Rattling thermostat? (1 Viewer)

[mercfan]

I've been trying to track down a new noise under the hood for over a week now. I thought it was the Waterpump at first, but today after spending more time listening to the engine and touching various parts while it's running I discovered that the noise emanates from the thermostat housing - it sounds like a rattling muffler sound.

Here is a short video I took few days ago:
https://photos.app.goo.gl/SxGaRpu8Qz2pkKfC7

The noise/rattle seems to be coming from the thermostat housing and can be felt distinctly in one of those three areas as shown in the pic below:
https://photos.app.goo.gl/Y7F8yAVo97H9Uhy1A

I hope you'll be able to see the pic and video I attached.

Another observation: when I felt the rubber hoses that come out of the bottom of the radiator up to the thermostat housing, both of these rubber hoses were 'imploded' - like there was suction in them - is that normal on a cold engine with thermostat normally closed?

 

[MoJ]

Have you recently replaced or otherwise accessed the thermostat?

 

[mudgudgeon]

No, the hose shouldn't suck in.

Removing the thermostat is relatively easy.
I'd remove it and inspect it, for the cost, replace it with OEM.
good time to put a flush through the coolant system, and fresh coolant too.

 

[mercfan]

Have you recently replaced or otherwise accessed the thermostat?

No, I have not touched it.... I have the coolant and new thermostat ready - I plan on replacing and doing a flush weather permitting.