Low compression of about 90psi in one cyclinder. all other cylinders are fine. mechanic thinks it is probably burnt exhaust valve. im not burning any oil and theres no coolant contamination.

firstly, i am only planning on keeping the vehicle for about 2 years and then selling it, so is it worth getting this fixed or should it be fine?

secondly, if i were to get it fixed how much would it cost? i hear these fixes are expensive due tot he labour taking the head off and all that.

cheers!