I have an 87 xj that I've recently bought and haven't driven much so I have never filled the tank its leaking so I want to replace it but I don't know what size tank I have does anyone here have a 2.5L and know what size tank I have and or need to buy thanks in advance

 

from what i could Google its a 20 gal tank but stick around maybe some one else can chime in also

 

All XJs (except perhaps the very latest models) came with the same physical size and capacity 20 gal tank. Some were artificially limited to a 13 gal FILL capacity at the factory with internal plumbing restrictions. AMC/Chryco could then charge extra for the 20 gal tank upgrade--just a ripoff.

You likely have a 20 gal fill capacity tank but in any event replacing with a 20 gal tank would present no problems except for the gas gauge reading. The 13 gal tanks can be modified for 20 gal fills but I'm not sure how to do it offhand.

 

87 to 90 20 gallon tank is what you want. As posted above, they're all 20 gallon.