4.0L Cracked Head

2001 TJ ~89K miles 4.0L manual T, AC

I'm loosing coolant (very slowly) dealer says its a cracked head, any one familure with this problem?

Anyone using a aftermarket aluminum head? May solver the casting problem but create a bunch of other problems? Should I replace the exhaust manifold at the same time?

Jim

Reply to
James Hilins
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Cracked heads in the newer 4.0 (>1992) are rare. Did they show you how they came to this assessment? I'd be suspecting a leaky overflow bottle, hose, or pump, before even thinking about a cracked head.

Reply to
DougW

Hi James, Like Doug said, we haven't heard of a cracked four liter heads. Usually that only happens went the engine has badly over heated and boiled all the water out and someone pours cold water back in before it cools, and you can hear it when that happens. The Stealership may have been covering the possibility it was cracked, after finding a clean cylinder. So it may be just a blown gasket. Aluminum heads are nice, but don't waste you money on a Rambler engine.

Reply to
L.W.(Bill) Hughes III

It seems as if no one here has heard about the 0331 head castings and their propensity to crack. I Believe the 01 TJ and every other 99+ 4.0 has this head casting, I may be wrong but the Cherokee and ZJ do and there's plenty of XJ owners on naxja.com (a bunch of XJ enthusiasts) who have seen this cracked head.

The Aluminum 4.0 head is made by HESCO, they are DAMN proud of it, to the tune of nearly $2000 dollars proud. Which is something like 19x the cost of a stock completely re-manufactured head. This diamond encrusted Aluminum head only shaves 30 pounds, and does not flow significantly better than the good stock castings that don't crack (castings 0630 and

7120).

I say it doesn't flow significantly better because HESCO will not show actual Dyno sheets despite claiming they would show them many times. and they claim it's good for 10 to 15 HP more, but I'm betting it's more like 1 to 5 than 10 to 15. The only other advantage to this head is that the pushrod holes have been enlarged to allow pulling lifters and thus changing the cam without taking the head off.

Also of note this head was avialable from summit with a different name, same head. At least HESCO claims it was theirs and someone took a bulk order and tried to rebrand them as "Patriot Aluminum heads" Don't know how true that claim is.

Reply to
Simon Juncal

Over on the Yahoo Stroker list the aluminum head has been much discussed, and the conclusion over there was that Patriot is the OEM and Hesco and others are rebranding them. Who knows. The value for a 4.6 is cooler running for higher CR. No need on a stock engine.

Reply to
jeff

There's a stroker yahoo group? I guess I should have figured, there's a lot of stroker owners on Naxja too naturally enough. Can you post the URL?

Anyway I wouldn't be surprised to learn that neither Hesco or Patriot make that head. I just know it's too spendy to put in my XJ :)

Reply to
Simon Juncal

James,

I had the same problem, only at 20Kmiles. Cracked head was the last thing my dealer said, it was the first thing my private mechanic said.

Long story short, 5 visits hot air blown up my ass and some screaming at the dealership and the Cracked head was replaced under warrantee. I have not had an issue since. When i was looking into the issue, i had a 50 50 response. That head never cracks / that head cracks all the time.

I had the same coolant problem. about a reseviour full every 1000 miles. No leaks, no smoke, no foamy oil

Good luck on yours

Reply to
John

Reply to
John

Reply to
jeff

The people saying it never cracks are probably thinking of all the earlier heads for the 4.0 which never crack.

Reply to
Simon Juncal

Count me in that bunch. Had to do some reading to find out what they did to change the head design. I knew they changed the intake, but for some reason I never picked up on the head changing.

Reply to
DougW

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