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Unread 12-29-2008, 11:51 AM   #1
pzappa
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4.7L Blown Head Gasket

I've got a 2002 WJ V8 4.7 Limited that overheated last week and the mechanic reported coolant in valve #2 with a blown head gasket. I decided i would like to try and tackle this repair myself . I have a few questions:

Should I replace the gaskets for both heads?

I've looked for head gaskets online and have found Felpro gaskets and Gasket Sets. Should I install a complete set? Will a set typically contain gaskets for both left and right head? What else is included in the set?

One other thing that has been bothering me... Before this happened i was hearing a strange gurgling noise in the dash behind the glove compartment while at stop lights. I am guessing this was my heater core making the noise? Is there possibly an issue there?

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Unread 12-29-2008, 12:27 PM   #2
ratmonkey
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only do both if you want the extra work or it overheated really really bad.

get the full top end set, you'll need everything.

water rushing in the heater core is a sign of trapped air in the system, i believe the 4.7 system was a closed loop.
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Unread 12-29-2008, 01:52 PM   #3
pzappa
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Blown Head Gasket

Here's alittle more info on my situation.. It overheated a couple of weeks ago in Atlanta traffic. While trying cross 3 lanes of traffic to get to the shoulder, the traffic suddenly opened up and I was moving at a normal speed with no overheating. Before leaving the office later that day, I added some coolant as it was showing low in the reservoir. 3 or 4 trips later, it overheated again...Only this time it didn't appear low on coolant and was very quick to run hot. I had it towed to a dealer where they diagnosed as a blown head gasket.



From link below is this set for both heads? Seems to be two of everything?

http://www.autopartswarehouse.com/de...HS26157PT.html
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Unread 12-29-2008, 02:56 PM   #4
indept
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YES do both, if 1 blew the other will probably go soon and you'll have to rip most of the stuff off a second time. The stuff you have to remove for 1 head (intake manifold, exhaust manifold, valve cover, rockers & push rods and anything bolted to the front of the head like alternator, ac compressor etc) are the same for both heads, the only additional would be the other side exhaust manifold, valve cover & rockers/pushrods, then unbolt the head.
A head gasket set includes both head gaskets, both valve cover gaskets, intake manifold & exhaust manifold gaskets & valve seals. Check both heads for warpage once you get them off. Aluminum heads like to warp when overheated so if you put a warped head back on with new head gaskets it will develop a leak, if not right away, probably very soon after doing all the work. If it does and you have to tear it down again because of warped heads you will have to get new head gaskets, the others can't be reused even though you just did them, so do it right the first time because it SUCKS BIG TIME having to do it right the second time.
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Unread 12-31-2008, 06:12 AM   #5
pzappa
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Thanks for info.. I'm gonna go ahead and replace both.

Just started the teardown yesterday.. Hopefully all goes smoothly. Anything else I may want to think about servicing while everything is pulled out? It has 120,000 miles.. Thanks again..
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Unread 12-31-2008, 09:19 AM   #6
ratmonkey
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send both heads to a machine shop to be milled and have a valve job and the guides done while they're there.
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Unread 01-10-2009, 07:48 AM   #7
pzappa
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Some progress

Well, I've torn the top half of my engine off now and to the point where the valve covers are off.. I'm hoping to pull the heads out today or tomorrow, but i'm really getting a bit uneasy about touching the timing chain cover, chain, etc.. This is where I am and the last steps before removing heads. Any thing I should watch out for when performing the steps below? Tips? Do I need a puller to remove the crankshaft damper?

