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Head Gasket 4.7 Writeup

23K views 25 replies 15 participants last post by  LJ_Cool 
#1 ·
Well, I bought this 2004 Special Edition with 54,000 miles, and it looked like it had been treated pretty well. I haven't had much trouble with it, although I had the problems with the wires in the door, and an occasional rough idle. I have accessed this forum many times and found helpful information, so here is my return.

This has been a daily driver, and has seen almost no offroading.
I just passed 115K miles, and the heater core began gurgling. From reading here, I suspected the head gasket, but didn't really see any coolant loss. Nor was there any coolant in the oil. After few days, it started running rough when first started. I suspected that coolant was leaking into a cylinder and causing a misfire until burned off. After about a week, getting worse all the time, it gave a code P0301 Misfire Cyl #1. I let it sit overnight and dropped a small tube into the spark plug hole, and pulled out a thimble full of coolant. Pretty much confirmation of what I suspected. Time to order parts and do some real work on this truck (for the first time: I have been lucky).
I ordered parts from Rock Auto and Quadratec.

Motor vehicle Car Automotive design Personal luxury car Auto part

My dad ran an auto shop and he used to say that if you spilled a gallon of water on a modern engine, a week later a pint would filter out the bottom. I'm a little intimidated because I'm about to go deeper into an auto engine than I ever have before. But I have the service manual and I'd rather do it myself than pay someone.

Hood Motor vehicle Car Vehicle Automotive design

It doesn't take long to get a lot of pieces off this engine. I took lots of photos for help with re-assembly, and I keep the bolts in labeled bags or re thread them into the holes from which they came. Heat was required to remove the cam sprocket bolts, and I used a standard pulley remover to pull the crankshaft pulley. I did not remove the radiator or fan, I could just barely fit my puller in the space that existed.

Automotive tire Motor vehicle Hood Rim Automotive exterior

I bought the special tool for holding the secondary chains, even though I read a forum post from someone who said that you can change head gasket without taking the timing chain cover off. I just couldn't visualize what was in there and so I went with the FSM. I now think that I could do it without removing the Timing Cover.

Vehicle Hood Motor vehicle Car Automotive design

The inside of my engine looks very clean. There is some carbon build up on the piston crowns and on the combustion chambers. I don't see any obvious place where the head gasket has failed.

Automotive tire Wood Auto part Automotive wheel system Machine

Finally I find this spot where it seems that there is a little extra corrosion. I have no idea if this is where the failure lies.

Wood Tool Metal Hardwood Composite material

Bicycle part Tool Wood Metal Auto part

I decided to take a look at my cam chain tensioners. When I touched the bolts with a wrench, the guides broke. They were not very worn and the chains were tight, but the brittleness convinced me I should replace them. That means I spent $80 on the 'special tool' for nothing. I was very nervous about timing the cams, because of a recent post where the OP had grenaded his engine after doing this job.

Automotive fuel system Hood Motor vehicle Automotive tire Automotive lighting

After receiving the heads from the machine shop, I installed them. You can see the contrast between the aluminum head and the iron block here. Also note the angle tool here. I didn't think it would be necessary, but for the 'right' (passenger side) cylinder bank it was crucial. Only $10 at Autozone.

Car Vehicle Motor vehicle Automotive design Automotive fuel system

Re-assembly was quick, although I was slowed by heater core hoses which I had hoped to replace. The dealer wanted $110 and parts houses couldn't find the right part. I re-installed the originals and intend to replace them when I do the heater core. ***EDIT: The correct heater core hoses can be found at parts houses by telling them you have a 2005 model 4.7. ***
Also, I mixed up one bolt between the AC compressor and the generator. That took a while to figure out, but a small hiccup in the overall process.

I was pretty nervous when first starting, and the truck didn't disappoint. It knocked, rattled, and smoked. I thought I must have mis-timed the cams, but the knock quickly went away. I thought it sounded like valves and pistons becoming more than friends; does anyone know what was? It ran fine after that.

In all, I'm glad I did this. Although I was busy at work and needed to ask co-workers for rides during this time, I enjoyed learning about my Jeep. I hope this helps anyone who is facing this project with their Jeep.

I had an IRO 3" lift sitting in my garage waiting to be installed when the head gasket went. I will wait until I trust the engine to install the lift.

Wes
 
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#3 ·
I'd guess the knocking was due to lack of oil and went away after oil came up. I've never dove too deep like that but I know assembly lube is often used when you have an engine opened up like.
I'm sure someone here will be able to add more.
good for you... that's quiet the project.

Well, I bought this 2004 Special Edition with 54,000 miles, and it looked like it had been treated pretty well. I haven't had much trouble with it, although I had the problems with the wires in the door, and an occasional rough idle. I have accessed this forum many times and found helpful information, so here is my return.

