I've got to remove the head on our 200TDi.

If I'm lucky a chunk has fallen off the head of one of the valves; if I'm unlucky (according to my ever optimistic father) a piston ring has broken, a gudgeon pin has sheared or worse...

Are there any dodges/problems to be aware of when removing the head? I've successfully overhauled a twin-cam Rover K-series head and given most garages throw up their hands in horror with those (can't really see why), I'm not fazed by the job - just the weather....

Do I really need to remove the bonnet or can I flip it all the way back onto the (suitably padded and protected) windscreen without damaging it?

Is skimming the head a must?

Actually, comments on what the problem might be would be appreciated.

My wife was driving it along the motorway and suddenly lost power accompanied by a loud tapping noise. She called the AA who diagnosed valvetrain issues. When I looked the next day (it still runs), there is a loud tapping accompanied (when standing outside the car) by a hissing noise. I've whipped the valve cover off and removed the glow plugs and turned the engine on the starter and with a spanner on the crank pulley.

I can see nothing amiss (other than two very obviously leaky valve stem seals - two of the glow plugs were soaked in oil). No oil in the coolant or other obvious signs of HGF.

Given the possible cause I'll be removing the head and rebuilding it anyway. How do I diagnose broken piston rings without pulling the sump off, dropping the crank and pulling the pistons out?

Comments most welcome...

Malcolm

Have you done a compression test? That would show you if you had a valve problem and where.
You said there was no oil in the collant, but is there any coolant in the oil? It will be charactarised by whitish sludge under the filler cap and under the rocker cover.
One way of seeing if a piston ring has broken would be to drain the oil and see if you have any metallic floaties.
Are you getting any funny coloured smoke (other than black) out of the exhaust telling you something is getting into the cylinder?

OutbackJack said:

Have you done a compression test? That would show you if you had a valve problem and where.
You said there was no oil in the collant, but is there any coolant in the oil? It will be charactarised by whitish sludge under the filler cap and under the rocker cover.
One way of seeing if a piston ring has broken would be to drain the oil and see if you have any metallic floaties.
Are you getting any funny coloured smoke (other than black) out of the exhaust telling you something is getting into the cylinder?

Click to expand...

Re. the compression test; no, not yet as my compression tester only has adaptors for petrol engine spark plug threads and I can't find a suitable adaptor for the diesel engine in Halfords. Also the oil seeping into 2 bores is surely going to distort results?

Nope, no coolant in the oil (pretty sure there's no HGF).

Smoke was usual minor smokescreen and the same black colour; nothing different. With the broken "summink" I'm a bit reluctant to run it unless totally necessary so it hasn't moved since my investigations.

Thanks for the very useful tip about the piston rings. Will definitely check carefully.

Cheers,

Malcolm