Announcement

Collapse
No announcement yet.

4.0L Head Gasket Replacement

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

  • 4.0L Head Gasket Replacement

    Looks like I may have a blown head gasket. I'll be compression testing this week to confirm, but everything seems to point to that.

    I figure while it's out, a head rebuild is a wise decision, and at $500 bucks for a complete reman head, it seems more cost effective to replace the whole thing than to deck and rebuild what I've got.

    I'm not an engine guy, so this is a first for me. Anyone out there who knows what they're doing wanna come by and lend a hand so I don't have to do this twice?
    - 1988 XJ Base - I don't actually drive it. It just sits in the driveway while I throw parts at it.

    - 1990 XJ Laredo - Old and busted, but it'll get the job done!

    - 1994 XJ Base 2-door - Where'd the other doors go?

    - 1996 XJ Sport - It's red. What else can I say?

    - 1997 XJ Country - My wife wanted something "pretty".

    - 1998 XJ Limited - Cheap and leathery.

  • #2
    I would have no idea what I was doing whatsoever unless seven involves zip ties. I have to head out though I would recommend finding someone that could port and polish it to maybe optimize a bit more horseys.
    2004 Grand Cherokee (WJ), Laredo 4.0
    4.5" Frankenstein Short Arm lift, Rusty ADJ CA's, trussed Waggy 44 Front & 44HD Rear; 315/70:17 Patagonia M/T mounted on Micky Thompson Classic Lock II 17x9

    Comment


    • sjlplat
      sjlplat commented
      Editing a comment
      It actually would be a good time to do a HO intake manifold swap, and I have a few to choose from. As I understand it, you can pull the head with the intake and exhaust manifold attached. If that's true, I could assemble the HO parts and then do a full swap all at once. It all looks relatively straightforward, but I know things always look easier than they really are.

      There is also a valve cover mod for the Renix that I've wanted to do, so I may as well get that done as well.

  • #3
    Well, I did a compression test and I don't see any problems. All cylinders are 120-130psi. No coolant/oil mix, no misfires.

    So far the only problem I have is overheating and what feels like power loss at 60+ mph. Idle and low-rpm temps are rock solid, and the entire cooling system is almost new.

    I'm stumped.
    - 1988 XJ Base - I don't actually drive it. It just sits in the driveway while I throw parts at it.

    - 1990 XJ Laredo - Old and busted, but it'll get the job done!

    - 1994 XJ Base 2-door - Where'd the other doors go?

    - 1996 XJ Sport - It's red. What else can I say?

    - 1997 XJ Country - My wife wanted something "pretty".

    - 1998 XJ Limited - Cheap and leathery.

    Comment


    • #4
      As a last-ditch effort, I did another flush and swapped the radiator with a spare. Still overheating, so I think the last thing I've got to do is replace the head gasket.

      New Fel-Pro gasket set and ARP head bolts are on the way, so either tomorrow or next weekend I'l be pulling the head. Wish me luck!
      - 1988 XJ Base - I don't actually drive it. It just sits in the driveway while I throw parts at it.

      - 1990 XJ Laredo - Old and busted, but it'll get the job done!

      - 1994 XJ Base 2-door - Where'd the other doors go?

      - 1996 XJ Sport - It's red. What else can I say?

      - 1997 XJ Country - My wife wanted something "pretty".

      - 1998 XJ Limited - Cheap and leathery.

      Comment


      • #5
        Any psychiatrists in the house? I might need one when this is done.

        Click image for larger version

Name:	20200719_161915.jpg
Views:	34
Size:	2.56 MB
ID:	12474
        - 1988 XJ Base - I don't actually drive it. It just sits in the driveway while I throw parts at it.

        - 1990 XJ Laredo - Old and busted, but it'll get the job done!

        - 1994 XJ Base 2-door - Where'd the other doors go?

        - 1996 XJ Sport - It's red. What else can I say?

        - 1997 XJ Country - My wife wanted something "pretty".

        - 1998 XJ Limited - Cheap and leathery.

        Comment


        • #6
          Well, the head is off and there appears to be some damage to the gasket at the coolant ports. I don't know if the damage was caused during removal, but it would seem consistent with a gasket blowing coolant into the exhaust or leaking compression into the coolant ports. I guess we'll soon find out if this was the problem!

