Exhaust heat shield C250D 1995

[jools182]

Hi

Just came back from a trip to Devon and noticed when I pulled up a horrible rattling coming from under the car

On inspection it looks like the heatshield has come away from its rear mountings

How are they fixed on? If its bolts it looks like they have corroded all the threads

How would I go about getting it fixed back on?

 

[hmang]

mine are fixed by a nut to a captive thread ...8mm deep socket req'd...6sided gives best grip to rusty nut.

use plenty of squirt to lube the rusty thread.

repeated back and forward small steps when undoing should help remove the nut without snapping the thread.

then flatten out the contact area of the heatshield as best you can, and use a large repair washer if ther is enough metal left on the shield.

DON'T over tighten the nut or the stud will snap...trust me, and that makes things more complicated.
use some thread lock if you think it needs some help.

 

[jools182]

I am pretty sure the threads are completely shot, so not really sure what to do

 

[television]

I am pretty sure the threads are completely shot, so not really sure what to do

Some folk pop rivet them back on, If you did this great car is needed when drilling as when the drill goes through the floor you must just penetrate the metal, other wise the drill will pick up the under felt and wind itself around the drill bit and impossible to get out. If you do this, use a coach type washer between the rivet and the heat shield

You could use a self tapping screw

 

[hmang]

I am pretty sure the threads are completely shot, so not really sure what to do

the nuts they use have a funny swaged extension to the thread.
this makes it look like the thread of the stud is knackered.

just carefully try to undo one, its got to come off any way.
use some lube and back and forth action to clean the muck from the thread as you go

 

[brandwooddixon]

Had this problem on my E class. The nuts used hardly appear like real nuts at all, but a odd cap tytpe arrangement.

Anyway easily fixed, just added some larger washers and stuck it all together with instant gasket.

I think that the main problem is that disimilar metals are used in the heatshield and the nuts. This causes corrosion where the nut "washer" meets the heatshield. Just make sure that you use something between the washer and the heatshield otherwise you'll be in the same position in a year or so.