This has been a daily driver, and has seen almost no offroading.
I just passed 115K miles, and the heater core began gurgling. From reading here, I suspected the head gasket, but didn't really see any coolant loss. Nor was there any coolant in the oil. After few days, it started running rough when first started. I suspected that coolant was leaking into a cylinder and causing a misfire until burned off. After about a week, getting worse all the time, it gave a code P0301 Misfire Cyl #1. I let it sit overnight and dropped a small tube into the spark plug hole, and pulled out a thimble full of coolant. Pretty much confirmation of what I suspected. Time to order parts and do some real work on this truck (for the first time: I have been lucky).
I ordered parts from Rock Auto and Quadratec.

View attachment 587875
My dad ran an auto shop and he used to say that if you spilled a gallon of water on a modern engine, a week later a pint would filter out the bottom. I'm a little intimidated because I'm about to go deeper into an auto engine than I ever have before. But I have the service manual and I'd rather do it myself than pay someone.

View attachment 587889
It doesn't take long to get a lot of pieces off this engine. I took lots of photos for help with re-assembly, and I keep the bolts in labeled bags or re thread them into the holes from which they came. Heat was required to remove the cam sprocket bolts, and I used a standard pulley remover to pull the crankshaft pulley. I did not remove the radiator or fan, I could just barely fit my puller in the space that existed.

View attachment 587895
I bought the special tool for holding the secondary chains, even though I read a forum post from someone who said that you can change head gasket without taking the timing chain cover off. I just couldn't visualize what was in there and so I went with the FSM. I now think that I could do it without removing the Timing Cover.

View attachment 587905
The inside of my engine looks very clean. There is some carbon build up on the piston crowns and on the combustion chambers. I don't see any obvious place where the head gasket has failed.

View attachment 587915
Finally I find this spot where it seems that there is a little extra corrosion. I have no idea if this is where the failure lies.

View attachment 587918
View attachment 587919
I decided to take a look at my cam chain tensioners. When I touched the bolts with a wrench, the guides broke. They were not very worn and the chains were tight, but the brittleness convinced me I should replace them. That means I spent $80 on the 'special tool' for nothing. I was very nervous about timing the cams, because of a recent post where the OP had grenaded his engine after doing this job.

View attachment 587933
After receiving the heads from the machine shop, I installed them. You can see the contrast between the aluminum head and the iron block here. Also note the angle tool here. I didn't think it would be necessary, but for the 'right' (passenger side) cylinder bank it was crucial. Only $10 at Autozone.

View attachment 587936
Re-assembly was quick, although I was slowed by heater core hoses which I had hoped to replace. The dealer wanted $110 and parts houses couldn't find the right part. I re-installed the originals and intend to replace them when I do the heater core. Also, I mixed up one bolt between the AC compressor and the generator. That took a while to figure out, but a small hiccup in the overall process.

I was pretty nervous when first starting, and the truck didn't disappoint. It knocked, rattled, and smoked. I thought I must have mis-timed the cams, but the knock quickly went away. I thought it sounded like valves and pistons becoming more than friends; does anyone know what was? It ran fine after that.

In all, I'm glad I did this. Although I was busy at work and needed to ask co-workers for rides during this time, I enjoyed learning about my Jeep. I hope this helps anyone who is facing this project with their Jeep.

I had an IRO 3" lift sitting in my garage waiting to be installed when the head gasket went. I will wait until I trust the engine to install the lift.

Wes
 
#5 ·
Thanks.
As of now, I've got about a hundred miles on it and it's running fine.
I believe that the knocking sound was probably the hydraulic lash adjusters filling with oil. Not sure if I could have avoided it by spinning the engine with an air wrench or the starter and plugs out to allow the oil pump to precharge the top end without the compression resistance. Haha, next time?

As for complications, after the knocking stopped, it idled smoothly and I cycled it on and off for awhile, to let the oil I spilled on the exhaust to burn off without catching fire. I'm sure there's a better way. At one point, it began to idle rough and I could hear a rattling sound coming from the top of the passenger side head (near the oil fill port). I thought it was noise from the secondary chain, and spent some time trying to confirm it. At some point, I remember that the PCV had broken in half during disassembly, and I had put in a new one. I started looking at it and realized that it was vibrating. At this point, the Check Engine Light came on and the code was 0171 Bank #1 Lean. Perhaps the PCV was letting too much air in (vacuum leak). I think the PCV was not sealing into its socket, so I oiled the o-ring and it's been fine since. The code has not returned.

