The Duchess has had a mild tick for a long time now, and this time round she got an advisory for a slight leak of exhaust from the manifold.
Today I overtook a van with full beans and suddenly I'm driving a steam train!!
Call me a wimp but I really don't have a clue where to go next. She'll probably got to the local garage (who have been very good) but just in case, are there any simple things I should try first? I'm guessing that it's likely I'll need to pony up for a new (passenger) manifold - are there any recommended ones?

Thanks!
Miles

Or do I just buy industrial quantities of Plus Gas and man up?

By steam train I hope you mean noise, not a trail of steam behind you.

Yep, just noise. It eases off on over-run, and it's pretty grim on acceleration. We're still running on all 8 smooth as ever.

is it the manifold it self and not just the gasket given out
have a look on lrcat and get part number and do bit of online pricing so you know how much your looking at

When I've had that sudden change, its been a chunk of gasket thats let go and left a gap. You can usually seem some marks where its leaking. Could be either end of the manifold, see if you can see any sign of where it may be leaking would be where to start. Much easier if you can get it on a lift. Wouldn't be a bad idea to give bolts a good soaking while your under there too.

If not gasket it'll be the short Flexi pipe split on the manifold

Good call :) I'll have another proper look - I couldn't see anything with a quick peek by the side of the road. Soaking bolts can't be a bad idea either...
The gaskets are interesting. 2 Quid from Britpart or 40 from Land Rover!

I'm building a 3.9 V8 and I found britpart quality is not bad now as they got rid of the dodgy stuff people bought and then moaned about ---- soak manifold bolts in plusgas and gently ease loose/tighten loosen ---- slowly and you should be able to get them out ---

Unlikely to be the head to manifold joint if it suddenly got worse from booting it. Might be from the manifold to downpipe joint (and it's blown a bit of gasket out) or it could be the manifold itself. Manifold to downpipe isn't too bad. 3 nuts on M10 studs. Nuts might come off (with the aid of Plus Gas) or the studs will unscrew, it doesn't really matter. If the manifold needs to come off, all bar one of the bolts are easy enough to get at, one, the furthest to the front on a passenger side (rather than the one furthest to the back on the drivers side), can be a pain.

Get a bit of plastic tube and, with the engine idling, shove one end in your ear and wave the other end around the manifold. You should be able to identify where it is blowing from.

Or a blow from the headgasket.

Simple way to detect a leak - tape a short length of tissue paper to the end of a stick with about an inch protruding over the end and then go round the manifold and joints. The tissue will flail around even at the slightest leak. May need to stall the fan or at least shield the ‘test probe’ from it during the test. The beauty of this method is you don’t burn your hands and you can get right around the manifold to downpipe joints with ease.

If manifold bolts need to come out plus gas and patience are the order of the day. Soak bolts thoroughly hours before you attempt the job and then start with a (very) small tightening to barely move the bolt and then it’s very slight loosening before very slight tightening and continuous rinse and repeat with the loosening being just a bit more than the tightening until the bolt frees and can be taken out. It takes time but not as much time as trying to remove a sheared bolt!

I've never had a problem with manifold to head bolts, they just come out. The only difficulty is access to the front one on the passenger side as it is under the AC compressor. Spraying Plus Gas onto the head of a bolt isn't going to do a lot either. It's getting the heatshields off first that normally gives grief.

Here's a Vid!

Sort of, anyway. You can save it if you right click the link and trust me!

Sounds like this to me.

https://youtu.be/i0vy5wgQDCM

Or this https://www.youtube.com/watch?v=dKEqPY5rX7A, which was the head gasket blowing out the side of the block/head joint just below the exhaust manifold.

Damnit. You're both right! Ah well. I guess it's still fixable as long as I didn't torch the head driving it for 50 miles home...
Thanks - you saved me a ton of arseing around :)

It won't do a lot of damage if you treat it gently. The one that I did had been doing it for a few days before being driven 45 miles to me at a steady 80mph. Off with the head, a light skim and back on. Did the other side while in there as it didn't seem worth just doing the one. Took me two days but half of that was taking the heads in and waiting while they were done.

I drove mine for several hundred miles with a blowing head gasket as I assumed that it was the exhaust blowing somewhere. Performance was unaffected it just got too embarassingly noisy to continue driving. I have no idea if it did any permanent damage driving it with the head gasket blowing but it's currently in the hands of V8 Developments waiting for them to get round to refurbishing the engine.

drove my l320 for months with exhaust manifold blow it didn't cause no problems to the head
but it did cause a load of faults with the lamba sensors causing it to over fuel so kept ailing emissions test