W126 '89 300SE thrmo cover- crush ring?

[unkl300d]

Hello, I did search the archives and got some round about info but specific to this car, 89 300SE, do I need the copper crush washer for the updated aluminum thermostat cover?

background: the original plastic thermostat cover broke so I am updating with an aluminum one.

Parts vendor states that the copper crush washer might be needed.

I ordered that part as well.

I just want an idea before hand as to whether I should install it.

The water pump was replaced about 3 yrs ago and few miles driven on it.
The thermostat was replaced then so I don't plan on removing the thermostat.

I plan on simply removing the plastic cover and replacing with the aluminum new one.

I just reckon that maybe the plastic one might not visibly show the need for the crush washer whereas the aluminum one might need it.

Knowing beforehand will save me the trouble of experimenting.

Thanks !!!

[unkl300d]

OK for the archives and the curious, before your plastic T-stat cover breaks, upgrade it to the aluminum one.
The upgraded one has an opening on-top for a plug and also for an air bleeder nut.

The crush washer it turn out, was for the plug bolt.