The head Gasket?

Hi all, my missus disco 300tdi is acting funny, and has been since we got it last summer. but now its really worrying us. The engine has always sounded very "clicky" compared to mine, and it doesn't have as much grunt either. But now it seems to be leaking from the next joint down from the rocker cover gasket. Rocker cover gasket was changed while back, and I did the tappets at the same time, so their good. Also the water is disappearing every 2 weeks or so. No obvious leaks. The heater will blow cold, then I top up the water, clear the air lock, and its fine. The water in the expansion tank seems to have a tiny amount of oil on top, but doesn't get any worse, and no water in the oil. So what do ya think? Is it the head gasket, or just a LR injin at its best? Help please!

i would think you probably need to change head gasket and manifold gasket either may well be your clicky noise its rare for them to put water in the sump as some engines ,check rad is hot all over core surface as inefficient cooling from rad often ius cause of head gasket although yours is probably down to age ,there is a block drain bung half way up block just in front of turbo (13mm socket )undo and drain before removing head,you would need err5263 head gasket err3785 manifold gasket and head bolt set at the least or you can get head gasket and stc2802 gasket kit if you want to remove injectors ,replace valve stem seals etc but its not necessary if you just want to do head gasket,

Thanks, would it be worth my time doing the valve stem seals at the same time? We plan on keeping the cars forever, so I want to keep the best I can. Also is it hard to do a head gasket? I've got most tools now, and a bit of common sense. Did a search but mostly people talking after they'd done it, now doing it.

if your keeping it ,do seals number valves to keep in right order ,i would give them a light lapping in too ,kits are cheap from motor factors ,its quite an easy job as you dont need to disturb timing assembly or remove rad etc ,turbo when undone can be held away enough if you have someone to help you when removing head so doesnt need fully removing , its worth getting head gasket and kit as well as 2 x etc8352 dowels ,the 2 rear most bolts cant be removed or refitted with head in place so use a magnet etc to hold bolts up so the dont protrude through head while refitting head,when tightening bolts down first 40nm second and 3rd are 60 degrees which if you mark head and bolt is one flat of bolt which is easier than angle guage 4th is 20 degrees on 10 bolts around cylinders only

Cheers for your response. This is starting to sound rather daunting... Is this doable for a monkey? I'm up for it, but is it something you just need to take your time and think with, or is it a job where you really should know what you'r doing?

its very doable ,setting the tappets is perhaps the most complicated bit

Really?!? Oh well that settles it then. Tally ho! Cheers for the help James. Your a star!