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Discussion Starter #1 (Edited)
The thermostat housing on my 2002 ZTW started leaking badly, so I replaced it last week. But still a small amount of leak happens after I drive and park overnight. I opened the hood and checked around the thermostat housing - there was a small liquid trace left on the transmission housing under where the two lower front hoses meet the housing, and when I touched under where those hoses are clamped, I felt liquid.

From a YouTube video I learned that a clamp leaves groove on a hose and deforms it over time, and when re-attaching if you don't fit the clamp in the same way it did before, you can get slow leak. I'm replacing the upper radiator hose since it looks pretty badly warped, along with the worm clamps. All of the clamps around the housing had already been changed to worm ones, so it's impossible for me to find and fit the grooves... (not like the big triangle marks from the spring clamps)

1) Is there a sealant I can use to help fill gaps at hose ends?
2) Is using two clamps a good idea?
3) Should I really be using spring clamps?

I would appreciate any knowledge and experience shared!
 

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The front stat cover can be bought with a grooved outlet or plain one depending on the year.

When you use worm drive clamps you have to go back in a second time to retighten them as they do not self-adjust tighter like the spring clamps do automatically. The hose gives some as it sits after tightened and you then have to retighten to get fully tight back.

Once you have formed grooves inside hose end from a grooved outlet you will often never get it lined back up to have grooves perfectly where they went inside hose, new hose time or use non-grooved outlets.

https://www.rockauto.com/en/moreinfo.php?pk=819169&cc=1434716&jsn=562&_nck=IKgGzllilCPCgjSv/HDXggaZWOCFnGlqUdeX5I9R4RjMGv3Vu9gkKwO2wp8rqs8HWOtcH/KVqvCk+Z7D3IMG3TUdUZ2XvCJwTlSVLLKBJPYefVA4ruj+FsFJi8YBv9XL7XtFmrziQJT1LUWQRzqUJLp1kf17WnmLnjkjg3kLIehOdKkSnUVdemFeknn6AdlBQ3cXJA+olkHKII8ZPaXLbo0U2zVDcumJwgtyReoftinBZLkNgzNHV3FslnXVoD/EtMUa/FH***Cs9ZWTd4EozvTK0RfcagCveBRAL2Ax53vqtjoO/AQ5u2dp2zfoV4WxAm9/4F5Q9lwF7JmhFkTynCtKoWAtmgoigz6x2hFgyqFr2HEZcvIYipAYUh2Vb35Fb9VckfwVqYDw+UGZKYgTAOvwm5N1HIIdWRF9eGOGlODkxMZ8yVV1ng==


https://www.rockauto.com/en/moreinfo.php?pk=10712492&cc=1434716&jsn=561&_nck=IKgGzllilCPCgjSv/HDXggaZWOCFnGlqUdeX5I9R4RjMGv3Vu9gkKwO2wp8rqs8HWOtcH/KVqvCk+Z7D3IMG3TUdUZ2XvCJwTlSVLLKBJPYefVA4ruj+FsFJi8YBv9XL7XtFmrziQJT1LUWQRzqUJLp1kf17WnmLnjkjg3kLIehOdKkSnUVdemFeknn6AdlBQ3cXJA+olkHKII8ZPaXLbo0U2zVDcumJwgtyReoftinBZLkNgzNHV3FslnXVoD/EtMUa/FH***Cs9ZWTd4EozvTK0RfcagCveBRAL2Ax53vqtjoO/AQ5u2dp2zfoV4WxAm9/4F5Q9lwF7JmhFkTynCtKoWAtmgoigz6x2hFgyqFr2HEZcvIYipAYUh2Vb35Fb9VckfwVqYDw+UGZKYgTAOvwm5N1HIIdWRF9eGOGlODkxMZ8yVV1ng==
 

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Discussion Starter #4 (Edited)
The front stat cover can be bought with a grooved outlet or plain one depending on the year.

When you use worm drive clamps you have to go back in a second time to retighten them as they do not self-adjust tighter like the spring clamps do automatically. The hose gives some as it sits after tightened and you then have to retighten to get fully tight back.

