Blown head gasket 3.7l -help

[Hendrous]

G'day all,
My jeep started running a bit rough over Xmas and then I noticed it was losing coolant. After driving back from the south coast on a hot day I think I've warped a head or hopefully it's just a head gasket gone. No coolant in the oil but I have overpressure in the coolant and it's blowing some white smoke.
I've had it for less than a year and the previous owner had just put a new rad in and now I'm wondering if he might have cooked it up before doing the rad.- and maybe a warped head was plugged with one of those liquid glass additives . Who knows.
Either it's my problem now and I can't really see the point of paying a shop 3k to do the head gaskets only to find I have a cracked head and the costs blow out to what I payed for the Jeep.
I've just spent an hour looking over the forum for a thread on doing the heads on a 3.7l, but I couldn't find a relevant thread..lots on the CRD but nothing much on the petrol engines as far as I can tell.
Can anyone point me in the right direction? Also I'd be grateful for any pointers on what to watch out for when removing and re-installing the heads. Having done a head gasket on a Disco tdi going back a year or two I learned there are things the manuals don't spell out which can trip you up.
In particular I'm wondering about how I handle the timing chain which I've read should be locked in position with some special tool.
Are these special tools essential before tackling this job?
Thanks in advance for any advice.
Chrs

Mark

[Hanna]

G'day Hendrous,

Sorry to hear about your issues mate, it sucks when it happens - I've been there many times....

I don't have a petrol KJ and haven't worked on this engine before, however I have rebuilt and replaced the heads on my 4.7Lt V8 Grand Cherokee due to a blown head gasket a couple of years back. Here is the thread:

http://www.ausjeepforum.com.au/forum...d.php?t=104762

For all intents and purposes the 3.7Lt V6 is the same engine with 2 less cylinders, so most stuff in that thread will assist if you're going to tackle the job yourself. It is a big job and tests your patience at a number of stages, but worthwhile if you buy all your parts from the USA (Rock Auto is great) and have a bit of time on your hands. All the information is in that thread FYI.

If you are able to keep the thing off the road for a couple of weeks, my advice would be to pull the heads off, take them to a reputable engine/cylinder head specialist and have them crack/pressure tested and checked for straightness and hardness. Then you will know if it's worth fixing it or not. If they are all good, make a list of the parts you need and order online, wait another couple of days for them to arrive and then bang it back together.

You don't need any specialist tools for this job, other than a torque wrench, harmonic balancer puller, fuel line-A/C line disconnecting tool kit ($20 anywhere) and the usual assorted tools and tricks of the (amateur) trade. It's not that hard, just very time consuming and if the KJ petrol engine bay is anything like my wife's CRD, everything will be tight for space and you're probably best removing the radiator and front end of the car to create more room.

Good luck with it, and if you need any more tips let me know.

Cheers,
Hanna

[Hendrous]

Thanks Hanna,
Your suggestion of getting the heads off and tested before buying parts makes a lot of sense.
I guess in the worst case where I have a cracked head, I might change course and get a rebuilt engine. I see the autowarehouse has them for about $3k and I'd just have to bolt everything onto that. As I seem to have a rear end seal problem as well as the blown gasket it might help me kill two or three birds with one stone.

Re the air con pipes and the tool you mentioned, I was hoping I could just unbolt the compressor and sit it somewhere out of the way- seems not. Maybe the 3.7l configuration is a little different to the V8? Can anyone confirm?

Chrs

Mark

[Hanna]

Sorry, I have confused you there - you need that tool kit to remove the fuel line where it connects to the fuel rail. You're supposed to try to bleed off any excess pressure before doing so, but mine was fine after not running for a day before I disconnected it.

On my WJ I didn't need to disconnect the A/C compressor, I just unbolted it and held it up out of the way with occy straps. No need to add $200 to the cost of the job if you can get away with it. I can't tell you if that will work on the KJ though, but it's worth a shot!

[Hendrous]

Thanks for the reply again.
That is what I was hoping I could do with the compressor..
I'm currently waiting on a Haynes manual as the CD workshop manual I have is a pain to follow and lacks the images which I need to figure out what half the steps are about.
At this point I'm thinking the hardest part of this job will be getting the timing chains back on without losing tdc and the cam chain positions..I was hoping to find a utube clip where someone shows the correct way but there are no vids about stripping down this engine from what I can see. If anyone knows of one please send the link.
Chrs
Hendrous

[glend]

Jenko did the head gasket in his V6 and after getting a few quotes he decided to put in a crate engine. He wanted a warranty and didn't have time to screw around with it. Just factor in the swapout labour if your getting someone to do it for you. And if your in NSW you will need to go through the Blue Slip rego process (engine number change) so make sure the new one has a number and write it down and take a photo of the exact location because the inspection guys need to see it.

[Hanna]

Originally Posted by Hendrous

Thanks for the reply again.
That is what I was hoping I could do with the compressor..
I'm currently waiting on a Haynes manual as the CD workshop manual I have is a pain to follow and lacks the images which I need to figure out what half the steps are about.
At this point I'm thinking the hardest part of this job will be getting the timing chains back on without losing tdc and the cam chain positions..I was hoping to find a utube clip where someone shows the correct way but there are no vids about stripping down this engine from what I can see. If anyone knows of one please send the link.
Chrs
Hendrous

I actually wouldn't be too worried about losing the cam timing - I didn't find it too difficult on mine at all. There are plenty of marks to assist.

I remember on mine I had the cam wheel marks facing north along with the crank key way, but then once I applied the spring tension of the cam chain tensioners it appeared to pull the cams out of alignment. After rotating the engine by hand a number of times and then convincing myself that they were a tooth out, I pulled them off and shifted one tooth - it was very obvious at that stage that they were right in the first place!!

I'd say the fact that my chains were a bit stretched and that there is margin for error in both manufacturing and the way the repairer interprets the mark positions, means that it will never look 100% aligned. I'll see if I can dig up some photos of mine aligned if you want? I'm pretty sure they were in my thread, but it looks like they have expired now.

Do any of the websites I linked in that thread have photos?