Also, the FSM directs you to put black RTV on the timing chain cover during assembly, but there hadn't been any on the gasket I removed (I'm sure this engine is factory stock). The gasket is actually a very thick steel piece with a large rubber strip, and I didn't think RTV would be necessary, so I didn't use it. I was worried that the engine would leak coolant, but none so far.

Also, it's worth noting that the cam timing procedure is pretty easy on this engine. The sprockets and chains have a system of dots, symbols, and colored links that makes it easy to see that you have the timing correct. Getting the three chains in the engine is like wrestling oily snakes, but certainly doable.

In addition, several other posters removed the front clip and radiator, along with the odd hydraulic cooling fan. I was able to complete the job without removing any of that and used a standard puller to get the crank pulley off. I just put a socket on the crankshaft, greased it on the inside, and let the puller push on that. I should have taken a photo of that.
 
#8 ·
Awsome write up man, thx for sharing :)
It might help me alittle as well, i am about to replace a leaky intake manifold gasket
 
#9 ·
Congratulations and well done... I have been working for a shop and the other two guys with over 40 years experience won't touch those jobs. how long did it take? I know you said you had to get rides home so Im guessing it was over a period of time
 
#10 ·
Hey, I'm just glad that I can give back a little to the forum. It sure has helped me out a few times!

I installed the pulley by just torquing down on the bolt, as I had read a few other posts from guys who had done that with no issue. The only special tool I had was the cam chain holder (wasn't necessary) and the angle torque tool (absolutely necessary).

It took me a couple weeks of evenings. I was working a lot of hours at my job, and also had a vicious cold at the time. I'm not sure how many hours I spent on this task overall, but it was quite a few, because it was my first time doing it and I was trying to keep myself slowed down, taking lots of photos, bagging every bolt that came out, being careful with wire looms, and of course many hours fighting the exhaust bolts!

I'm surprised that experienced mechanics wouldn't want to do this type of job. Seems like it would pay quite a few hours.
 
#11 ·
It pays well but if it's busy it will take up a bay for however long till it's done. We only have three bays so that might have something to do with it... it took me a week trying to throw in a new radiator while keeping up with everything else, should have only taken three hours or so.
 
#13 ·
Thank you for the great write up. Now I know that head gasket replacement is a feasible DIY project. Around the first of this year, the head gasket on my 2003 4.7 WJ blew in a big way - big cloud of water vapor and no power. I had my Jeep towed to my house to figure out what to do. I got repair quotes up to $2,000.00! At the time, I didn't think I could handle the job but, thanks to you, now I can handle it.

In desperation, I tried "K&W Nanotechnology Head Gasket & Block Repair" exactly according to the instructions.
http://www.jeepforum.com/forum/f310/k-w-nanotechnology-head-gasket-block-repair-1976474/
and
http://www.jeepforum.com/forum/f310/update-k-w-head-gasket-repair-stuff-2087593/

The darned stuff worked! I put it in over 8 months ago and absolutely no problems. However, I realize that someday I'll be putting in new head gaskets and your write up was a big help.
 
#14 ·
Ran into a bit of a problem. A lot of local mechanics are telling me that the timing chain is a pain in the anus. They all claimed it required a special tool they didn't have. According to this writeup you just line everything up, and painting it doesn't hurt.

Also I do remember seeing someone that didn't remove the timing cover and just use zip ties to hold them in place. Can't find the link. I found one link but not a lot of visual aid.
 
#15 ·
The timing chain tool is required if you remove the timing chain cover, which is the way the FSM requires. Some have said that they did the job without removing the timing chain cover. If you can do this, it would save a lot of work.
I followed the FSM method, but then I just went ahead and replaced the timing chain slider blocks and tensioners, and therefore I had to retime the engine making the special tool a waste of money. It was very straightforward to time the engine, and since my engine seems to have been extremely clean but still had bad slider blocks and one failed tensioner, I would have to recommend doing it that way. IE; remove the timing chain cover, pull the gears and chains and inspect slider blocks and tensioners, then retime the engine upon reassembly.

The two things on this job that were actually a 'pain in the anus' were the exhaust pipe bolts and all the bolts on the passenger side aft end cylinder head.

I've got about 17K miles on the engine since doing the head gaskets (132K total), and it still runs like a top. Ran it to redline today, as a matter of fact.

For those who are going to do the job, make sure you take lots of photos! I took over a hundred pictures and used them all for reassembly, and several times I wished I had taken a couple more detail shots!
 