Once you have formed grooves inside hose end from a grooved outlet you will often never get it lined back up to have grooves perfectly where they went inside hose, new hose time or use non-grooved outlets.

https://www.rockauto.com/en/moreinfo.php?pk=819169&cc=1434716&jsn=562&_nck=IKgGzllilCPCgjSv/HDXggaZWOCFnGlqUdeX5I9R4RjMGv3Vu9gkKwO2wp8rqs8HWOtcH/KVqvCk+Z7D3IMG3TUdUZ2XvCJwTlSVLLKBJPYefVA4ruj+FsFJi8YBv9XL7XtFmrziQJT1LUWQRzqUJLp1kf17WnmLnjkjg3kLIehOdKkSnUVdemFeknn6AdlBQ3cXJA+olkHKII8ZPaXLbo0U2zVDcumJwgtyReoftinBZLkNgzNHV3FslnXVoD/EtMUa/FH***Cs9ZWTd4EozvTK0RfcagCveBRAL2Ax53vqtjoO/AQ5u2dp2zfoV4WxAm9/4F5Q9lwF7JmhFkTynCtKoWAtmgoigz6x2hFgyqFr2HEZcvIYipAYUh2Vb35Fb9VckfwVqYDw+UGZKYgTAOvwm5N1HIIdWRF9eGOGlODkxMZ8yVV1ng==


https://www.rockauto.com/en/moreinfo.php?pk=10712492&cc=1434716&jsn=561&_nck=IKgGzllilCPCgjSv/HDXggaZWOCFnGlqUdeX5I9R4RjMGv3Vu9gkKwO2wp8rqs8HWOtcH/KVqvCk+Z7D3IMG3TUdUZ2XvCJwTlSVLLKBJPYefVA4ruj+FsFJi8YBv9XL7XtFmrziQJT1LUWQRzqUJLp1kf17WnmLnjkjg3kLIehOdKkSnUVdemFeknn6AdlBQ3cXJA+olkHKII8ZPaXLbo0U2zVDcumJwgtyReoftinBZLkNgzNHV3FslnXVoD/EtMUa/FH***Cs9ZWTd4EozvTK0RfcagCveBRAL2Ax53vqtjoO/AQ5u2dp2zfoV4WxAm9/4F5Q9lwF7JmhFkTynCtKoWAtmgoigz6x2hFgyqFr2HEZcvIYipAYUh2Vb35Fb9VckfwVqYDw+UGZKYgTAOvwm5N1HIIdWRF9eGOGlODkxMZ8yVV1ng==
Thank you for your reply! Ah, silly me, so it might just need retightening... I'll see if retightening a few times makes the hoses sit better. If that doesn't fix, I'll go ahead and replace with the new hoses which I've ordered on Amazon. The "bypass hose" was hard to identify online but now I know the one that works - "Gates 19276 Heater Hose". Someone on Amazon was suggesting T-bolt clamps instead of worm clamps but using two of them on every hose would cost quite a bit...

I did wonder about the grooves on the housing I saw on some videos - which I didn't see any on the older part I took off (OEM?) or the Dorman one I replaced with.
 

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Yes, that is a given norm to have to retighten the clamps if they are worm drive type, I'll do it anywhere from 2 weeks to a month after the first install. The term there is likely mostly incorrect, those hoses flow out of shape at hot much more than cold so it should be referred to as hot flow instead. I should say I have switched to non-grooved outlets too, the grooved ones also crack easier.

Why Ford uses the spring type clamps, they retighten on the fly but when you expand them and they are old they do not go back on as tight as when they were new. Faster too and mainly why they use them on the assembly line.

When you assume you will have to retighten you then hit upon the issue of how to get back to the back fitting on the stat housing, I always place that clamp where I can get to it later for the second time. I have preslotted the coil bracket at the lower holes too, it means you only have to loosen the bolts rather than remove them, which can have you cursing Ford when you have to yank the coil bracket off head. I slot the bottom holes out on the down side to simply have the bracket slide off past the bolts which stay in place once barely loosened. Makes getting to that back hose easier if needed.

FYI, you can use simple bulk straight heater hose in the correct size for almost every water hose on a Focus except for the upper and lower rad hoses themselves, been doing it for years. I use bulk atx cooler hose for the smaller bypasses that go to the water bottle.
 

