XJ6 & XJ12 Series I, II & III 1968-1992

84 XJ6 Compression Check

 
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Old 09-13-2011, 05:19 PM
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Default 84 XJ6 Compression Check

I finally checked the compression in the cylinders today. I knew there were serious problems when four of the six plugs were wet. So, I plugged in the gauge and this is what I got (numbered back to front):

1: 130psi 2:160psi 3:70psi 4:90psi 5:150psi 6:105psi

Add into this the glorious fountain of coolant that was erupting out of the open cylinders, and I would say something needs to be done. I'm hoping it's just a head gasket at this point. The fact that the oil is not milky makes me hope that it blew pretty close to the end of the last time I drove it, and didn't get much chance to mix.

Any interpretations/advice?

Thanks!
 
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Old 09-13-2011, 07:43 PM
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Time to pull the cylinder head for a look-see :-). Head gasket failures are fairly common on the 4.2s.

Cheers
DD
 
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Old 09-13-2011, 10:13 PM
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Yeah, that's the next task. I've neve done a DOHC before, so I'm trying to find a buddy who can help.
 
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Old 09-13-2011, 11:46 PM
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You'll need a couple of small bottle jacks for the job...to force the intake manifold off the cylinder head and to lift the cylinder head off the block.

Cheers
DD
 
 
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