Don't dooooooooooooooo it!!!
Actually miller lad, it is a pretty simple job. Just mortal combat to the death between man and Doom-Machine-of-Armageddon at the same time.
First of all.. buy the pieces you will need.
a) Head gaskets - Buy the pair and change the pair. I changed just one once but the other one packed up too. Unless you know which gasket is split, you have to dismantle both anyway... and my replaced gasket was a cheapie and was on the verge of failing again too. So you may as well change the pair and that's "job done" for another 130,000 miles.
Numero uno - the rear gasket - is available from AR. Numero due is "out of production". Luckily, the gaskets are still made by Victor Reinz and you can still find these. The AR gasket has got Victor Reinz printed on it.. so no brainer. VR is good ****. I think I got mine from Highgate Motor Spares (?). VR doesn't list head gaskets for the 155 v6.. but you buy the one for the 1987 GTV6 2.5 ltr and it is identicale.
Don't open the packet in an excited excitement or you'll lose the little bitty sub-gasket that fits round the locating lug (later).
b) Cam belt. You shouldna put the old one back on. Buy a new one. I used AR as they're good for 72,000 miles.. unless you like changing cam-belts.
c) Tensioner. These are made by some Canadian firm and are absolutely first class. My old beast did 2 tours of duty (140k in actual fact) and it was shagged. Blinkin' magnificent performance though. Change yours though.. maybe I was just lucky.
d) Water pump. Yes.. yours will run to 200k but as soon as you decide to leave it, it'll pack up 6 weeks later. Don't mess aboot. New pump is about £80 from Shop-4-parts.
e) Water pump has a wee square gasket on the top as well as the main gasket. If your pump only comes with the main gasket, send me a PM .. I received 10 of the little gaskets and I still have them.
f) Gasketi! Gasketi! Gasketi! Hoooooow many gaskets will you need???
Buy new gaskets for:
i) The chrome pipes where they attach to the inlet blocks x 6
ii) You may want to get new O-rings for the injectors but probably yours are okay.
iii) Oil pump gasket (though AR don't make these any more.. try asking but also be prepared to have a "no longer available" answer. I used Instant Gasket to make a seal.
iv) Rocker cover gaskets - pair
v) Rocker cover - spark plug hole gaskets x 6
vi) Exhaust manifold gaskets x 2
vii) Exhaust header gasket x 2
g) Clips for the injector/fuel hoses as these are single use. Buy a lot of Jubilee clips too, in the different sizes for your cooling system, as I just know yours are rusted and minging. Don't put that **** back in..
h) New spark plugs x 6 (why not?)
i) I recommend very strongly that you buy a crate full of new M6 nuts, bolts and washers. You will remove a lot of old and rusted fasteners. You'll also need some M8 nuts and washers... plus some M6 allen bolts. Different lengths from M6x15mm to M6x25. You will need them all...
Now (unless I forgot something) you're ready to go.
Drain the coolant. Yes probably some smart alex who never did this job will tell you it isn't necessary. I suppose it isn't... but you don't have a 4-post lift and a fully equipped workshop so don't argue. Drain the coolant and remove the radiatore hoses. File the coolant away in a proper container to take to the tip (don't tip it in the drain and don't get any in your mouth = grim death!)
Remove the radiatore. This requires you to loosen off the top valance/slam panel (between the wings) enough to pull the radiator lugs out of the rubber bungs holding it to the bottom rail. You don't have to remove the bumper or the lights etc. Just the 4 bolts, enough to move the slam panel away from the top of the rad, so you can lift it out. You may have to remove the fan first, to lift the rad' out.. but that's a simple one.
Removing the rad.. gives you space (which you WILL need) and also saves it getting mullah'd later. If you like your rad, remove it. I also got the expansion bottle off... it's just in the way and it's no bother to remove it.
Where are we...? Ah yes.. jack the beast up and remove the lower plastic wheel arch in the driver's side front wheel. That lets you see the flywheel. While you're at it, also remove the cam-belt cover so you can see your belt. You'll need a cuppa by now.
Unbolt the TDC sensor.. it's the little doodah (should be stainless steel) next to the flywheel. Trace the lead back to the plug and disconnect it.. Again, saves it getting damaged.