          Click image for larger version  Name:	20200725_145331_HDR.jpg Views:	1 Size:	2.20 MB ID:	12485Click image for larger version  Name:	image_2658.jpg Views:	4 Size:	2.22 MB ID:	12484
          Attached Files
          Last edited by sjlplat; 07-25-2020, 06:05 PM.
          - 1988 XJ Base - I don't actually drive it. It just sits in the driveway while I throw parts at it.

          - 1990 XJ Laredo - Old and busted, but it'll get the job done!

          - 1994 XJ Base 2-door - Where'd the other doors go?

          - 1996 XJ Sport - It's red. What else can I say?

          - 1997 XJ Country - My wife wanted something "pretty".

          - 1998 XJ Limited - Cheap and leathery.

          Comment


          • #7
            Looks like I've got some work to do! I hope I can figure out how all this goes back together!

            Click image for larger version

Name:	20200806_175915.jpg
Views:	10
Size:	2.07 MB
ID:	12522
            - 1988 XJ Base - I don't actually drive it. It just sits in the driveway while I throw parts at it.

            - 1990 XJ Laredo - Old and busted, but it'll get the job done!

            - 1994 XJ Base 2-door - Where'd the other doors go?

            - 1996 XJ Sport - It's red. What else can I say?

            - 1997 XJ Country - My wife wanted something "pretty".

            - 1998 XJ Limited - Cheap and leathery.

            Comment


            • #8
              Got quite a bit done today. Primed and painted the head, cleaned the rocker arms, installed the new head gasket, installed the head, and installed the valve cover. Intake, exhaust, and accessories are next. From there, I'll change the oil, top off the coolant, and fire it up to see if it explodes.

              Click image for larger version

Name:	20200808_094258.jpg
Views:	5
Size:	2.22 MB
ID:	12530Click image for larger version

Name:	20200808_103623.jpg
Views:	5
Size:	2.01 MB
ID:	12531Click image for larger version

Name:	20200808_133451.jpg
Views:	5
Size:	2.67 MB
ID:	12532Click image for larger version

Name:	20200808_133437.jpg
Views:	5
Size:	2.57 MB
ID:	12533
              - 1988 XJ Base - I don't actually drive it. It just sits in the driveway while I throw parts at it.

              - 1990 XJ Laredo - Old and busted, but it'll get the job done!

              - 1994 XJ Base 2-door - Where'd the other doors go?

              - 1996 XJ Sport - It's red. What else can I say?

              - 1997 XJ Country - My wife wanted something "pretty".

              - 1998 XJ Limited - Cheap and leathery.

              Comment


              • #9
                A few more pictures...

                Click image for larger version

Name:	20200808_193651.jpg
Views:	5
Size:	2.64 MB
ID:	12535
                - 1988 XJ Base - I don't actually drive it. It just sits in the driveway while I throw parts at it.

                - 1990 XJ Laredo - Old and busted, but it'll get the job done!

                - 1994 XJ Base 2-door - Where'd the other doors go?

                - 1996 XJ Sport - It's red. What else can I say?

                - 1997 XJ Country - My wife wanted something "pretty".

                - 1998 XJ Limited - Cheap and leathery.

                Comment


                • #10
                  Looks like the install is going great. I replaced the cylinder head on my TJ in March and know what you are going through. Just love getting to those bottom bolts on the intake/exhaust manifold.
                  2001 TJ 4.0, 32Rh auto tranny, Dana 44 Detroit Truetrac 3.73 rear, Dana 30 Detroit Truetrac 3.73 front, Rancho adjustable lower control arms, 2 inch lift, BFG mud terrain 31/10.50/15 tires

                  Comment


                  • sjlplat
                    sjlplat commented
                    Editing a comment
                    Yes, I'm not looking forward to that! I've read that you can thread them in just a hair and slide the intake manifold on, so I'll try that and see how it goes.

                    I was planning to get things bolted back up this past weekend, but I discovered a small crack in the exhaust manifold. It's not big enough to leak yet, but it will be eventually. I figured I'd replace it with a new one while it's out rather than go through the trouble of pulling it again.
                Working...
                X