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foreman00081 05-21-2007 01:03 PM

4.0 overheating, need some advice on heads please
hey guys, first of all great looking forum! im new to wranglers, had a couple grands back in the day but heres the situation im looking for some help on. my buddy just bought an 01 jeep wrangler 4.0L 6 cyl from a friend of his who said it blew up, he thought it blew the head gasket cause it was smoking badly, leaking coolant and overheating. so my buddy bought it from him for only $1500 with only 74K on the truck and the trucks in great shape except some body dents and bashed up bumpers, no big deal there. so we tore into it saturday thinking it was the head gasket only to find out that it probably only was the waterpump cause there wasnt coolant in the oil and there didnt appear to be any oil in the coolant. well we had it all torn down and already had all of the parts so we figured we would do the headgasket anyways. so my question is that if the head gasket wasnt the problem can i check the flatness of the head at home (i can grab a dial indicator from work today if that would help or a straight edge and feeler gage) and do we absolutly have to have it machined to assure that its flat or can we get away with just replacing the gasket? and the only reason i ask is that its a cast iron head on a cast block so i am thinking that it would be a lot harder to warp than an aluminum head on a cast block and the guy he bought it from only drove it home a very short distance and parked it after it started smoking so it never really overheated much. so if anybody could help me out with this it would be much appreciated and sorry for the long arse post.

and the reason im thinking its the waterpump is that before we tore it down it did run pretty smooth but was blowing coolant out from behind the fan pulley which i thought was coming from the head but found out later is exactly where the weep hole is on the waterpump. also the plugs dont look white like theyve been burning coolant. so does it sound like im on the right track here?
and heres the list of stuff were replacing, if im missing anything let me know please:
head gasket and head studs
thermostat and housing gasket
injector o-rings
throttle body gasket
serpentine belt
water pump and gasket
intake/exhaust manifold gaskets
spark plugs
all radiator and heater hoses
and of course changing oil and flushing coolant system


MOz 05-21-2007 01:22 PM

Use a straight edge to check the head or take it to a shop and have it checked (since you have it off). Assuming it was not the problem, you do not need to have it machined, just clean off the old gasket material, replace with a new one and off you go.

Chances are it did not warp. However, the gasket may have breeched into the combusion chamber and you may not notice coolant in the oil. Take a real good look between the gasket and the cylinder chambers.

Good luck and let us know how you make out.

foxinthemudd 05-21-2007 01:31 PM

sounds like to me that you just need to replace the waterpump and gasket. I had the same problem with a dodge I had, The head did not have any warping. good luck with the problem

richp 05-21-2007 02:08 PM

What is the model number on the head ? happen to be a 331 ?
Check between the #2 valve guides, they tend to crack there. You can usually see the coolant looking down thru the oil filler hole.

foreman00081 05-21-2007 02:29 PM

thanks for the quick replys guys, ive been doing some more reading on the subject and it looks like all signs are pointing twords the waterpump. i wish i had known a little more about waterpumps before we tore it down but oh well at least we will know everythings all good when its back together plus it gives us a chance to degrease the head and the intake manifold and my buddy should have a really nice running truck for under 2 grand! wonder if we should tell the kid that sold it to him that he could have just replaced the $70 water pump instead of dumping his jeep for only $1500!

foreman00081 05-21-2007 02:31 PM


Originally Posted by richp (Post 84120)
What is the model number on the head ? happen to be a 331 ?
Check between the #2 valve guides, they tend to crack there. You can usually see the coolant looking down thru the oil filler hole.

not sure what model it is, ill check that out when i get home

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