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Head gasket replacement failure

Tiny
WAYNEMERTZ
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  • 1996 JAGUAR XJ40
  • 4.0L
  • 6 CYL
  • 2WD
  • AUTOMATIC
  • 150,000 MILES
My car listed above is a 1994.

I have completed replacing the head gasket and head bolts.
From the kit, I have replaced the valve guide seals and others that I could find along the way to assembly. However, I had a few seals that I could not see where they would go. I checked the head as best I could with a good long straight edge and so no evidence of warpage.

Well, I am still making steam out of the exhaust pipe. The kit and bolts came to over $300.00 and I do not want to go that route again.

Questions: Should I attempt to tighten the head bolts beyond specs?
Should I loosen the bolts and try to re-tighten to specs?
Should I pull the heads again, check for leaks/failed gasket, and reuse the bolts?
Can I add some type of sealant to the head gasket to seal the leak?

The previous gasket showed where the failure occurred, but now I am wondering if there is a crack some place in the block? I did take a good close look at the head for cracks.

I am out of ideas and patience is running thin.

Hope you can help.

Wayne
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Sunday, November 5th, 2017 AT 8:47 AM

9 Replies

Tiny
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Head can be warped or bent and you may not pick that up with a straight edge, also internal cracking. This is tested with a pressure test. I would do a head check, this is a chemical test to see if exhaust gasses are in the cooling system. If so you still have a head problem, do not use stop leak as this will block the radiator as well and you will have a bigger repair bill these products just do not work.
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Monday, November 6th, 2017 AT 4:56 AM
Tiny
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If I am making steam out of the tailpipe, wouldn't that already tell me that I have a leak coming from the head?
Or, does the head check that you are suggesting narrow the leak to the head and not a block problem?
Thanks,

Wayne
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Monday, November 6th, 2017 AT 11:57 AM
Tiny
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A block problem is very rare, I am just saying that these head checks are are a must each time a head is off, you need to get the head off again and get it pressure tested and repair any problems, in 45 years in this industry I have found 2 or 3 cracked blocks, 2 were quite obvious with the head off you could see a fracture and one was suspect after a very heavy accident that damaged an engine mount and I had it magnafluxed which was not cheap but found a fracture.
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Monday, November 6th, 2017 AT 1:52 PM
Tiny
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OK, I understand the fact that I need to get the head pressure tested, but isn't this done with the head on and the car running? A device with colored solution (bluish) connected to the cooling system reservoir will change color to yellow if the exhaust fumes are entering the coolant? Just verifying.
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Monday, November 6th, 2017 AT 4:15 PM
Tiny
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No, that is a cooling system test for exhaust gasses, the head pressure test is done with the head off and with a crack test done will locate the actual damage, the on car test is just a preliminarily test done to confirm whether you do actually have a combustion problem that requires further action.
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Monday, November 6th, 2017 AT 5:00 PM
Tiny
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Is this pressure test something I can do myself or must I take it to a shop to have it done?
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Monday, November 6th, 2017 AT 5:04 PM
Tiny
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A head repair shop will have all the equipment to pressure test and crack test, get them to test it they can straighten as well if bent.
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Monday, November 6th, 2017 AT 11:25 PM
Tiny
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I've torn the engine apart again, had the head tested and milled. Now, the new gasket is coming tomorrow and I am trying to get the block cleaned and ready again. The last time I did this, I filled in small depressions with JB weld and sanded them smooth. Then I put on the gasket and bolted everything in place. My question is this: Should I have applied the gasket before the JB weld set up? Or, would I even had time to do it that way?

Hoping for the best results this time.
Very frustrating.
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Tuesday, December 12th, 2017 AT 6:23 PM
Tiny
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There should be no depressions in the block, and if there was chemical compounds do not do the job. How deep are there depressions? You can get a bit of erosion around the water jacket ports but as long as they do not come near the fire ring, that not a problem. I have never had depressions that needed filling, some blocks require hand rubbing with an oil stone to make sure that they are super clean and flat, so these depressions are something thatis a bit of a concern, these will have to be inspected first hand, I wont be able to see via a pic, can you get a mechanic to inspect this first hand.
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Wednesday, December 13th, 2017 AT 12:36 PM

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