Question Change the C4 1.6HDi Turbo / Exhaust Heat Shield
The front securing lugs on the heat shield are a known weak point on this engine and can fail through 'fatigue'.
Citroën have uprated the securing points for later models.
The lugs failing don't cause any real issues as the shield can't go anywhere but it can let hot air rise to the turbo and cause an annoying rattle (and diesels can be noisy enough.!)
A replacement only cost me £17.88 with Premier Member discount and 25 minutes to replace (including taking the accompanying images.
Step one is to remove the Engine Cover and Turbo Resonance Suppressor to gain access to the engine side securing bolts. For this you only need a 10mm combination spanner (open jaw and ring) as there is no room for a socket.
First simply lift the engine cover up and pull out (you will) need to lift the rear scuttle panel under the wiper arms at the front a bit so it slides out.)
Next you need to remove the bolt marked '2' in the picture and slacken bolt marked '1' - the resonator pipe will then come out by lifting at the left hand side to free the push fit locating lug then twisting slightly up and toward you so it clears bolt '1' then pull back toward the bulkhead.
Once clear simply move over to the left side of the engine bay so you can see the part of the shield that you need to to change
Now you need to remove the 5 bolts indicated to free the broken part of the heat shield.
Start with the 2 engine side ones and when out lay to one side.
Then remove the 3 heat shield joining ones just making sure the shield doesn't drop.
Next you have to manoeuvre the old broken shield out which will require a bit of tugging backward on the outer part.
Once out you simply re-fit in the reverse order.
Fit the shield ensuring the bolts are tight starting with the 2 engine side ones, then the 3 at the joint.
Refit the Turbo Resonance Suppressor making sure it's seated correctly and the bolts are tight.
Finally fit the engine cover
Total time 25 minutes.
UPDATE: There has been a design change at some point during engine production.
On the new design which you can identify because the left hand screw on the turbo resonator is now a Torx.
On these, this screw can't be removed as it's not possible to get a tool in.
The sequence is to remove the right hand screw, bracket and jubilee clip that holds the pipe on.
You can now swing the resonator all the way around to clear the 'new' torx screw.