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Discussion Starter #1
Here`s one for you. My Zetec is running between 190 and 200* (checked with an infrared thermometer) Engine is running great. I popped the hood today when I got home from work. I jumped back because the upper hose was huge !
Big enough to take all of the coolant out of the reservoir. When I cracked the cap on the tank to relieve the pressure, it refilled all the way to the full line. Is the cap on the expansion tank a relief style, and if so what kind of pressure should the system operate at. 14 - 17 psi ? .The hose is the original with 152,xxx miles on it. So I ordered new a new hose from CFM today. The new engine has a new water pump, and thermostat. What else could it be ?
 

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C2H5OH
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Are you running a thermostat?
If not, too much flow out of the block can overwhelm the radiator and create back pressure, expanding the upper hose.

On that same token, a blockage in the radiator can cause this.


Yes the res. cap is a pressure relief valve. Factory, IIRC, is 14psi while aftermarkets are 16psi.


Possibly there is a good amount of air in the system.
Cap off, let it idle until the therm. opens, turn the car off and let it cool. Put the cap back on.
 

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Discussion Starter #3
Are you running a thermostat?
If not, too much flow out of the block can overwhelm the radiator and create back pressure, expanding the upper hose.

On that same token, a blockage in the radiator can cause this.


Yes the res. cap is a pressure relief valve. Factory, IIRC, is 14psi while aftermarkets are 16psi.


Possibly there is a good amount of air in the system.
Cap off, let it idle until the therm. opens, turn the car off and let it cool. Put the cap back on.
Yes new 180* stat. I did relive the pressure and let it run for a while, Until it stopped blowing air. Let it cool off and tighten the cap again. I am gonna go start it up again and check. Thanks.
 

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Discussion Starter #4
Start it up with out the cap on. Still getting lots of air. Let it run until no more bubbles. Shut it down and I will let it cool off. I never turned on the heater. Could that hold an air bubble. I did it just now while it was running.I will let it cool off. And try again. Also, If the 2 small hoses that go into the tank at the top, if those were backwards would that cause a problem ?
 

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Are you possibkly hearing any air bubbling while driving the car? I had a silverado (not the same but it worked anyways) that would bubble like a coffee pot while driving and no heat. I was informed of adding coolant til its full to the top with the vehicle running., then drive it for a while (10-15 minutes) and check it. repeat til it stays at the full mark like its supposed to. I dont think the focus has a heater control valve in either hose that goes to the core. if it does, the yes it will matter, otherwise it wont. Water pump will push the water through just the same.
 

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Discussion Starter #7
Yeah, I dont think it has a valve. So the water is pumping through the heater core all the time. Had to go to work. Didn't want to chance it exploding , so I drove the wifes car to work. Won't get to it until Monday. Hopefully its just the hose is old. And can't handle the pressure any more. The shop manual says it should not get above 20 psi. So that's quite a bit of pressure. Probably enough to expand a bad hose. But it sure was a lot of air for a self bleeding system ?
 

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C2H5OH
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Bubbling can be a sign of a blown head gasket.
When you get home pull out the spark plugs, grab the air hose and blow air into the cylinders ... do you see bubbles in the res.?
 

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Discussion Starter #9
I thought that also. But it does stop , after a while. Unless the head gasket is sealing after it gets warmed up ? But I will pull the plugs and check it out.
 

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Discussion Starter #10
Bubbling can be a sign of a blown head gasket.
When you get home pull out the spark plugs, grab the air hose and blow air into the cylinders ... do you see bubbles in the res.?
You were correct. Looks like a Blown head gasket.
Well ,here we go. Upper radiator hose blows up like a balloon. Compression test says 167 psi. Leak down test says gurggle ,gurggle into the coolant tank. Cylinder. # 4 is the culprit. Not loosing any coolant. Not blowing any steam. It was a Cometic head gasket. I have a brand new oem Ford gasket at home. Time to pull the head. I guess that's what happens if you want to play.
 

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You're boosted. Find out what head gasket is going to handle the pressure before you go swapping. I'd have thought that the Cometic would do it, but it might not have been torqued down correctly or the threads weren't cleaned out with a bottom tap. I'll go for that last explanation. You might want to take a long rod and scrape the bottom of the thread hole to see if there's any crud down there. I have no idea how you'll get it out if you do, but I imagine with a shop vac, a roll of duct tape, and some appropriately sized tubing you can figure something out.

It's fairly rare, but it does happen. I can't believe you're going to shoot for a factory gasket though. It might be time to try copper, and double check your plane. I'd ask Turbo Tom what he'd do.
 

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Discussion Starter #13
You're boosted. Find out what head gasket is going to handle the pressure before you go swapping. I'd have thought that the Cometic would do it, but it might not have been torqued down correctly or the threads weren't cleaned out with a bottom tap. I'll go for that last explanation. You might want to take a long rod and scrape the bottom of the thread hole to see if there's any crud down there. I have no idea how you'll get it out if you do, but I imagine with a shop vac, a roll of duct tape, and some appropriately sized tubing you can figure something out.

It's fairly rare, but it does happen. I can't believe you're going to shoot for a factory gasket though. It might be time to try copper, and double check your plane. I'd ask Turbo Tom what he'd do.
Hey Alex, Yeah after some research, it looks like all the really high HP engines are using the OEM HG, go figure, another part Ford did right. I am using ARP head studs , with their assembly lube. And I torqued them in the order in the Ford Shop manual, and in 3 stages to get to the 60ft lbs. Looks like a few other guy`s have had the Cometic experience also. Live and Learn. Got home last night and started the removal process. Down to just taking it off. Be back on the road shortly. My job is getting in the way of all the fun I want to have. LOL
 

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Discussion Starter #14
Does your coolant smell of exhaust fumes as well? Thats a clear sign the HG has gone out as well as your compression test!
Hey whats up ? The coolant didnt smell like exhaust. But every thing is so new and I have an exhaust gas tester for the cooling system at work, but as usual the guy`s I work with left it with no juice . But only cyl # 4 did the gurggling, and you could see into the cyl that it was wet...car still was running fine, at start up it was missing a little, probably a wet plug, after it burned off , it ran great. Not a problem though, be back on the road by Friday. if all my parts show up in time..... Thanks
 

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Discussion Starter #15
Got it all pulled apart. Cyl #4 was all wet. You can see where the gasket failed. Got a new one ready to go. Waiting on a few new pieces from CFM. Should be back on the road by Friday.
 
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