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.
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.
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.
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.
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.
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.
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.
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.
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
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.
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.
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.
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.
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.
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.
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.
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.
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