Thermostat sleeve not sitting flush

[orangeTANG]

I'm changing my thermostat out on my 2000 Mercruiser 3.0L. I ordered the 160* thermostat, the small lower gasket, the upper gasket and the plastic sleeve. I put the lower gasket in, followed by the thermostat, then the sleeve lined up with the notch. However, no matter how hard I push I can't seem to get the sleeve to sit flush with the top of the thermostat housing. I can obviously put the other gasket on top, followed by the cover and bolt it to the 30ft/lbs of torque per the manual but this just doesn't seem right? I double checked all the part numbers and they seem right per explosion diagrams.

What am I doing wrong?

 

[Fun Times]

Was the inside of the housing built up with heavy corrosion? They sometimes need a scraping to help clean up the insides so everything will seat correctly.


Do you still have the old sleeve to compare the new one to?

If you decide to watch this youtube video of how change a Mercruiser thermostat, be sure no kids are around you as the langue is not the cleanest.

http://www.youtube.com/watch?v=Zf8vBTyN_hw