Defender TD5 - screeching noise

I have a Defender 90 TD5 with a screeching noise from one of the various parts of the RHS of the engine compartment. The noise appears at higher revolutions only and appears to emanate from the aircon compressor/turbo area.
I've already changed the turbo,the aircon compressor, the pulley to the far right and also the main drive belt in case it was slipping............none of this has helped.
It has been suggested that it could be exhaust gases passing over a crack in the EGR pipe but I am loathe to remove anything that might be heat welded together.
Anyone had a similar problem?

When you say RHS, do you mean the turbo side or the inlet manifold side?

It sounds like the typical bent exhaust manifold or broken stud on the manifold. This will screech, especially when you put the vehicle under load.

Look for sooty deposits above and below the exhaust maifold where it meets the head. It's difficult to see the back due to the turbo heat shield being in the way.

Described to me as sounding like a dentists drill. I did all the belts/idlers/tensioner and it was the exhaust manifold gasket. With the turbo heatshield off and spray some wd40 around, you could see it blowing bubbles.
One broken stud. I was quite lucky and only broke one other getting the manifold off.

You're absolutely right, one stud has broken off the exhaust manifold and the stainless steel buffer between the aluminium engine block and the manifold is acting like a reed in a wind instrument. When the engine is under load the noise is pretty horrendous.
I suppose the proper fix is to have the stud drilled out and replaced but I'd be happy not to have to go down that very expensive route and try something else instead.............any ideas?

Just to add a little more detail.......both studs from the manifold outlet nearest the radiator have broken off, so I've removed everything that's in the way apart from the EGR and have forced Gun Gum into every nook and cranny...............here's hoping I don't have to go for the (almost) engine rebuild option.

anglosearcher said:

Just to add a little more detail.......both studs from the manifold outlet nearest the radiator have broken off, so I've removed everything that's in the way apart from the EGR and have forced Gun Gum into every nook and cranny...............here's hoping I don't have to go for the (almost) engine rebuild option.

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Apparently the shearing off the studs on the manifold is a common problem and is associated with black soot around the studs and an awful screeching Noise.

As long as you cab get the old studs out it shouldn't be too much off a "rebuild".

Good Luck

Chan

Doing the job correctly is the only way forward with this as you are loosing economy if the exhaust manifold is not sealing correctly, you should also have the exhaust manifold skimmed flat before re fitting to your vehicle with a new set of studs and nuts.

Thanks for the advice about skimming the exhaust manifold, I guess I now have to go for an almost complete engine rebuild in order for the studs to be replaced.............is there any way I can wriggle around this hugely expensive repair? Can the studs be dealt with in situ or are we definitely talking big bucks?

No need to rebuild engine!

Removing broken exhaust manifold studs is completely within DIY territory (& yes it can be dealt with in situ). Even easier if no A/C fitted.

Just don't drill into the water jacket...

OK, thanks for the encouragement and also the warning.........I'll definitely be taking the plunge because the gun-gum has just about ceased to function and the awful screeching has returned when the engine is pushed. Anybody have a preference or recommendation for stud extractors?

My 2 grains of sand:

Getting studs out:
- Stay away from spiral extractors e.g. 'EZ out' as these tend to break
- Square profile straight flute extractors are a lot stronger (see pic below)
- Ensure hole is drilled as centred as humanly possible (Dremel tool is best)
- Use lots of WD40 or equivalent (Wurth Rost-Off is far superior), possibly leaving overnight

Manifold
- Cut webbing & enlarge stud holes (except those for centre cylinder)
- Then if warped reface it

Installation
- Preferably replace all studs
- Use Class 8.8 or stronger studs (alloy steel, quenched and tempered)
- Smear with copper based anti-seize compound
- If using longer studs DO NOT screw all the way in (notice how they come installed from factory)
- Use new (metallic) gasket
- Torque to specified value 25 Nm / 18 lb.ft or slightly above but DO NOT over torque


Manifold after hole enlargement, webbing removal, refacing & high temp paint treat:


Straight extractors (need to be hammered in):

Ive got the same sort of problem but it only does it in a morning when the engine is cold, and it stops once the engine is hot. it sounds a bit like a belt slipping so not sure if it needs a new tensinore

discopaul said:

Ive got the same sort of problem but it only does it in a morning when the engine is cold, and it stops once the engine is hot. it sounds a bit like a belt slipping so not sure if it needs a new tensinore

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put some talc on the belt before starting it, if it dont squeel its the belt

discopaul said:

Ive got the same sort of problem but it only does it in a morning when the engine is cold, and it stops once the engine is hot. it sounds a bit like a belt slipping so not sure if it needs a new tensinore

Click to expand...

They tend to be noisy first thing when cold, and as the metals expand when warm/hot they seal up the gap a little.

never heard of using talc, but i will give it a shot