Blown head gasket

[Mollie]

Hi Guys. I'm just new to the forum,obviously, don't know a lot about motors and just looking for advice about my Grand Cherokee 1999 WJ V8 4.7L. I've had the vehicle for around 10 years now with some 270,000 on the clock. It's been very reliable and runs really well. However a while ago I developed a leak in in the head. I was told by my mechanic that this was the case and it's evidenced by the green stuff that leaks from the muffler and out the back. He also indicated to me that it was bad news as far as far as repairs go. I have had several different quotes and they differ by up to around $2/3000. I understand that a lot of it depends on whether it's just the gasket or worst scenario, corrosion. The latter could be the case if it's an alloy head but I'm not sure about that just yet.
The most reasonable quote, about $2,000, I got to repair it involved taking off the head(s) and putting in a gasket kit (?). I was told at the time that the gasket was most likely the problem. Not that uncommon they said.
I've been putting the usual gunk in my radiator and it's still running ok but still loosing fluid. It's a beautiful machine and I know it's just a matter of time running it this way. I can't afford major repairs and was hoping I could get some helpful advice on what to do please?

[Alexski]

Hi Mollie,
This is a very common issue for WJs and the V8s.

The problem is even in working condition and registered your vehicle is currently worth about $3500. The viability of spending $3000 or more on it does not make much financial sense. If the car was worth 10K yes it would be worth fixing.

At any any time you will see them on gumtree "WJ V8 great condition - blown head gasket" $1000 ono..I have purchased 2 jeeps like this for parts for $700 & $800 respectively.

At 270,000km your engine will need a rebuild, if your going to pull it out to do head gaskets you actually need to recondition the heads or put new ones on. With that amount of Kms i'd put new bearings, pistons, rings and gaskets etc. Also if not already done your diffs will need rebuilding soon and also Transmission. The list goes on. The average working life for these Jeeps is about 300,000km or 20 years. Obviously some people have got less some a bit more.

So your options are:
1.) New rebuilt engine, $5500 on ebay and around $1500 labour to fit. Even after you do this With 270,000km your car will still only be worth $3500 resale.

2.) Rebuilt heads on your own engine - around $2-$3k. I Wouldn't do just this as I recon you will be having other engine issues by 300000k.

3.) If your handy DIY rebuild with parts sourced from USA budget about $1500, you will need engine lift and pretty well equipped toolbox. I have done this myself but on my WJ it had only 180,000km on clock.

4.) Source complete 2nd hand engine from wreckers with fitting. Around $2500-$3000.

5.) Buy a new (used) WJ with low kilometres. There are plenty for sale starting at around $2500 registered. I'd be looking for 2004 V8 Limited or Overland <150,000k. Sweet spot on Gumtree for good ones is around $5000-$6000. If you take this option you can move any kit or upgrades from your old Jeep to the new one.

In my opinion unless your willing and capable to do most of the work yourself option 5) is your best bet.

[Classic Boy]

Has it ever been cooked?
If it has replace the heads as they go soft if they have been too hot they are known to drop valve seat inserts.

$2000 is very reasonable I think given the time involved.
If they haven't been too hot the heads will need, removal, striping, cleaning, syncho seating of the valves and seats, checking for cam tunnel straightness and than a very light surface skim then reassembled and then refitted.
The machinist work will cost probably around $500 for two heads. The gasket kit is around $350, and all the work to pull them and re-intalling them.

[Hoobz]

If it's any consolation I well and truly @:;%*+ed tye 4.7 in mine yesterdee

I'm starting a thread on 'All' the options tonight

Maybe follow that thread?

I'm far too deeply invested in mine now to discard 'Dexter' as a project

It's the exact platform I like, so why change?

[ruffy01]

If it has overheated I would NOT just do the head gasket/s.
The 4.7 is known for dropping valve seats after overheating, so gaskets and valve seats at a minimum.
I'm speaking from 1st hand experience unfortunately.

Good luck, cheers,
Ruffy

[silycr]

I just had a set of HO heads rebuilt. Included all exhaust valve seats replaced, new intake and exhaust valves, plus the usual rebuild items and work. $1300 not including replacement hydraulic lifters, which they negated to mention they didn't do anything with. Put the heads on and they're ticking away, so I'd recommend replacing them too, at $240 for all 16. If you do the heads only, it would be a good idea to do the timing set as well. The plastic guides don't take well to being disturbed at high k's. Plus they're a common problem anyway.

At $2k to get the work done and back together running, is a very reasonable quote, assuming they can provide some kind of guarantee. Ie, 5000km without a related issue, although next to no mechanic would be willing to this I'd imagine. Lucky to even find someone willing to work on the Jeep without a 'Jeep Tax'

Another option for heads, are to replace with rebuilt units from the US. There are plenty available for standard 4.7 with required work carried out and pinned valve seats for less than you can get from here, including postage. Warranty would be a sticky item though, plus getting the right head. There are heads with and without EGR, plus some earlier ones that were cast incorrectly and require spacing washers for the Cam Sensor.

[Tyvokka]

I can supply new unused hydraulic lifters got from the states for $200 if you like as I went another way, so surplus to requirement