Blown Exhaust manifold gasket

[nick_dawson]

I suspect that the exhaust manifold gasket has failed as I'm getting a horrible screeching noise under load.
What's the best course of action? Helicoiling seems a good idea if any of the bolts have pulled out of the head, but if the bolt has simply snapped then is it necessary? Also some people advocate removing the webbing between the branches of the manifold. This seems like a good idea as it should reduce any shear stresses on the bolts, but is more likely to allow the manifold itself to crack and presumably LR put it there for a reason.
What are peoples experiences of this?
thanks,
Nick

[wy111]

Screeching under load? Sure it's not the alternator or auxilliary belt. Have you had a look under the lid to see any manifold problems or is there something you've done and haven't mentioned. Also what model is it?

[nick_dawson]

Confirmed it today by removing the turbo heat shield and its sheared a bolt on the manifold. Unfortunately it looks like it has sheared off flush with the block, so could be fun to remove. :(:(
Its an 04 TD5, and from reading around on different forums it seems like quite a common problem. :rolleyes:
What have other people done that has worked successfully to stop it reoccuring though??
Nick

[JimAttrill]

Yes, the TD5 manifolds warp and pull or break the studs especially at cyls 1 and 5.

To get the stud out, I know this sounds crazy, but we use a left-handed 6mm drill. Not easy to find, and expensive, but often avoids the tribulations of the eezy-outs which break off etc. You need a drill that goes backwards, of course.

The other way is to put a nut over the stud and weld it on. This is normally the easiest method.

Put the manifold on a sheet of glass and you will normally find it is warped. Get it skimmed which will help in the future. Then drill the holes out to 9 or 10mm which also helps. You can also remove the webs between the pipes, some have found this works.

And we also replace ALL the studs with Würth Mercedes-Benz studs which are exactly the same size (8x35mm) but don't break. We also use Würth locking nuts. Copper-plated and look quite pretty with it.

And if you are feeling rich, get the manifold ceramic coated which cuts the heat down amazingly.

As you can see, we get plenty of practice at this :D

[nick_dawson]

And if you are feeling rich, get the manifold ceramic coated which cuts the heat down amazingly.

As you can see, we get plenty of practice at this :D:confused:

What, on the inside or the outside? If you coated the outside I'd have thought that the manifold would get hotter?? Better for turbo pressure, but would cook the manifold even quicker?!?!

I guess that with the climate you have there, you come across heat related problems more regularly than in our 'temperate' climate. :rolleyes:

regards,
Nick.

[JimAttrill]

The inside and the outside are coated - the manifold runs appreciably cooler judging by the touch test :)

I reckon the outside coating just makes it look pretty.