--I'm here in the FSM:
(10) Rotate the crankshaft until the damper timing
mark is aligned with TDC indicator mark (Fig.
9).
(11) Verify the V8 mark on the camshaft sprocket
is at the 12 o’clock position (Fig. 11). Rotate the
crankshaft one turn if necessary.
(12) Remove the crankshaft damper. (Refer to 9 -
ENGINE/ENGINE BLOCK/VIBRATION DAMPER -
REMOVAL).
(13) Remove the timing chain cover. (Refer to 9 -
ENGINE/VALVE TIMING/TIMING BELT / CHAIN
COVER(S) - REMOVAL).
(14) Lock the secondary timing chains to the idler
sprocket using Special Tool 8515 (Fig. 10).
NOTE: Mark the secondary timing chain prior to
removal to aid in installation.
(15) Mark the secondary timing chain, one link on
each side of the V8 mark on the camshaft drive gear
(Fig. 11).
(16) Remove the left side secondary chain tensioner.
(Refer to 9 - ENGINE/VALVE TIMING/TIMING
BELT/CHAIN AND SPROCKETS - REMOVAL).
(17) Remove the cylinder head access plug (Fig.
12).
(18) Remove the left side secondary chain guide.
(Refer to 9 - ENGINE/VALVE TIMING/TIMING
BELT/CHAIN AND SPROCKETS - REMOVAL).
(19) Remove the retaining bolt and the camshaft
drive gear.
(20) Remove the cylinder head retaining bolts.
(21) Remove the cylinder head and gasket. Discard
the gasket.
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Unread 01-10-2009, 09:50 AM   #8
keith20mm
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While you have the heads off, remove and clean the radiator fins of bugs (or replace it). If you just clean it, pressure test it in a radiator shop to verify that the end caps and core are good, and that the petcock mounting is good. Also inspect the hoses, both main and heater.

Upon refill, be sure to open the hex keyed plug and bleed out all the air, good.
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Unread 01-11-2009, 04:44 PM   #9
pzappa
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thanks keith, probaly will get the radiator checked out while everything is unbolted.

I was working on rotating the crank to TDC today. I rotated it clockwise and passed TDC, so pulled it back counterclockwise then clockwise.. I did this a few times before getting the TDC mark to lineup. The FSM had no warning against counterclockwise on the crank, but the Haynes manual I have said *never* rotate the crank counterclockwise. So, was it wrong/bad for me to rotate counterclockwise??
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Unread 02-27-2009, 08:26 AM   #10
pzappa
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Still battling with this problem.. I know, it's been almost 2 months. Not much time to work on it except weekend. I've gotten the engine back together, but I have a rough low idle problem. I've checked all my hoses for leaks. Some of my findings.

1. Milky oil deposit on PCV valve. Dipstick is clean. I've cleaned pcv a couple of times and keeps getting this milky oil gum. Is it possible that even after a fresh refill of oil there is still some coolant clearing through the system from the initial head gasket issue? Should I drain oil and refill again?

2. Air intake hose at resonator ( one that leads to breathers ) has no suction.. When engine throttled up, smoke emits from this tube. I read in the FSM it should have suction??

3. I see no leaks

Any input as to what I should be looking for or diagnostic tips? TIA
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Unread 02-24-2010, 01:32 AM   #11
netmonky
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Hi, where did you get the step by step instructions to strip the head ? anyone have this documented or have any you tube vid's ?
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Unread 05-07-2010, 08:19 PM   #12
jeephophile
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Exact Same Issue!

I am having the exact same issue with my wife's 06 Commander with only 60K miles. I have the same engine in my 05 Grand Cherokee and now I am really concerned. I got the 4.7s instead of the Hemi's because of the early Hemi problems.
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Unread 05-08-2010, 06:21 AM   #13
kentman
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Quote:
Originally Posted by jeephophile View Post
I got the 4.7s instead of the Hemi's because of the early Hemi problems.
That sure is ironic. I have one of each. Thus, I am less likely to have a common mode failure, but more likely to have an issue in one or the other.

Both motors seem fine to me. The 5.7L is certainly more complicated. Just as long as you do not overheat, both should be fine.
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Unread 05-10-2010, 09:27 AM   #14
Fety
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NOOB Question: I have an 01 Laredo 4.7 ....L? I have no idea, are there other 4.7s? Anyway, is there any way this overheating problem could have been avoided/prevented? I'd like to know if there's anything I can do to not have this happen to mine. It has 85K miles on it now. Thanks!
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Unread 10-13-2010, 08:07 PM   #15
Andyh
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Service Manual Jeep GC 4.0 & 4.7 V8

Here ya go guys.

Free FMS PDF format, its 64mb so it takes some time to load, when it has loaded, just save a copy on ya computers.

I have the 2003 WJ and think i have just blowen the head gasket due to over heating, im in the porocess of stripping it down and found this manual on a Jeep GC website here in Oz.


Free Factory Service Manual WJ 2001
http://www.rol.ac.psiweb.com/jeep/wj_01/WJ_01.pdf
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