No Pressure In Coolant System and Not Overheating?
- Thread starter tony1679
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Ok so based on all of your responses, I am down to a cracked coolant tank, water pump failure (multiple definitions of failure), and air trapped in the system.
Well I will go above and beyond to prove each theory wrong or right. But my initial thoughts are:
I can't possibly imagine a cracked coolant tank. There are no leaks anywhere. Not even small. But I will check this. I'm not ignoring anyone or any idea. I appreciate all thoughts and help, seriously. Air trapped in the system, maybe. Although I would think several days of the front end being up on ramps would bring any air to the highest point, the open cap. I think this could be a suspect. I'll look over the link and try again. Water pump, maybe. I'm torn on this one. Part of me says no way, it would overheat if it was. But the other part says yeah it is the problem, there is minimal flow or pressure.
Also, nobody mentioned a restriction or clog. Am I free of these two problems? Once again, thanks for all the help.
Well I will go above and beyond to prove each theory wrong or right. But my initial thoughts are:
I can't possibly imagine a cracked coolant tank. There are no leaks anywhere. Not even small. But I will check this. I'm not ignoring anyone or any idea. I appreciate all thoughts and help, seriously. Air trapped in the system, maybe. Although I would think several days of the front end being up on ramps would bring any air to the highest point, the open cap. I think this could be a suspect. I'll look over the link and try again. Water pump, maybe. I'm torn on this one. Part of me says no way, it would overheat if it was. But the other part says yeah it is the problem, there is minimal flow or pressure.
Also, nobody mentioned a restriction or clog. Am I free of these two problems? Once again, thanks for all the help.
Originally Posted By: tony1679
Water pump, maybe. I'm torn on this one. Part of me says no way, it would overheat if it was. But the other part says yeah it is the problem, there is minimal flow or pressure.
Heat creates the pressure, not flow... Also if pump were weak there generally isn't enough flow to push coolant through the heater core, return hose will be noticeably cooler than inlet hose...
Other than maybe a weak cap and issue with the heater it's self, I don't think there is a problem...
Water pump, maybe. I'm torn on this one. Part of me says no way, it would overheat if it was. But the other part says yeah it is the problem, there is minimal flow or pressure.
Heat creates the pressure, not flow... Also if pump were weak there generally isn't enough flow to push coolant through the heater core, return hose will be noticeably cooler than inlet hose...
Other than maybe a weak cap and issue with the heater it's self, I don't think there is a problem...
Originally Posted By: Garak
Well, this may be a job for a pressure test then.
Correct. Some simple things to check, make sure all the clamps are tight. Also check the temp of both heater hoses. They should both be very warm with one being slightly cooler than the other. Your Ford uses a blend door in the heater box, make sure it is functioning if the heater hoses are hot.
Well, this may be a job for a pressure test then.
Correct. Some simple things to check, make sure all the clamps are tight. Also check the temp of both heater hoses. They should both be very warm with one being slightly cooler than the other. Your Ford uses a blend door in the heater box, make sure it is functioning if the heater hoses are hot.
Yep, if the cap isn't leaking, and it's not spewing out coolant somewhere, something else is leaking slowly enough to ensure pressure won't build up.
^^^ this. If it's reaching 200F and there's no pressure in the system, there is a small, slow leak. It might not be an issue at all with around-town driving and regular top-offs, however, it could be a real problem on extended drives.
It's also possible the leak is in the upper part of the expansion tank, so it's failing to build pressure but not losing coolant.
I would check the blend door.
Originally Posted By: zzyzzx
I would check the blend door.
I'm still confused on this. Does this touch air or coolant?!? If it is restricting coolant then this is definitely possible. If this only controls air flow, this is completely irrelevant. Clarification please?
Also, another update, I am 99.9% sure there aren't any cracks in the tank. I removed the bolt and was able to lift it up several inches and used my camera to check where I couldn't see. I didn't want to drain the fluid again... No cracks were found. Also when I squeeze both radiator hoses when it is cold I hear and see coolant gurgling in the overflow tank. So this confirms there is not a clog in the radiator and hoses.
I'm leaning toward a water pump issue at this point...
I would check the blend door.
I'm still confused on this. Does this touch air or coolant?!? If it is restricting coolant then this is definitely possible. If this only controls air flow, this is completely irrelevant. Clarification please?
Also, another update, I am 99.9% sure there aren't any cracks in the tank. I removed the bolt and was able to lift it up several inches and used my camera to check where I couldn't see. I didn't want to drain the fluid again... No cracks were found. Also when I squeeze both radiator hoses when it is cold I hear and see coolant gurgling in the overflow tank. So this confirms there is not a clog in the radiator and hoses.
I'm leaning toward a water pump issue at this point...
Originally Posted By: rslifkin
It's also possible the leak is in the upper part of the expansion tank, so it's failing to build pressure but not losing coolant.
....Interesting. Somehow I didn't think about this. I guess the way to eliminate this variable is to overfill it completely, then check for leaks. I will try this with some distilled water, coolant is beyond compromised and needs flushed anyway. Thanks!
