OIL ISSUE MY SON IS BUYING A 1994 JAG XJ6. CAN ANYONE TELL ME THE TYPE OF OIL AND CAPACITY? THAN YOU.

I have a 94 4.0L and I use 10W-40 in the winter and 20W-50 in the summer. It keeps the pressure up and it doesn't smoke when I start it because of the valve seals. It takes 8 quarts everytime including the filter. 2 gallon jugs. I change it about every 4,000 miles.

8.5 quarts I use 20 w 50 racing oil. my pressure is great!

I have a 1990 and 1992 XJ6. When I used 10W30 I found the oil pressure guage registered very low pressure especially at high air temperatures. As far as I know the same 4.0L engine requires 20W 50 engine oil and not synthetics.
Since using that weight, and that engine needs 8 quarts......, pressure guages read perfectly.