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Here's one you may not know about..............the front stat covers are prone to leak at around the 4-5 o'clock position to then drip down to look like the smaller bottom hose is leaking but it isn't. Ford changed the bolt pattern from an even 3 equally spaced holes to a lopsided one that is a 3 bolt pattern but basically intended for 4 bolts with one left missing, the 4-5 position is where it would have gone. The covers were modded away from the much stiffer bakelite material on the early cars to then use ABS plastic and that plastic flexes at the point where the bolt is missing to slowly drip leak. Ford even went so far as to create a weakening notch there to make sure the leak was even more prone to occur. Nice.

I've seen even brand new covers leak there. It's another flaw Ford modded to produce to bring the cars down faster, the previous design worked much better. Better bolt pattern, better material, no notch to leak. One of the things Ford does to have me claim they are tearing the cars up faster by design, they last too long to not sell more cars. It sells far more parts too. You can find later mods that do stuff like that all over the cars now, I call them nuisance issues, all are fixable but they break enough that you get annoyed enough to buy a new car when they all stack up and Ford hopes it will be another of theirs. I for one went back to the Contour stat housing which is bulletproof and never breaks to fix my 2 cars. Similar to the Contour ignition coilpack, which never breaks either even though the Focus one does on almost a yearly basis. Similar to the Contour alt which never broke as compared to Focus alt which breaks every 2 years.........ah, you've got me started again..........my belief is that Ford has turned the engineers inward to figure out ways to make the cars break small things faster without being caught at it, no one looks for car recycling as being over nuisance issues, it being more of a subliminal thing. You don't want things breaking on a year old car, but if you can make lots of things happen at 3-4 years that is a good thing. People begin to think it is normal then when you can clearly see the evolution of the parts to make them weaker and weaker to die in the future. Ford is now a master at that.
 

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Discussion Starter #8
When you assume you will have to retighten you then hit upon the issue of how to get back to the back fitting on the stat housing, I always place that clamp where I can get to it later for the second time. I have preslotted the coil bracket at the lower holes too, it means you only have to loosen the bolts rather than remove them, which can have you cursing Ford when you have to yank the coil bracket off head. I slot the bottom holes out on the down side to simply have the bracket slide off past the bolts which stay in place once barely loosened. Makes getting to that back hose easier if needed.
You're right, I found getting to the back side difficult... There is a YouTube video walking through housing replacement by 1A Auto where the guy first took off the wire harness attached to the coil pack - I did that, and luckily I got access to the screw on the clamp, although very tight. Taking off the housing just to tighten that back screw would not be fun...

FYI, you can use simple bulk straight heater hose in the correct size for almost every water hose on a Focus except for the upper and lower rad hoses themselves, been doing it for years. I use bulk atx cooler hose for the smaller bypasses that go to the water bottle.
That's pretty cool - you could replace the entire cooling system tubing for real cheap!

Here's one you may not know about..............the front stat covers are prone to leak at around the 4-5 o'clock position to then drip down to look like the smaller bottom hose is leaking but it isn't. Ford changed the bolt pattern from an even 3 equally spaced holes to a lopsided one that is a 3 bolt pattern but basically intended for 4 bolts with one left missing, the 4-5 position is where it would have gone. The covers were modded away from the much stiffer bakelite material on the early cars to then use ABS plastic and that plastic flexes at the point where the bolt is missing to slowly drip leak. Ford even went so far as to create a weakening notch there to make sure the leak was even more prone to occur. Nice.
I felt liquid where the lower smaller hose is connected so I assumed that hose was leaking (in addition to the bigger upper radiator hose), but it's good to know the problem could also be the thermostat cover, which I will definitely check. In my case I just replaced with a new thermostat housing entirely and it's Dorman, but maybe I never know...

I've seen even brand new covers leak there. It's another flaw Ford modded to produce to bring the cars down faster, the previous design worked much better. Better bolt pattern, better material, no notch to leak. One of the things Ford does to have me claim they are tearing the cars up faster by design, they last too long to not sell more cars. It sells far more parts too. You can find later mods that do stuff like that all over the cars now, I call them nuisance issues, all are fixable but they break enough that you get annoyed enough to buy a new car when they all stack up and Ford hopes it will be another of theirs. I for one went back to the Contour stat housing which is bulletproof and never breaks to fix my 2 cars. Similar to the Contour ignition coilpack, which never breaks either even though the Focus one does on almost a yearly basis. Similar to the Contour alt which never broke as compared to Focus alt which breaks every 2 years.........ah, you've got me started again..........my belief is that Ford has turned the engineers inward to figure out ways to make the cars break small things faster without being caught at it, no one looks for car recycling as being over nuisance issues, it being more of a subliminal thing. You don't want things breaking on a year old car, but if you can make lots of things happen at 3-4 years that is a good thing. People begin to think it is normal then when you can clearly see the evolution of the parts to make them weaker and weaker to die in the future. Ford is now a master at that.
I'll definitely consider swapping some parts with Contour ones... Apart from stat housing and coilpack, which parts can be substituted?

