View Full Version : 4.0 059 Cylinder Head Info

November 1st, 2017, 17:27
Picked up a parts 2000 XJ. Getting ready to pull the engine and looked at the Cylinder Head for casting number. Its marked 059? Never seen that before. Anyone have any info? Thanks

November 1st, 2017, 23:49
If it is the stock head, it's a crack prone 0331.
My 2001 XJ's engine has 125,000 miles on it. The head was off at 95,000 for rebuilding, due to a burnt valve. It was magnafluxed and found to be crack free, so don't assume that your head must have issues.
Do pull the valve cover off and look for a developing crack between number 3 and 4 cylinders.

November 2nd, 2017, 13:35
Thanks for the info, that is why I found this has a casting number of 059. Have had a couple 2000/2001. Wife's has 169k on it still going good with a 0331 Head. Just never seen a 059 casting number, its right where 0331 would be cast in.

November 2nd, 2017, 13:57
Where is the 059 located, that you are seeing?
The casting model number is usually of on the top of the head, just above number 4's exhaust port. I just checked two 0331 heads and pair of 0630s, all had the model number are located there.

November 2nd, 2017, 14:36
If I could figure out how to upload a pic, but its right where the 0331 normally would be.https://scontent-lga3-1.xx.fbcdn.net/v/t1.0-9/23131860_10212466420450055_5748363835095546935_n.j pg?oh=b9eaf3749497f691a05af6ce78c2d846&oe=5AAAF5B2

November 2nd, 2017, 15:16
I'm stumped. A Goggle search found nothing but a Chevy 059 head.
Maybe the block number will provide an clue, if the head wasn't replaced in the past.
Let us know if you find an answer.

November 2nd, 2017, 15:19
The head does not appear to be a stock Jeep head, so it must be some sort of aftermarket replacement. I have seen a similar but unidentified head with a 063 casting number.

Year.......JEEP Casting #

November 2nd, 2017, 16:03
Does it have a coil pack or a conventional distributor and a separate coil?
An 0331 will have the four threaded bosses for the coil pack. None of the earlier head have the bosses.
If it has the bosses, it may be an aftermarket casting.