There is no bleed hole on the thermostat housing, only on the thermostat within the housing.

A housing purchased assembled with thermostat included souldn't leak ANYWHERE but possibly where it seals to the head if that joint/O-ring doesn't seal right.

 

There is no bleed hole on the thermostat housing, only on the thermostat within the housing.
/QUOTE]

Perhaps a pic will help. This is the old housing. What I'm calling the bleed hole is between the two screws atop the housing and sticking up like a little chimney.

 

OK, so where's the hose that should attach to that nipple?

Can't have a hose location without a hose, if your old thermostat didn't have one there you don't have a matching part. IIRC they all have that in a similar location on the zetecs, but don't have one handy for reference without looking up a picture.

 

Sailor, you're absolutely right, thank you so much. The first hose I disconnected, I stuck behind the front of the radiator to get it out of the way, completely forgot about it and never reconnected it. Duh. No more coolant leakage from the thermostat, she's all good to go.

 

Sheet happens, no problem.

That actually IS a bleed location, just a constant one to the reservoir. Better than the cars you had to bleed with a screw & bleed again whenever they got air in the system for any reason.

 

Funny thing is, the old thermostat housing looked OK, but the O-ring between the housing and the engine block was in shreds, and that's probably where it was leaking from.

Probably could have gotten away with just replacing that O-ring, but I didn't know what was leaking until I got it apart and had already purchased another housing. It's my understanding that when the housing itself starts leaking, it does so around the bottom bolt hole into the engine block and develops a crack there. I was reaaaally careful not to overtighten the bolts into the engine block for this reason, didn't want to create yet another leak.

 

The inner rim holding that O-ring in position is often the first failure point, when it moves the leak starts.

Wouldn't trust an older one anyways, too many are in poor condition along with the O-ring by the time either fails.

 

Actually, the most common fail there is not a crack do much as the inner wall collapses that supports the o-ring then it warps all out of place to leak. If that wall comes off completely enough it looks like there never was anything there, correct has a thin ridge of plastic all the way around INSIDE the rubber o-ring to prevent it folding inwards to come out of place. The 'inner rim' mentioned.

Other than that they can crack anywhere on them, the later plastic commonly if cleaned off with like a wirebrush in drill may have 10 cracks in it running everywhere, I've taken one like that to simply squeeze it hard to have it break up in multiple pieces.

The earlier Contour used like bakelite plastic there and why they never fail, the later Focus are made of ABS and it will NOT last for the life of the car. Why the Contour housing is a good upgrade...............got them on both my Foci and zero problems since doing so.

 

Good points, sailor and amc49. Guess I'm glad I replaced the housing if it was destined to fail eventually anyway.

 

You can thank Ford for that one, the original design at one point used to be made of metal, that of course took money away from the CEO. We just can't have that. Take your old one and look at the front stat cover dead on and the notch molded into it around 4-5 o'clock position, another thing to flaw them when the cover warps to leak right there because the notch (bolts not evenly spaced either adds to it) lets the cover relieve to leak at the stat seal. The earlier Contour part has no notch there either and the bolts are evenly spaced. Watch things like that and you begin to see the absolutely diabolic process whereby they gradually mis-design something that was reliable to then be less reliable to then sell more parts at the dealerships. There are parts like that all over the cars. I buy commonly two of each model but different years and you can easily see that over the last 20 years.

Tempo door lock links made of metal that then changed to plastic then later they mold a hole in them because they still weren't breaking fast enough. The hole could be placed right where little effect but no, they put it right where it weakens part the most. That is NOT accidental, the engineers now being used to create parts streams for more revenue rather than dependability.