I saw a video showing how 3D printing evolution will soon change what we think of manufacturing entirely. Maybe that will help keep monopolistic powers in check. Maybe not too soon, but it'll be great to get to use materials we like and modify parts anyway we want. Plus parts will always be available however old the car gets.
 

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The thermostat housing on my 2002 ZTW started leaking badly, so I replaced it last week. But still a small amount of leak happens after I drive and park overnight. I opened the hood and checked around the thermostat housing - there was a small liquid trace left on the transmission housing under where the two lower front hoses meet the housing, and when I touched under where those hoses are clamped, I felt liquid.

From a YouTube video I learned that a clamp leaves groove on a hose and deforms it over time, and when re-attaching if you don't fit the clamp in the same way it did before, you can get slow leak. I'm replacing the upper radiator hose since it looks pretty badly warped, along with the worm clamps. All of the clamps around the housing had already been changed to worm ones, so it's impossible for me to find and fit the grooves... (not like the big triangle marks from the spring clamps)

1) Is there a sealant I can use to help fill gaps at hose ends?
2) Is using two clamps a good idea?
3) Should I really be using spring clamps?

I would appreciate any knowledge and experience shared!
Hi,
Ive dome a few Zetec thermostat housing replacements and if done correctly, with good parts, they dont leak for a long time.

Are you certain its leaking at a hose? If so you need to address if the hose ends are too worn or the clamps are worn/damaged/not tightened.

If the leak is at the housing-to head seal:
Did you use a Ford or aftermarket housing/seal? A lot of the aftermarket housings/seals are poorly made (inferior molding/polymer, poor seal material, etc)
Did you thoroughtly clean the surface of the head where the housing/seal seats? This is critical.
Did you chase out the threaded holes in the head?
Did you use new bolts or at least clean the old bolts?

Paul
 

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Discussion Starter #10
Hi,
Ive dome a few Zetec thermostat housing replacements and if done correctly, with good parts, they dont leak for a long time.

Are you certain its leaking at a hose? If so you need to address if the hose ends are too worn or the clamps are worn/damaged/not tightened.

If the leak is at the housing-to head seal:
Did you use a Ford or aftermarket housing/seal? A lot of the aftermarket housings/seals are poorly made (inferior molding/polymer, poor seal material, etc)
Did you thoroughtly clean the surface of the head where the housing/seal seats? This is critical.
Did you chase out the threaded holes in the head?
Did you use new bolts or at least clean the old bolts?

Paul
Thank you for chiming in!

I used a Dorman part (902-201), since it has pretty good reviews on Amazon and comes with a new thermostat. I did spend a good amount of time scrubbing off the old gasket material around the engine surface with break cleaner with microfiber cloth (didn't want to use abrasives). The bolts I took off were surprisingly clean, so didn't clean but they went in smoothly. Torqued to 80 inch pounds (got this from the 1A Auto video).

Yesterday I re-tightened the screws on the worm gear clamps, as amc49 suggested, and went for a test ride making sure the engine gets up to the operating temperature. Today the amount of leak I found was considerably less... so I'm hoping re-tightening one or two more times will secure the hose ends permanently.

But I'll never know for 100% sure so I'll keep checking for other possible leak spots. I'll post an update in a few days!
 

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Thank you for chiming in!

I used a Dorman part (902-201), since it has pretty good reviews on Amazon and comes with a new thermostat. I did spend a good amount of time scrubbing off the old gasket material around the engine surface with break cleaner with microfiber cloth (didn't want to use abrasives). The bolts I took off were surprisingly clean, so didn't clean but they went in smoothly. Torqued to 80 inch pounds (got this from the 1A Auto video).

