Manifold heat shields

[TJS]

Has anyone replaced the combined exhaust manifold gaskets and heat shields on a DIY basis ?

They are not leaking however, the rear heat shield element is holed. The original metal weave laminate style has been replaced with what looks like thick grey cardboard. See below

Pondering the job this afternoon it seems the plastic header tank and ignition rail comes off and plugs out, under tray off and loosen the manifold / exhaust clamp before attempting to undo the 12 brass manifold nuts. Space is extremely tight and a snapped stud would be a disaster, probably resulting in removal of the cylinder head to rectify. No way could you drill it out and re-tap the thread with the head in situ.

Alternatively.

1. The car is due an Inspection 1 service and a 5 year / 7k mile cam belt so do I ask the BMW dealer to fit them at the same time ? Although if they break a stud and the head comes off I assume I will pay for it.

or

2. Just live with a holed heat shield and the associated OCD.

[felix]

Given your garage how could possibly be even thinking there is more than one answer?!

[a1z1]

Hi Bluebaur has a solution that looks good and doesn't require removal of the manifold.

I changed the manifold gaskets on a z1 last year, Shall we say it was character building.

There is a tool that allows the drilling and re-tapping of the cylinder in situ .. but you do need a 90 degree head drill.

The pictured broken stud is at the rear of the engine near the bulkhead.



The nuts and studs are available as a set.

Good luck!!

[urzzz]

I don't know anything about nuts or studs, but I wonder if your coolant is a bit low? I understood that the arrows marked the 'minimum'. No doubt would be picked up at Inspection 1 anyway, but maybe one to keep an eye on. Toby

[sfh3l]

My coolant always goes down when cold and up to the line when warm

The studs do have a tendency to break, as well as unwinding themselves occasionally. I have not long ago done all of this on my 318is, where the manifold was cracked and needed welding. I got it off and removed all the studs to replace as a precaution. All came out like good boys and girls, so I was lucky.

Personally, I would suppress the OCD and live with it. It could be a bitch of a job (simple enough if all goes well) and my thoughts would be that sooner or later you'll need to do something that necessitates a head-off or engine-out job, at which point it comes into play as another little job to add to the list of things you'd do if you had to.

M20's tend to blow head gaskets and crack heads. One of us will, sooner or later experience this and that is a perfect opportunity to attend to nasties like this one. Till the, for me at least it is another of those dogs that continue to sleep soundly

[Jet]

They are not leaking however, the rear heat shield element is holed. The original metal weave laminate style has been replaced with what looks like thick grey cardboard. Just live with a holed heat shield and the associated OCD.

OCD is usually triggered by the 'visible', so as the gasket isn't the issue, and its the heatshield that bugs you out, cut away the shield leaving the gaskets in situ. Cut a new gasket leaving the shield, combine the 2 with an invisible join, no more OCD.

After 28 years and 30k miles, I wouldn't attempt to remove those nuts unless necessary.

[sfh3l]

[/quote]

OCD is usually triggered by the 'visible', so as the gasket isn't the issue, and its the heatshield that bugs you out, cut away the shield leaving the gaskets in situ. Cut a new gasket leaving the shield, combine the 2 with an invisible join, no more OCD.

After 28 years and 30k miles, I wouldn't attempt to remove those nuts unless necessary.
[/quote]

Couldn't put it better myself. Get therapy for the OCD TJS and don't worry about your nuts