I'm not sure if you're talking about the "nipple" section that the upper hose goes onto, or the squarish housing that bolts to the cylinder head. If it's the latter, be careful as the sealing groove commonly fails on these. It's hard to explain but basically oil seepage from the valve cover drips down and makes the o-ring swell, which breaks the groove. It happened to mine even though there was only a light film of oil on the side of the head before replacing the valve cover gasket. Even replacing the o-ring will not cure the leak. At that point you will need to either replace the housing or use silicone RTV to seal the housing to the head, since it's more forgiving of imperfections (also makes disassembly a pain).
Good luck!
I know exactly what you are talking about because that groove was broken on the one I pulled off my car so it was probably going to be leaking soon anyway.
On another note, here's what I found out today:
The housing is relatively the same on all years of Zetec contiques.
The housing is different on Zetec escorts.
The bolt pattern to the block on contiques is different from that of the focus/cougar housing.
The housing on the focus and cougar are identical, except the cougar has two sensors that are held into the housing by metal clips. The focus has spots for these two sensors but they are not drilled through and the lower has no spot for a clip.
The end result? I have a cougar, which is noted in my sig. I grabbed one off a focus because it looked exactly the same. Could I use it? Yes. Will I? No. The reasons being that even after drilling the spots for the sensors, there still is no groove to put the clip through that will hold in the lower sensor. I could get out the dremel and make the groove but I'd rather put in the correct part. I'll keep this one as something to play with since I already drilled out spots for the sensors.
Time to call the dealer bright an early. If they don't have any in stock, I'm ordering from teamford since they are only $16 through them.
I love not being able to drive anywhere