Installing a temp sensor

[DazzaG40]

So I've just bought an 02 1.8t Estate and I'm giving it a good going over. Today I changed the pollen filter, air filter, oil filter, oil, fuel filter and I was in the process of slapping in a green temp sensor when I ran into an issue.

First off the little rubber T piece above the sensor tore along the seam, I've tried a repair with black silicon but does anyone have the part name/number to order a replacement? Also it appears the previous owner mixed coolant as the little t piece was almost completely filled with dark orange/black goo, I'll try a number of flushes and keep an eye on it, I'm hoping it's not a headgasket problem.

Secondly the little clip that holds in the temp sensor bounced into oblivion so I've ordered a few new ones from ebay. My question is, does the sensor just sit in the housing or does it need to be forced into place before the clip is installed? I've heard stories of the housing crumbling so I don't want to force it if it's not necessary.

Thanks for the help.