In the past (retired) i have put a block of wood above between them and the body then the same on the beam jack below and squashed them to stop the rattle.

 

That’s a good shout!

 

If its in such good condition you could replace the honeycomb internals but it may take some tracking down
Here are two places that took a couple on mins to find, you may find somewhere in the UK.

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Then all you need is a angle grinder and a welder and a touch of skill.

 

The best thing to do is just pinch the casing, as suggested above, as the monoliths inside may not actually be broken, just come loose. Nothing to lose. I had this also with a BMW 840Ci, 1997, with under 10k miles.

 

Ok thanks. if i went down the route of squashing the cats then would it damage the car if i put a piece of wood behind and forced it against the body?

 

No, don't force against the body. Some people say to hit the cat can with one strike of a hammer, just enough to create an indent. Or else, you can try to use use a clamp (such as a 'speed-clamp' with a wide opening) and tighten sideways across each cat to create a slight depression in the can.

 

Never had any problem the way i used.

 

Ok, so the plan of action is to take it for an MOT and if needed then the company will fit some sports cats if it fails on the first attempt.

 

Let us know how you get on.

 

unless the rattle is really bad or the cats are disintegrated and not working, it should not fail an MOT. It's worth trying the fix first as you have nothing to lose.

1.) be aware that many aftermarket Cats do not contain the same amount of precious metal as the originals, due to cost.
2.) sometimes rattle will fix itself as the monolith will wedge itself into a new position.
3.) if you want real sports cats, these have a rolled-up, metal matrix element, creating a honeycomb structure, which has thinner walls than the ceramic blocks and also does not crack. The 850CSi has this type.

 

Thanks Arnie. I feel that I should give it another go after your response. I have a couple of clamps and will have a go with them and pinch them inwards although they do appear to be relatively strong so I am a bit dubious of the outcome.

TBC….

 

The method i said won't damage the car just take it slowly.

 

As mentioned above, If the wood beam behind the cat is wide enough, it will spread the load and should not damage the car's underside, although you'll have to be careful of the heat-shields. You could also try a variation with a ball-peen hammer on the jack, with the ball-end facing up, to create a small circular pinch point on the cat.

If you do replace the cat, the pictures below, show the difference between a true sports cat and a conventional ceramic one. The former has more surface area and less restriction to the gasses, as well as not being prone to cracking.

 

Well it passed its MOT. The cats stopped rattling for the test and must have jumped into place. The garage are pricing up some new BMW cats vs some 200 CEL cats and will fit them once the car is registered and I’m able to drive it.

In the meantime I have been busy with removing the headliner, changing the rubber windscreen seal and the windscreen tray over the weekend. Also, have a replacement chrome strip which I am in the middle of fitting but waiting on some replacement clips that I managed to break.

Thanks for all the help to date. I’m sure I’ll be back for more very soon!

Some photos of the work over the weekend for those who are interested.

Tray before:

And after:

Windscreen seal:

And lastly the headliner out and ready to send to the trimmer. Just need to figure out how to take the sunroof piece off before he collects:

 

Looks like a lovely car. The E38 was the best car I ever had and it looks like you've found a great example.

Here's a link to the headliner replacement on an e31, which uses the same material:

Headliner failiure | BMW Forums : BimmerForums

 

Try these people for free samples of possible headliner materials:
Boyriven - Independent Fabric Supplier

They recommend "Dinamica" and "Siena" for good results, as these are stretchable, ensuring the contours and recesses can be properly covered but they carry many brands/types.

 

Thanks Arnie. I’m of the opinion that its worth doing once and properly and given that the car is in such great condition and with such low mileage, it deserves to look its best.

I’m still not 100% sure how to attack the sunroof but will have a look in a while when I‘ve finished working for the day.

 

Car underneath looks impressive, may be Japanese import is a good idea. Thinking Jaguar xjr 308 ouch I hear you!

 

They are definitely free of rust in the usual places. This is my second import and I have another arriving in a couple of weeks. The Jag would be a great car!

 

Nice to get the pass.

 

I was quite relieved.

Had some more good news thus morning; the DVLA called this morning to ask for one detail on the registration form. They confirmed all was fine and that the new V5 will be with me in the coming days. Much faster than I had expected given the timescales from when I have done this previously!

 

Result.
You will have to put some pictures up with it's new id front and rear.

 

Made some more progress this evening. Managed to remove the sunroof and the interior trim attached ready for the trimmer to sort in the coming fortnight.

Also a box of goodies for the old girl arrived too.

 

The trimmer finished and dropped off the headlining and associated parts. It took me a few hours to get them back in the car on Friday but the results are stark and so much better than the light grey sagging material. The only issue is that the headlining around the sunroof has a slight lip where the alcantara is rubbing against the alcantara sunroof cover and as such it is giving too much friction which stops the sunroof from opening fully without any manual intervention. The trimmer is coming over this week to take a look and see if he can make any suggestions but I’m over the moon otherwise.

Took the chance to change the cabin and air filters and list an oil change sometime soon to come.

 

Looking good very good.

 

Time for an update.

The E38 went in to the local specialist on on Friday and left the car with them for a few days to sort out at their leisure. It had a suspension arm and the profusion 200 CEL cats fitted. They did an excellent job of welding them in place and the rattly agricultural noise has now gone and the exhaust note is slightly fruitier than before but to a non car person it would seem completely normal. Put a few more miles on the clock today and absolutely love the comfort this car offers. It is so much better than any other car we own.

 

Went to a local breakfast meet this morning and ended up seeing some of the local cars from the classic car club south west. The 7 seemed very happy on the way there and back although one of the door seals was probably not fitted correctly given that there was a slight whistle as higher speeds.