Has anyone noticed a rattling sound when they open up the box for a new complete thermostat housing and thermostat kit for the 4.2 L engine? I bought the complete kit from Welsh for my 2005 XK8 and before I got into the job I wanted to make sure I didn't have a defective part. Thanks much for your help.

 

I did my 03 this past fall, same as yours, I do not recall a rattling sound. Is it loud or soft? I am fairly certain there should be nothing moving around within the housing where the t-stat is located. Maybe someone can chime in.
Going to spend your money but since you have that apart may as well replace the Water Pump. That repair/wise preventative maint on this car is waaaaaay easy. I bought the orig type like what came off of it....

There are many that come with just a paper gasket. The orig comes with metal one and a oring. Here is my thread on my WP change with a few pics. It is really a easy job.
https://www.jaguarforums.com/forum/x...s-pics-131684/

 

Thanks much brgjag! Very helpful. I will have to check around some more about that rattling sound. Regarding the water pump – – did the pump you replaced have the plastic impeller? I guess those are good for about 10 years.

Any other thoughts on that rattling sound much appreciated.

 

A guess: You need to install the large rubber o'ring on the outside of the TST. Mine was shipped with the TST packed inside the housing, it still needed to be correctly assembled.

 

yea my new wp had the plastic impeller. When I first ordered one it was metal and did not have the metal gasket and no set up for the O-ring on the pump. I was not comfy with that set up so got the same thing that was on it.

 

I think I've determined the slight rattling sound is a check valve ball moving around in the housing. Great idea to replace water pump -- going to take your advice!