Thread: its time to do the head gasket .

ok all its that time ,need to change the head gasket as im getting the early signs .that is pressure in the tank ,split tank etc. Any tricks ,hazzards or tips for a do it your self job .

Its a long job because of the injection needing to come off.
tips-
1 Mark the position of the dizzy to the timing cover with "white out"or similar. Mark the position of the rotor to the dizzy body. So you can put em back and be sure-er that it will go.
2 I would have the heads shaved 35thou and use OEM "Ehling" 4litre 10 hole composite gaskets. It doesn't matter about the outer bolts,as you have to leave them out because there are no holes in the gasket.
I had teflon seals fitted to my inlets only. This will reduce oil consumption.

3 Have the heads serviced when they are shaved. It only costs a couple of hundred if the guides are OK,which is highly probable.

4 Look at the cam and lifters. Any pitting or discolouration on the lobes means a new cam, chain and lifters. Its much easier to do it with the valley gasket already off.

5 Use a steel valley gasket, as the composites have a habit of dropping the composite material into the valley.
6 I use Hylomar spray on gasket goo on both sides of the valley gasket wher eit meets the ports and inlet manifold, and a double coating around the water passages in each end of the manifold.
7 The valley gasket has a front which unsurprisingly is marked "Front". Put it to the front.
8 The rear head bolts are a Bitch to get at. I reused mine . I used Holden stud thread sealant when reassembling. The sealant is not to seal , as all stud holes are "blind" It is to stop the bolts corroding into the head.
Make sure to clean all the holes thoroughly, and make sure there is no water in any hole. You will find water around the back of the block. I suggest that you lower the level with a syringe or similar so there is no possibility of water in the head bolt holes.
Good luck and don't skin too many knuckles.
Regards Philip A

sounds like a fun weekend ?? ok thanks Phill . ill give it a go .

I have been told that a loose linner in the engine can cause this issue to ,is that right ? and how likely is it to happen to a 3.9

I have been told that a loose linner in the engine can cause this issue to ,is that right ? and how likely is it to happen to a 3.9

VERY. The 3.9s are notorious in UK for slipping liners, but somehow in Australia they do not have the same reputation, probably because the 4.6 is seen as much worse. The 3.9 problem caused LR to xray every block and grade them for 4.0 and 4.6.
But it should only happen if the car is badly overheated, although it can do it just by itself.
Look on the bright side at present, but maybe pull the plugs and see if any look much cleaner and /or different to the rest.
If a centre plug ie 2 or 3 or 6 or 7 look steam cleaned then you should suspect a liner as there are no water passages near the centre cylinders, all the water goes through slots at the very ends of the heads.

Of course 1,4,5,8 also can slip, but if any of these are steam cleaned then you do not know whether it is gasket or liner. A compression test may indicate low compression on one cylinder , as low compression ( on 1,4,5,8) would be more likely to be a gasket than a liner, but not always.
Regards Philip A

get a pressure check done on the system, as the tanks can split regardless of whether there is an issue with the gasket/liners

oh well bit the bullet yesterday and started pulling the 3.9 to bits , have the injection system off ( a good two hours ) but nothing worrying so far . while its apart ill do injectors and the injector rubbers and all the hoses that you just cant get at with it all together .will remove heads after work .everything looks ok in that part of things ,a little oil in the rams but seems ok ! any thing i should replace while im in there ?

How is it going?
Just spray the rams with carby cleaner. Clean out the throttle body with carby cleaner and a rag, Clean out the hose stub from the oil vent. Clean out the Stepper housing and Stepper. Check that all hoses are OK.

Check the "T' piece in the oil vent line which has a small hose into the Plenum. If you break it you need a special part, as the T has a restrictor to the plenum.
Regards Philip A

all is ok , having dramas with the pasenger side head . you need to remove the alternator bracket to get at the front head bolt , ???? strange that . anyway the heads are of and no real drama getting to this stage . they look ok and are currently being shaved which give me time to clean all the other stuff up and replace every thing that i can . the cylinders and sleeves look good unlike the shed floor . my misses is not happy !!. tip for others ,wipe feet before walking from shed to living room .