Yesterday I re-tightened the screws on the worm gear clamps, as amc49 suggested, and went for a test ride making sure the engine gets up to the operating temperature. Today the amount of leak I found was considerably less... so I'm hoping re-tightening one or two more times will secure the hose ends permanently.

But I'll never know for 100% sure so I'll keep checking for other possible leak spots. I'll post an update in a few days!
Good job
[thumb]
Paul
 

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Watch the coolant level, when you have fixed it the level will quit slowly dropping. It'll take a month to be sure. BTDT more than once on two cars. Focus slow leaks are a known flaw due to the number of hoses there.

The Dorman stat cover is one that can leak, Dorman ABS plastic is more flexible than the Ford stuff. I made up a checking test fixture to pressure test the new stat housings and how I verify the problem. You can also see the amount the cover warps at the 4-5 point due to that notch, it never clamps dead flat like it should. At some point I intend to make a simple shim plate that has a screw that impacts the cover at the flex point to shove it in further to seal better, idea still in my head but should work.
 

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I should add I have found aftermarket front stat cover gaskets that are not as thick as they should be, the chain store ones do that, thinner rubber used.

Once you break seal on an original housing install the next one does not go back in place at the same spot, the bolts have slack in the holes. The original location will corrode slightly and right to the very edge of the new gasket sealing point. I clean using brass toothbrush and a razor blade drawn across the flat there to guarantee flat and then use a small spot of silicone rubbed into any lows in the flat due to corrosion that the brass toothbrush opened up, the silicone plus the new gasket then seal very well even if you have dents running across your sealing surface. I will not fill the coolant for long enough to let the silicone set up well.
 

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Discussion Starter #14
Watch the coolant level, when you have fixed it the level will quit slowly dropping. It'll take a month to be sure. BTDT more than once on two cars. Focus slow leaks are a known flaw due to the number of hoses there.

The Dorman stat cover is one that can leak, Dorman ABS plastic is more flexible than the Ford stuff. I made up a checking test fixture to pressure test the new stat housings and how I verify the problem. You can also see the amount the cover warps at the 4-5 point due to that notch, it never clamps dead flat like it should. At some point I intend to make a simple shim plate that has a screw that impacts the cover at the flex point to shove it in further to seal better, idea still in my head but should work.
I should add I have found aftermarket front stat cover gaskets that are not as thick as they should be, the chain store ones do that, thinner rubber used.

Once you break seal on an original housing install the next one does not go back in place at the same spot, the bolts have slack in the holes. The original location will corrode slightly and right to the very edge of the new gasket sealing point. I clean using brass toothbrush and a razor blade drawn across the flat there to guarantee flat and then use a small spot of silicone rubbed into any lows in the flat due to corrosion that the brass toothbrush opened up, the silicone plus the new gasket then seal very well even if you have dents running across your sealing surface. I will not fill the coolant for long enough to let the silicone set up well.
So I'm happy to report that after re-tightening those screws 3 times in the last few days the amount of leak is now down to just a few drops! (on the trans bell housing) And the lower hose stopped leaking. And no more puddles on the ground.

I'll definitely keep watching the coolant level... Good thing I just bought a refractometer so when the level goes down it's a good time to make balance adjustment.

Good to know that Dorman stat cover can cause leak. It's added to my check list, especially at the 4-5 o'clock position.

In any case, I really appreciate your advice on re-tightening the clamps which was right on the money. If dripping persists I'll just swap the old beaten upper hose. And re-tighten, re-tighten. Having come to understand the cause of the problem gives me great peace of mind :)
 

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Yeah, occasionally I have had to retighten a third time here or there but at some point you squeeze enough the leaks stop and for years.

Look for the plastic pipe that goes across top of radiator to break next, they don't live forever. I made up one out of Home Depot copper plumbing pipe, and indestructible that one is.
 

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Discussion Starter #16
Yeah, occasionally I have had to retighten a third time here or there but at some point you squeeze enough the leaks stop and for years.

Look for the plastic pipe that goes across top of radiator to break next, they don't live forever. I made up one out of Home Depot copper plumbing pipe, and indestructible that one is.
While searching for a replacement bypass hose on Amazon somehow I landed on the page for that part ("Heater Hose Outlet Tube") and learned so many people had to replace it. That's great you could substitute with a non-plastic tube, I'm sure it takes some creativity as to matching the hose diameters and creating the third inlet in the middle.
 
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