A common source of issues arises from the factory thermostat housing and neck, which has a plastic construction.
The problem?
Cooking components are subject to extreme temperature changes on a daily basis. This causes stress cracks on crucial cooling components.
The solution?
An all metal housing to eliminate the plastic unit. This is the same principle of plastic vs metal water pump impellers.

At $65.95 this is a small price to pay. Make your cooling system overhaul count. As we know, cooling system failures will put you on the side of the road, or worse.

Metal Thermostat Housing - With Cover

 

Nice one, I'm sure the S type owners will be happy to see this!

 

Don't want to sound like Debbie Downer but isn't the standard housing all metal? I'm pretty sure mine is.

 

Hi Norri - The 2000 - 2002.5 MY S Type w/ V8 engine thermostat housings are all plastic (cheap plastic at that) - I switched to the metal conversion thermostat housing/cap when I swapped out my water pump which failed miserably (for metal as well) - I was shocked how many stress cracks were identified upon removal throughout the housing, especially the housing cap - I had a crack straight across.

Needless to say - I feel more confident w/ the aluminum thermostat housing/cap - easy to install and adds confidence on those hot days... I highly recommend...

Now, someone needs to make a metal version of the plastic cross over pipe - as this part proves to be an issue as well with age - I also replaced that part as well with new... plastic part...