Thread: Leaking head welch plug & missing manifold studs

Originally Posted by Fluids

BTW - 2 x 8mm studs to remove on the exhuast manifold heat sheild, and the rear one in the turbo heat sheild ... why the **** did they make that 10mm ???? I spent 20min tring to get an 8mm socket on to it ...

I notched my turbo heat shield last time it was off, now I just have to loosen the bolt and lift it off, I didn't have a problem getting a socket onto it, but it was a major PITA to get the bolt started when refitting.

You may also find that more studs let go when you try to remove them, I had 1 snapped and ended up with another 3 sheared.

Originally Posted by SiddersC

I notched my turbo heat shield last time it was off, now I just have to loosen the bolt and lift it off, I didn't have a problem getting a socket onto it, but it was a major PITA to get the bolt started when refitting.

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Brilliant idea ! Thanks. I was wondering about getting the bolt restarted.

I'll add that to the "What else to do while the exhaust manifold's off" thread.



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Hey Kev, if you change to green coolant for December, it would be a lot like Christmas under there

Or you could have ground out the webbing on the manifold at the threaded plug and closest to the lost stud nut. Cut an Allen key to 20 mm long used it with a ring spanner to undo the plug ,,cleaned the plug,, applied some sealant ,,re tightened with Allen key and ring spanner,, put a new nut on the naked stud and hope for the best. All without disturbing the manifold. Did both our D2 TD5's that way 4 years ago and no sign of either leak. Getting rid of that pink crap helped too. Confidently I won't service my Td5's without removing the turbo heat shields first...much more room.

Just spent the weekend replacing my TD5's head gasket. It had been pressurising the coolant system for a few months usually dumping some out of the coolant tank cap overflow but recently also leaking some fluid near the water drain plug you have pictured above. The TD5 has done 226000km and the head has never been off. I found the plastic head dowels partially sheared (about 1mm movement) and evidence of a leak on the turbo side of #3 cylinder. On inspecting the head gasket I suspect that the leak I had seen near the plug could also have come from the coolant gallery adjacent to #3 cylinder. Your leak is much worse than mine was.

I had the exhaust manifold machined flat about 18 months ago when I found broken studs on #1 and #5 cylinders. This time the manifold was flat with no broken studs but one nut on #5 was missing. I have now cut the webs on the manifold and slightly enlarged the holes on #1 and #5 cylinders.

While the head was off and everything was easy to access I cleaned the inlet manifold, fitted a new fuel pressure regulator to head hose (EU3) replaced the alternator with a almost new spare I had lying around and replaced some of the plastic tubing on the wiring looms.

If I were you I would remove the manifold, check that it is flat, cut the webs, fix the studs and reseal the water drain plug (part no LCM100170) with Loctite 243 (blue). If you still have a leak in that area it is probably head gasket time.

Leave the heat shields and engine covers off alltogether. The turbo really isn't close enough to anything to overheat something and the increase in airflow around everything increases immensely dropping temps.


Using Capitals, the difference between helping your Uncle Jack off a horse or helping your uncle jack off a horse...

Originally Posted by BIG O

Or you could have ground out the webbing on the manifold at the threaded plug and closest to the lost stud nut. Cut an Allen key to 20 mm long used it with a ring spanner to undo the plug ,,cleaned the plug,, applied some sealant ,,re tightened with Allen key and ring spanner,, put a new nut on the naked stud and hope for the best. All without disturbing the manifold. Did both our D2 TD5's that way 4 years ago and no sign of either leak. Getting rid of that pink crap helped too. Confidently I won't service my Td5's without removing the turbo heat shields first...much more room.

Thanks BIG O ...

Yeah, I could, but have nothing to grind the webbing in situ, and the leak seems to have ceased (for the moment at least) ... and both the missing studs are sheared off level with the head, so the manifold has to come off eventually, so the welch plug can wait till then.

Good idea about the welch plug though. Thanks!

Originally Posted by gazk

Your leak is much worse than mine was.

If I were you I would remove the manifold, check that it is flat, cut the webs, fix the studs and reseal the water drain plug (part no LCM100170) with Loctite 243 (blue). If you still have a leak in that area it is probably head gasket time.

Thanks Gary ... it looks WAY worse than it actually is ... I know the head gasket is OK. Cooling system doesn't pressurize from exhaust gas, and when the engine cools, the hoses are all soft. It's just the welch plug.

... it's been leaking for over 10,000km, so there's a long term build up of RED, and with a bit of moisture, and the camera flash, it looks catastrophic

It was leaking just by gravity, as the header tank is above the welch plug ... garage floor is dry yesterday & today.

...but yes, the manifold is coming off soon, and I'll do a full once over on the welch plug, manifold, studs, fit the provent, drill exh' manifold for an EGT, change hoses, etc, etc, etc ..... that's alot of etc's