Cracked Head

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06-24-2009, 03:32 PM

#16

EvilBlackXJ

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Location: Arkansas

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Year: 1999

Model: Cherokee

Engine: 4.0l

Well, it's my cracked head. sorry if you didn't see the humor.

Lighten up.

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06-24-2009, 10:41 PM

#17

Firestorm500

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Year: 2015, 2012

Model: Grand Cherokee (WK2)

Engine: 3.6L

Quote:

Originally Posted by northline76

Thank god that I havent have them do the work yet, because what happened to you sounds exactly what happened to me. The coolant poured from the back of the head down the engine tranny junction and firewall there.

My only question is, would the blown freeze plug cause low compression? They did a compression test and I was told that they all were low, but uniformly low. I believe they were all around 130 give or take 1 or two.

Firestorm, how hard was it to fix the plug at the back of the head? How much did it cost?

130 PSI compression is not bad at all for a seasoned engine; especially since they are uniform.

If you want to go back with a metal plug as original, expect to pay about $400-500 plus parts/fluids. The head will have to come off as there is not enough clearance from the back of the head to the firewall.

Me head blew the plug completely out of it, therefore there was not metal remnant to remove. Since I had just paid $700 to have head replaced, I was not in a financial position to have it pulled again to replace freeze plug.

Long story short--I bought a 2-2 1/8" expandable rubber plug from O'Reilly's (NAPA also has them). After MUCH trial and error, frustration, pain, and hand cramps, I finally got that puppy in there. Probably took me 14 hours total time over a 1 week period to fix it.

The plug would not go in the hole firmly and fllush with the head. It must do this before and after tightening the nut or it will pop out. You have to do all this by feel; you cannot see it and have little clearance back there.

My secret solution, learned in the School Of Hard Knocks: I took some 240 grit wet-or-dry sandpaper and evenly sanded the round rubber plug a little at a time in the kitchen sink with water running over it. Then I would go to the Jeep and test fit it. After many trial attempts, I could finally get it to go fully into the hole where the washer was flush with the head.
I tightend the nut carefully and slowly until it felt right.

I filled it with coolant and water. Let it sit for a while, feeling for cold water leaks back there. It stayed dry, so I started it and ran it up to temperature. Shut it down, let it set overnight.

Checked again the next morning for leaks. Topped off coolant; drove it.

Seems to be doing fine now.

Total cost in money: $5.00 part, $11.00 coolant