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Rebuilt head gasket leaking coolant from rear, 4.0 Renix


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I rebuilt the head gasket and got everything installed and working.  I recently noticed a slight coolant leak coming down right at the bell housing, some location if you had a rear main seal oil leak.

 

I finally found it...

 

It's coming from the circle that is pressed into the rear of the head itself, not the head gasket.

 

I found a picture to help show what I'm talking about.

 

CPS%20location.jpg

 

 

Is that from the rebuild and they didn't get a good fit when they pressed it in?

 

I assume there is no way to fix this without pulling the head again?

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So it's the rear freeze plug on the head...  It must have been messed up when rebuilt.

 

I've read you can remove the transmission/transfer case and replace it by tilting the engine, therefore making you not have to redo the head gasket, valve cover gasket, etc...

 

Thoughts?

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You might be able to temporarily slow/stop the leak by draining some coolant, cleaning the heck out of the freeze plug, and applying a generous amount of RTV around the entire OD of the plug.  As rust builds up in the cooling system it might help the cause as well. Saw that happen on OneOverZero's leaky freeze plug.

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I actually had this plug pop out when my block froze... But that's a different story... I managed to get a new one in with a big prybar, and using the pinch weld where the hood mates up as a leverage point. No removal of anything nessicary. I just pressed it in until the lip was fluch with the head surface... Seems good so far ( two years later).

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The head was rebuilt by a good shop, so not sure how they messed it up, it's a new plug in there.  I assume they either didn't clean the surface well enough, didn't press it in far enough, or pressed it in too far...

 

I just got it all running well after a huge job, one part of which was the rebuilt head.

 

I might try the pry bar idea, or just pull the head out.  I see these "expansion plugs" that would work, but those don't seem like they would last very long.

 

I might try to hoist the head up with the intake/exhaust still attached and that will save those new gaskets that are nice and tight after multiple heat cycles and re-torqueing.

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Myself, after all that work, I'd definitely try the expansion plug. FWIW, I've used them with good long term results, especially in a situation like yours where access is difficult. you could always get a mechanic estimate and try chasing a legal recourse for defective product.

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I talked to my friend who put it in and recommended the machine shop, they both will fix it free of charge, but I still lose the car for a few days, have to double check everything, make sure all the wires are run correctly away from manifold, heat cycle and re-torque manifold/intake bolts, blah blah...

 

and it's my daily driver

 

I really think that the machine shop might not have tapped it in far enough and the new freeze plug just needs one more tap...

 

I'm considering trying tomorrow using a 36mm socket and trying the crow bar method to see if I can leverage the firewall and get it to push it just a little bit more.  With my luck though I will push it sideways and then have to tow the car to the shop to get it fixed.

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