It's also possible the leak is in the upper part of the expansion tank, so it's failing to build pressure but not losing coolant.
....Interesting. Somehow I didn't think about this. I guess the way to eliminate this variable is to overfill it completely, then check for leaks. I will try this with some distilled water, coolant is beyond compromised and needs flushed anyway. Thanks!
Blend door only directs air, has zero effect on coolant flow... It's failure is generally the motor that operates door or in some instances the door may be stuck or broken(isn't much more than a plastic flap)... As I posted earlier if it has the auto temp(ETAC) system, it WILL have stored a trouble code...
Originally Posted By: TFB1
Blend door only directs air, has zero effect on coolant flow... It's failure is generally the motor that operates door or in some instances the door may be stuck or broken(isn't much more than a plastic flap)... As I posted earlier if it has the auto temp(ETAC) system, it WILL have stored a trouble code...
Thanks for clearing that up, it's what I was thinking, but wasn't positive. And again, regarding my lack of heat, I'm 99.9% sure either the motor or the door is the problem. But I'm solving one problem at a time, eliminating one variable at a time. But it does have the auto temp system (can control what temp the interior is digitally, 70/71/72 degrees). I will try to have the codes read before tearing into that can of worms. I just felt the coolant pressure was more important, and needed attention first. Thanks again.
Blend door only directs air, has zero effect on coolant flow... It's failure is generally the motor that operates door or in some instances the door may be stuck or broken(isn't much more than a plastic flap)... As I posted earlier if it has the auto temp(ETAC) system, it WILL have stored a trouble code...
Thanks for clearing that up, it's what I was thinking, but wasn't positive. And again, regarding my lack of heat, I'm 99.9% sure either the motor or the door is the problem. But I'm solving one problem at a time, eliminating one variable at a time. But it does have the auto temp system (can control what temp the interior is digitally, 70/71/72 degrees). I will try to have the codes read before tearing into that can of worms. I just felt the coolant pressure was more important, and needed attention first. Thanks again.
Originally Posted By: TFB1
Blend door only directs air, has zero effect on coolant flow... It's failure is generally the motor that operates door or in some instances the door may be stuck or broken(isn't much more than a plastic flap)... As I posted earlier if it has the auto temp(ETAC) system, it WILL have stored a trouble code...
I do not think anyone did say it affects coolant flow.
You mentioned both heater hoses are warm so the heater core is warm, I would bet the blend door is not operating. A lack of pressure will not keep your heater from working. Do a pressure test for your lack of pressure!!
Blend door only directs air, has zero effect on coolant flow... It's failure is generally the motor that operates door or in some instances the door may be stuck or broken(isn't much more than a plastic flap)... As I posted earlier if it has the auto temp(ETAC) system, it WILL have stored a trouble code...
I do not think anyone did say it affects coolant flow.
You mentioned both heater hoses are warm so the heater core is warm, I would bet the blend door is not operating. A lack of pressure will not keep your heater from working. Do a pressure test for your lack of pressure!!
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Codes are easy to read, the EATC head has self diagnostics, just need to press correct combinations of buttons to start test(sorry but I have my shop manual loaned out)...
If you want to learn about your car, hang out over on CVN(Crown Vic Net)...
If you want to learn about your car, hang out over on CVN(Crown Vic Net)...
There is no heat and the heater lines are empty according to Tony. The heater valve can be by passed with a straight piece of pipe.
Originally Posted By: WobblyElvis
There is no heat and the heater lines are empty according to Tony. The heater valve can be by passed with a straight piece of pipe.
Could you enlighten us as to where this heater valve is??? I've owned six Grand Marquis and none of mine had one...
Posts such as this is why one is far better off visiting a dedicated forum for said vehicle...
There is no heat and the heater lines are empty according to Tony. The heater valve can be by passed with a straight piece of pipe.
Could you enlighten us as to where this heater valve is??? I've owned six Grand Marquis and none of mine had one...
Posts such as this is why one is far better off visiting a dedicated forum for said vehicle...
I don't own one of these engines but autozone lists one for this vehicle.
If you know you have an issue with the blower or blend door, fix that first then get back to us. Almost always fix the known issue first.
Update - I rented a coolant pressure tester. I first checked the old cap. It wouldn't hold any pressure at all. The new one holds steady. Then I attached the pressure tester in place of the cap, pressurized the system, and left it for an hour. When I returned, it was exactly where I left it, 16psi. Both radiator hoses were solid as a rock, as well as both heater core hoses. I am not calling this proof, but rather a good indicator that there aren't any clogs in the system.
So if the system holds pressure, the cap is proven to be good, the thermostat seems to be working properly, and heat (but not pressure or flow) is being distributed throughout the system, what is wrong?
Surely this has to be the water pump...?
So if the system holds pressure, the cap is proven to be good, the thermostat seems to be working properly, and heat (but not pressure or flow) is being distributed throughout the system, what is wrong?
Surely this has to be the water pump...?
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