Climate Control

Rear A/C Rattle

Rear A/C Rattle

All three 928s I've owned so far have had an annoying rattle/noise from my rear AC under certain road conditions. Finally, today I found out where it comes from. And it was surprisingly easy to fix it. Took me about 30 minutes....

No, this rattle does NOT come from the vents - it comes from underneath! There is a mesh over the evaporator, and it vibrates against the evaporator. I could easily simulate it by banging on the rear AC console...

I took the rear AC cover off (see *** below), and found out that the mesh can easily pulled out after removing a (temperature) probe that is stuck through it. I cut thin felt strips and stuck them onto the underside of the mesh in order to keep it away from the evaporator.

Put things together again, banged against the rear AC console, no rattle anymore!

'91 928 S4 V8 Auto

*** Warning: If you have not done this before, be careful when you remove the black cover at the rear of the AC console. It has two screws towards the trunk, two clips on the sides, and two weird "Z" shaped metal latches towards the front. If you pull too hard, these latches break off. Make sure you have some really good Epoxy glue handy - just in case.

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