Exhaust Manifold bellows cracked

[DaveKelly]

I need some advice - the bellows that sit between the front 2 pipes and the 4 pipe junction has cracked 'again' on my right hand exhaust manifold. I had fitted an after market bellows unit three years ago but it hasn't lasted. So the question is 'do we need that bellows unit?' Was it an over design by Land Rover? Can I weld in a straight piece of pipe and be done with it?
Also - after reading some threads on ceramic coating the manifolds - Is it a good substitute to the heat shields? :confused:

Tips for those who come down this road and have to remove these manifolds - pull the front wheel (right in my case). Remove the plastic wheel arch surround. Makes removal of all those heat shield bolts and also the rear manifold bolts a lot lot easier. Next mark well the steering spline at the steering box and pull the shaft back. NOTE the warning sign on the shaft - so do it right. You will still swear at the shields as you try to remove them (wear leather gloves - learnt from experience and lots of blood). But it is worth the extra 10 minutes work. I also make sure that I have a good chock in between the axle and the bump stops - just in case the suspension decides to drop down. I'll post up some photo's later.

Any advice will be gratefully received.

[DaveKelly]

If you are wondering how I found this leak......
On start up with bonnet open I could hear this huffing sound. After the engine came up to temp it vanished. Been here before so I know it was a small crack somewhere and when expansion occurs blocks it up (well that's my theory).
When I removed the manifold I checked the flanges for blow past - zip. But that little brass stud that is the outer heat shield attachment point (back one in my case) had black soot on it. AND the inside of the heat shield also showed signs of soot (wire woven pattern). Sort of conclusive.
Any case, here are some photo's.

[Hoges]

Hi Dave
the design of the exhaust headers probably requires the flex joint to enable the "system" to absorb expansion and vibration etc. and thereby prevent over stressing the studs connecting the manifold to the head or cracking of the manifold elsewhere. The flex joint on mine looks like this Range Rover P38 Exhaust Manifold Left Hand Side 4 0 4 6 Tublar Stainless Steel | eBay (http://www.ebay.com.au/itm/like/151071297847?limghlpsr=true&hlpv=2&ops=true&viphx=1&hlpht=true&lpid=107)
I'd replace the flex joint rather than go "solid"...

[glenhendry]

This is a great post. Informative.

Mine is the same as Hoges's, and I have had a crack in it too. Its hard to seal up, and I ended up replacing the exhaust manifold. The leak causes the O2 sensor to get confused.

Note on coating, our headers are stainless steel fyi. Also, I believe that those shields, after wrestling with them many times are very effective. I bought exhaust wrap, but putting it on those headers looked too difficult.

[benji]

I was going to post last night that mine had the convoluted expansion piece too.

Admittantly this design header doesn't loosen off the exhaust bolts like the cast headers did - maybe that's the reason for the expansion bit.

I imagine on the header of a petrol engine would be the toughest place for that type of expansion joint though. I'd you can't get any better quality ones you may be up for new exhaust manifolds. Linrover had some cheap ones a while ago - even if they're cracked in other places, they're very easy to weld up.

[TheTree]

Hi

Sounds like something worth checking for sure

Steve

[DaveKelly]

Just to clarify - the bellows shown in my photo's are aftermarket. The original bellows were true Land Rover as in the ebay photo. I tried welding the crack in the bellow unit as a temp repair - a REAL long shot I have to admit. It's paper thin. So I had a shop weld this set in (cost a heap) but it hasn't gone the distance - probably 15k which is pretty horrible. Well I dropped into a place tonight and picked up a replacement bellow - cost 33 NZD. Now that ain't bad. My task is to now cut the other one out (CAREFULLY), make up a jig to hold the pipes in the correct position/alignment and weld the thing in. This time I think I will do the weld. I will keep you posted with photo's.

Anyone out there tried the ceramic solution on these manifolds?

Cheers

[PeterAllen]

Yes I went with new ceramics and did away with the heat shields. I reckon they are really good. Pipes cool down quite fast and gives more room for other access to bits in the engine bay .Got mine from a mob in Sydney

[DaveKelly]

Hi Peter - who in Sydney? Did they supply a new manifold ceramic coated or use your old one?

I have had a closer look at mine and I think I am going to have troubles removing the after market bellows and then being able to tig around the back between the pipes. I don't know that they will have left me enough meat to use. I may have to fabricate some joiners. YUK. I am keen to give it a go but I need the 4 wheels back on the road and bringing a new set across the Tasman may be a faster option right now. I can then play with the old manifold at my leisure.

[PeterAllen]

Hi Dave, I got mine when the car was rear ended. Did the whole exhaust from the block back. Headers were from Liverpool Exhausts. (Hurricane Headers). They are made to order.
I have had them on for 18months and they still look as they were put on.
Only issue I had was the location of the stability bar welded between the front and back pair of pipes. Where they welded the rod restricts easy removal of the two middle spark plugs. I advised them to lower the rod if they did more. I will have to cut my connecting bar off in situ when I renew the plugs. Not a big deal but would have been nice to not have it in the way of plug access which is easy for them to change to avoid the problem. I will check again where the rod should be welded and let you know if you decide to go that way and at least you can tell them to avoid future problems.

[PeterAllen]

Hi Dave,
Checked mine and they welded the stabilising bar at the top of the plates of the two sets of pipes. This bar needs to be welded at the bottom of plate ( its about 30mm lower which would then be out of the way of the sparkplugs .
I am pretty sure the bar is only there to hold it all in position for transport etc as when bolted to the block has no purpose.
Good luck with it.

[DaveKelly]

An update for you all - the after market bellows unit has split. I decided I would dispense with all the stainless braid (inner and outer) on the replacement. Weld a solid piece of pipe to the front end pipes and let the tail float at the back. Then I would weld the bellows over the lot. My reasoning that the bellows has not survived the heat and maybe a solid piece of pipe might afford it some protection.
All was going well until I went to close the last piece of weld - and burnt a hole. Problem is the hole is where I can't get access. Right in between the most difficult set of pipes you could imagine. :mad:
So now it's back to square one. And a phone call to Sydney on Monday.
The photo's show the inner braid absolutely destroyed, the cracks in the bellows and the jig I made up ensure my alignments were correct in the welding process.