#17 ·
2004 Head Gasket Leak

Wes,
Thank you for taking time to chronicle your experience. I had a very similar problem, and your summary was very helpful. My 2004 Jeep also had the HO V8 and had about 150k miles. Noticed a misfire on start-up, but it went away after about 5 seconds. Replaced plugs, the coil pack and injector with no effect, before I realized that the exhaust was also pretty steamy immediately after a start. At that point I looked online to see if this engine had any issues with head cracking or head gasket leaks. When I found your article, it all come together. Looked like a fairly involved project. My engine also had the problem in cylinder No. 1, so I figured that there must be a less stiff area in the head deck that reduced clamping locally. Since you had difficulty telling where the leak was occurring, I figured it might be worth considering some type of stop leak. The fact that the leak was pretty minor suggested that if stop were to ever work, this should be a good application. There were also follow-up comments on your original thread that suggested different stop leak products. After some research of reviews, I got a bottle of K&W Nanotechnology Head Gasket and Block repair. I flushed the cooling system until there was no taste of glycol present, installed the fluid, and let the engine idle for an hour. I then drained the cooling system, and applied some low air pressure to completely purge any water. The next day I refilled the system with new coolant, and carefully purged any air. There were no bubbles in the cooling system. The next day when I started the car, it ran fine. After a couple short trips, confidence increased. I did remove the valve cover and checked head bolt torque, and found everything within spec. Next we ran a real test. We drove the car from Iowa to Boston and back, putting 3000 miles on the car. Although we had decent confidence in the fix, I did pack a bottle of coolant. We made it back and all is well. Pretty much ready to consider it a permanent fix. Always a little skeptical of fixes in a bottle, but there are situations where they can work. A good product can plug a pinhole leak if there are no underlying issues. I suspect that there might be a thin spot in the head deck that allowed the gasket fret enough to produce a small leak. This is totally speculation on my part, but something is causing this problem to occur. In my opinion the stop leak solution is worth trying provided the leak is very small. Thanks again for your post.

Carl
 
#19 ·
My Water pump self destructed and I didn't catch it in time, plus it was foggy and rainy, and I couldn't see all the Coolant steam, so I'm replacing head gaskets. (i'm going to try the method without taking the timing cover off, at first :) )

It didn't look like you dropped your motor mounts to get the heads out. or did you?

BTW, there was a thread with pics on a Durango forum, sorry no link.

Best
 
#20 ·
The tool to hold the chains isn't a necessity, it can be achieved with a bungee cord. Search "4.7 V8 general parts info" here on the forum. When I did my passenger head gasket I used a bungee to hold the chain in position. Word of advice, if you're going to open it up that much at a minimum please replace you chain guides. As the OP said they may look thick enough, but they will be beyond brittle due to the heating and cooling cycles. I did mine and it only took an extra 30 mins.
 
#21 ·
I did not do anything with the motor mounts, although in retrospect, that may have made the exhaust bolts easier to deal with.

As stated above, it's probably worth it to replace the chain guides. It was not difficult to retime the cams, and my guides looked perfect but fell apart the instant I put a socket on the hold down bolts. Those pieces can fall directly to the oil pan.

Good luck!
 
#22 ·
well, just putting the socket on one of the chain guides caused it to break, so I think it will be a requirement to pull the timing cover at least now.

I don't see how one could change the guides with out doing so.

what's the best way to get those heater hoses off?

Thx much
 
#23 ·
I am in the middle of doing this as well but nearing completion. First, unless you use the wedge tool to keep substantial pressure on the chain guides the tensioner(s) will over-extend. There is a procedure to reset them using a vise (check the manual). If you don't reset them they remain at full extension and the chain guides will wear very quickly and you will be doing it all again at some point. To reset them you have to remove the timing cover. If you use an air ratchet it isn't all that bad to do but pulling the vibration damper can be a PITA. Second, it is easy to remove the head with the exhaust manifold attached. You just have to jack up, and from underneath the jeep, remove the two bolts connecting the exhaust pipe to the manifold.
 
#24 ·
thanks, I got a copy of the 2002 fSM, and have decided to pull the timing cover, all the head bolts are loose, now i'm just wondering if I should pull the rockers, and ensure all the valves are up, or just turn the shaft the 15 degrees as stated in the FSM for the left head.

What procedure did you use when lifting the head off?


Tday and relatives got in the way of any substantial progress. I was able to disconnect the Exhaust from the manifolds from below.
 
#25 ·
Just line up all the timing marks like the manual describes and it will be fine. Leave the rockers and cam in the head. Once you remove the cam gear the cam will rotate by itself about 45 deg on the passenger side and 15 deg on the drivers side. Also, use at least two people to keep from marring the bottom of the head. You will need to roll the head a bit for the exhaust manifold to clear the block.
 
#26 ·
This project is going slower than anticipated cause I'm not working on it :-( however, I have the head at the machine shop and will reassemble. of course now I'm worried that I didn't get a new $400 head with new valve seats. I've been told that it will eventual drop a valve seat.
 
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