possible warped exhaust manifold?

[petrolhead63]

the TD5 truck screaches/ under load.....more a whistle, I can play tunes by lifting/pressing the accelerator quickly. It points to a warped manifold. Drive gentle, under 2500rpm and no sudden changes and little or no whistle.

All studs appear in place, I think there may just be a little soot around rear of manifold but there is some general filth around here making it hard to be sure.

Has anybody had warped manifold with all studs still there?

Who has fixed it how.

skimmed manifold...how much?

used good manifold

one of those cheap e-bay modified ones ??

any feedback gratefully received.

rear brake pipes done in copper now ;0)

Possible

[Blanco]

I only had one stud actually sheared, but not quite detached, and enjoyed the full whistling symphony, .... my manifold was 0.6mm out of true when dismantled. The machinist made 4 passes to correct it (I think he said, ... more passes equals more money). I bought a second hand one, removed the webs myself, polished on a proper 'flat' and it was no better when fitted. so a few weeks later I refitted the re-machined original. The noise was little better when I had finished ; I went on to replace the turbo itself because I found a problem with the waste gate actuator and that seemed quite dear by itself, so bit the bullet and got the full assembly. It still whistles.... I don't know why. Bottom line is how does it drive? never mind the noise, it is a pita to dismantle,... but not really difficult, the blowing manifold (it probably is) can be cured but you can't guarantee it changes the tune.

[Shackleton]

Had mine skimmed, it was visibly warped. My usual machinist surprisingly said he couldn't do it because his mill wouldn't hold the manifold, in the end I paid a guy who made a clamp/cradle so his mill could grip it - €50 for the job. I should say it never whistled but soot was evident and the foremost stud had sheared. I think mine was warped enough that the gap was too loose to allow it whistle, I wouldn't have known only I had it off whilst doing the head gasket. Perhaps a previous owner had had a go as one of the rearmost studs was without it's nut too.

As Blanco talked about some recommend grinding away the webs between the branches on the manifold to stop it warping again, others say leave well enough alone as it's unlikely to have any more warping to do. Considering the extent mine was warped I couldn't imagine it changing shape any more so I left well enough alone and 7k miles later all is as it should be, no soot or whistles (with new stud and all nuts in place). Something I've no direct knowledge on but iirc I read that Td5 manifold warping can be due to misadjusted boost, so you might want to look into that.

[petrolhead63]

Thanks, that's interesting. The whistle I ignored for some years but it has got worse.

However I have now looked at it a bit more and I think the flexi pipe is split inside...its sooty.

also....hold a rag over the exhaust pipe whilst idling and I can make a whistle.....so it would seem to be the flexi or the manifold gasket leaking when pressured up a bit.

I will add another post about exhausts to the forum.

The truck by the way has of late started not driving so well....hoof it hard and it coughs and hesitates on its way up to high revs.