AND fix it right the FIRST time....You have over 50K miles on it?"Jaguar Platinum Coverage" supposed to be standard 5/50 on all XJ sedans?