27th Sep 2017, 17:40
I just drove my XJ6 from Delray Beach Florida to Salinas California towing a small UHaul cargo trailer in 4 days. 3100 trouble free miles and 19.9 MPG - but when I arrived, I found my tyre gauge was faulty and the tyres were 4lbs low, so with the correct pressure, I would expect 20+.
I do have some useful information regarding what sounds like a belt squealing. My car turned 100K miles in Oklahoma and like many others, I heard the dreaded squealing associated with belts or bearings from the front of the engine. Nothing sounded wrong through my stethoscope, but I replaced the water pump anyway as it had a small amount of bearing play and would need replacing soon. Also I replaced the accessory belt (A/C) tension pulley. At $18 it is cheap insurance. The squealing and chirping was sadly neither belts nor bearings though.
The harmonic balancer is a known XJ6 issue in that it "delaminates". The easy test I read about on an XJ6 forum worked handsomely. Using white paint or "white out", mark the toothed sprocket, the 5 groove serpentine belt pulley and the accessory 4 groove pulley on the shoulders (not the belt grooves) in a straight line. Run the engine and let it squeal, then turn it off and inspect the marks. If they no longer line up, the harmonic balancer probably needs replacing. I bought a new aftermarket unit with warranty for $300, as eBay used balancers are too much of a risk I feel. Wholesale Parts Express in Fort Lauderdale have them and many other harder to find parts and their service is good. Just an FYI.
I expect an older car to have issues and the XJ6 is no exception, but the value for money, comfort, performance and looks just makes it a labour of love. The X300 (95-97) to me, represents the Sophia Loren of cars. If that requires explanation, respectfully - buy a Lexus!