Before you start you MUST set the motore roughly at TDC. The pulley has a groove on it and there's a mark on the head. Rotate the pulley using the nut until it lines up. Don't move the motor from this position.. much.
Unbolt the cam-belt tensioner. That will make the belt go limp and you can (yes you can!) remove it by passing it through a 3mm gap between the pulley and the motore. I've never removed the flywheel pulley and I'm on belt no. 4.
If you're addicted to masochism.. try to remove the flywheel pulley..
Don't worry about marking up the cams or locking them in position.. you can statically re-set it later.
Before you touch the motor.. stuff a cloth inside the "V". You will drop all sorts of nuts bolts washers and tools in there.. and you want them back, I guess.
Remove the fuel rails. First remove all the rubber fuel hoses then the metal bits. There's 2 bolts on each. Undo them and lift them out. Some injectors will come with it, some will stay in the injector block. Pull them all out and put in a sealable bag. Make sure each injector has its O-ring with it (unless you bought new ones). Leave the regulator attached. Don't lose the vacuum pipe.
Remove the clips on the black rubber seals on the shiny pipes. Unbolt the shiny pipes at the fixed end (allen bolts from memory). Start from one end (battery end is best) and rotate the pipe out as you lift it. It should come out easily. The *****-fight is the little allen bolts holding the pipes to the inlet blocks. They will be rusty and just flake to bits.
You should have a nice empty "V" now (check out how much **** is in the bottom of it!
Remove the coil pack. It's attached to the water channel thing on the front head. If all the HT leads are marked vs. the cylinder number they belong to, you can take that right off the car. Saves it getting damaged later.
I'd take the oil pressure sensor off (under the coil) and also can't remember if you have to detach the thermostat... (I think it connects to the water channel thing on the front head) but again, you'll see what's attached to the head when you get this far.
Remove the Inlet manifoldo. That's fairly simple if you ever changed the air filter. Disconnect the clip holding it to the MAF jobbie and unbolt the allen bolts holding it to the rear rocker. Put in a safe place (i.e. your next door neighbour's kid can be de-greasing it and buffing up the brass throttle plate). You have to remove the pipes and wires that connect the oil mist separator and idle control valve and throttle cable etc. but you'll see all that.
Now you should have a bare motor with no clag on it.
I can't remember if the water pump attaches to the heads at all ...if it does remove it now. Otherwise it's easier once the front cylinder bank is out of the way. There's about 12 M6 bolts and it just pulls out (albeit you have 3" of space to pull a 2.9" wide pump through!
Undo the allen bolts holding the rocker covers on. Remove and admire the black unholy mess in your cam gear.. but also isn't it puuurty in there? Remember to adjust the exhaust and inlet tappet clearances .. nobody ever does the rear bank because it's a bee-atch to get the rocker cover off... but you've done it now. Anyways.. that's one for after reassembly.
For the rear bank, remove the oil filler hatch and lift it off (you loosen the nuts and rotate the hatch backwards). Lift out the gear drive gubbins and washer.. don't lose them!!
For each bank, you have to remove the exhaust manifold from the heed. I didn't fancy removing the manifolds so I left them in situ but if you can get the manifold off the head, you're doing well.. so keep on it. Otherwise separate the manifold from the header pipes and leave the manifold attached (but this must be Plan B).
Undo the head bolts. There's 8 on each bank. You only undo the 8 nuts and that's it.
Hahaha! You nearly fell for it!
Now you are properly engaged in mortal combat!. It's you or the Doom-Machine-from-Armageddon now. You have to break the seal of the head gasket and then lift the head off. Sounds easy doesn't it?
If you have the manifolds attached, the front bank will juuuuuuuuuuust about come off. The manifold will interfere with the slam panel but it's loose already (you took the rad' off, yeah?) and it WILL clear. You need someone to help lift the head.. it's all alloy but you have half a ton of manifold attached to it probably. Otherwise, no manifold attached it's a piece of pees.
The rear one....
If you can get the manifold off here you must have wafer thin arms with triple jointed limbs .. or a very clever mechanicking spider monkey. But have a go. Look at the front manifold so you can see how it fits.. 3 nuts and 3 bolts.. probably rusty... but shoooould undo.
