2005 XK8 4.2 aluminum thermostat housing replacement.

Old plastic housing was deforming around the head flanges and was seeping coolant.

Housing made by Mitzone. Bought off ebay for $70.00.

The replacement was super easy. It took about two hours to complete, including replacing the water pump while I was in there. The only problem I had was the car would not start after I was done. It turns out the temp sensor was bad or not compatible with the 4.2. Regardless, I reused the old sensor and it works just fine.


Appears to be an exact match

Comes with thermostat.


Comes with temperature sensor. WHICH DOES NOT WORK!!!!!


Need to remove front cover off of intake manifold to access T30 bolts. Very easy.


Old housing slides right off. No sweat.

While I was in there, I replaced the water pump. Super simple. It took ten minutes.

Install rear housing first. Tighten all four T30 bolts.

Slide forward housing onto rear housing.

Do not use temp sensor that comes with the housing! The car will not start with that sensor. I ended up reusing the old sensor. It was very strange the car started with it disconnected, but would not start with it connected.


Bolt it all back together and reattach/replace hoses. Good to go.

 

I have mine ready to install. But I replaced it a year ago with a plastic one, and I'm too lazy to replace it again (but I will). Yes, there's something wrong with thermostats; I also put the old one in the new plastic housing.

Thanks for all the advice; it makes things much easier.

 

Well done....

 

Completed my install as noted in earlier thread. the top holes spacing on the front piece on mount to block required a cleanup that could have caused a cross thread on bolts (6mm X25mmL) using a 13/64 bit along with debur. I also removed the provided temp sensor and thermostat and utilized the existing ones in the old plastic housing. I have contacted Mitzone regarding the hole spacing and Stat + Temp Sensor..

 

Why did you replace the thermostat? Was it also bad?

 

TRUST was major consideration. The included stat did not appear to be of same quality as my operational 1.
The stats are difficult to change is reason the new ones come in the plastic housings... "If its is not broke , don't fit it."