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post #1 of 7 Old 06-21-2021, 10:17 AM Thread Starter
Derekwh
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4.0 compatibility

I have a '91 Wrangler with a seized 4.0, would a 4.0 from an '03 Grand Cherokee work as a replacement? I would need to keep the '91 smog equipment to pass California smog.

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post #2 of 7 Old 06-21-2021, 10:24 AM
Randonexplosion
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I'm pretty sure that there are some significant differences in the block on the Grand Cherokee motors like the motor mount bracket locations. I think XJ and TJ blocks are going to be more compatible.


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post #3 of 7 Old 06-21-2021, 11:48 AM Thread Starter
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post #4 of 7 Old 06-22-2021, 01:55 PM
Luuca
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Find a 1991 - 1997 Cherokee 4.0 long block (head and block) in working order. Remove all the accessories like the water pump etc. Install the long block with all your original accessories. FIX whatever cooling issue or other issue(s) you had that seized the block, and you should be good to go.

If you are in So Cal, hit up Inland Jeep for a running long block. Shawn is a good guy there and we have used a few of his motors on projects.

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post #5 of 7 Old 06-22-2021, 07:08 PM
Boojo35
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My knowledge is that there is a significant difference in the block where the AC compressor mounts on 4.0L engines and it matters from the Grand cherokee to the others IIRC. Year of the block may factor in. There may be other differences but this is the big one that I know of.

If you cannot fix it with a hammer then it has to be an electrical problem.
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post #6 of 7 Old 06-23-2021, 09:28 AM
jbolty
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Quote:
Originally Posted by Boojo35 View Post
My knowledge is that there is a significant difference in the block where the AC compressor mounts on 4.0L engines and it matters from the Grand cherokee to the others IIRC. Year of the block may factor in. There may be other differences but this is the big one that I know of.
I have zero experience with this but did they really make a different block casting from the original 4.0 we all know about?

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post #7 of 7 Old 06-23-2021, 11:49 AM
Randonexplosion
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When I was ordering a long block for a 1999 TJ I had to be very specific about the A/C compressor location.


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