Mine didn't... so to get the head off with the manifold attached I had to remove the power steering reservoir and bracket (no big deal) and the cover off the throttle cable junction box (metal box the size of a cellphone on the bulkhead). If you don't know which one it is, it will foul the manifold, so you'll spot it.
If you took the manifold off the head, I don't know if it will foul anything or not.. but anyway.. if anything fouls, remove it, if it doesn't, don't.
Lifting the rear head out needs 3 burly geezers as you're lifting it about 8" to get it off the studs and the more you lift it, the further away from you it goes. I used shock absorber bump stops cut lengthways to put under the head (round the studs) so I could rest the head on it as I lifted it.. but then I removed mine all on my own.... with the manifold still attached (blinkin' well-'ard!).
The oil pump hatch has to be out of the way (you probably have to remove the top engine mount.. forgot to mention it .. sorry!
Anyways.. yeah.. both heads lift about 8 inches until they clear the studs. They will be stiff as the studs aren't all straight.. but just lift it and tug it until they come off.
Now mop up the oil, coolant and mess you have in your cylinders.
Send the heads to the menders. They need checking for being square and skimming.
Remove the head gaskets. Hopefully one will have a spectacular hole in it so you can show your mates later and also prove that it was the gasket wot caused your problem. Take them off. Beware that each bank has a big fibre washer round one of the studs.. the head gasket fits round the outside of it, though your new head gasket might have it integrally moulded.
Also don't lose the locating lugs.. the hollow metal pins. They fit in the block
, after you cleaned the mating surface up.. don't accidentally send them to the menders with the heads or they'll lose them. If they're stuck in the head, take them out and pop them in the hole in the block. Keep them in there with a blob of Blue Hylomar or gasket sealant.. if you lose one... where will you find another?
While you're waiting for your heads to come back.. clean up the mating surfaces. Clean up anything that looks cleanable... particularly in the "v" of the engine. Don't manhandle the fuel rails too much or the legs will distort and then the beast won't fit properly.
Make sure you clean the mating surface on top of the liners.. but don't move or lift the liners at all or you may unseat them from the bottom O-ring holding them in. Be gentle with the liners.. if you knack the O-ring seal, coolant will leak into the sump. But it's not that fragile.. don't be too paranoid. Don't rotate the crank with the head off though or the pistons moving up and down could unseat the liners too. Leave the motor at TDC at all times and don't tooch it!
The head gasket just plops onto the studs. They only fit one way, each one is different and you don't need any jointing compound.
Heads fit back over the studs. Do the rear one first. Plop it on there (lower it carefully.. though it'll probably be tight on the studs.
Tighten the head bolts up to the pattern:
7 1 3 5
6 4 2 8
Bascially you want to start in the middle and work outwards, doing each side equally.
I dunno the torque from memory... but better not to guess! You can find that out..it's the easy bit.
Refit the oil pump and anything you loosened off, then the exhaust/manifold.
Do the front one the same.
Then you just have to reassemle everything the other way round to how you dismantled it..
The cam-timing is fairly straightforward but obviously get the cams rotated to around or near the TDC marks before you fit the heads, so that they're more or less in the right position.. it'll be difficult to turn the camshafts once the head is fitted (pistons at TDC will stop the valves opening).
Put the new belt on round the bottom pulley and then feed it round the cam sprockets front to back. Statically check the cam timing as you do it and when you're done, rotate the engine by hand to make sure it's all tickety boo. Cams and pulley are all marked.. so it's simple.
Check and adjust the valve clearances especially on the rear bank!
Refit the rocker covers with new gaskets and new rocker-spark plug gaskets... I'd also fit new plugs now.. job done for a year..
I think that's aboot it. It'll take you a Very. Long. Time. and you need a lot of space for bits and pieces.. but otherwise it's not complicated... just time consuming. You'll be lucky to get change from £1000 down at the menders though... and you will be impressed with just how nice that v6 motor is as you see how it's built.. (though you won't think so when you're trying to get some rusty old rounded fastener undone!)
Anyways.. if there's something you're stuck on that I didn't mention... just ask.... and good luck!