No Heat
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No Heat
I have a 2000 F-250 5.4L with just over 100k miles. I changed the heater core last year due to a leak. Heat worked fine until 3 months ago. I was letting it warm up on a cold morning and after getting in noticed the temp guage was maxed out. I shut it off and checked under the hood and the top hose was cold with only slight pressure. After opening the overflow cap the thermostat opened and the water went through and the temperature came down. I figured I should replace the thermostat (and did the next day) but the truck ran fine the rest of the day. It was a couple of days later that I realized the heat wasn't working. I have flushed the system and water will go throught the heater core in both directions and seems to flow thrrough the rest of the system too. I still have no heat at all. Checked the blend door and that works fine. Checked it on vent mode and still no heat. What else can I do?
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There is not even the slightest heat. After 30 minutes on the road it blows cold air. I am loosing coolant somewhere although it isnt a constant leak as there is no sign of leaking where I park. I put a flush kit T into the line from the heater core to the back of the block and when I put water through it it flows fine both directions (I clamp off the hose on either side of the T to restrict the direction).
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Joined: Jun 2004
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From: Apex, N.C.
Are your heater hoses getting warm after the truck warms up?
What is the condition of the pressure cap?
It seems to me that you are not getting all of the air out of the cooling system causing the above problems. Is your top radiator hose higher than the radiator anywhere? If so fill the degauss bottle and take the truck around the block and get it good and warmed up with the heat wide open. When you park the truck, park it on a hill(steeper the better) nose up. Shut it off and let it cool down. Repeat this a few times and see if the water is going down in the degauss bottle as the system sucks coolant into the cooling system.
If you really do think that you have a leak, pressure test the system. A weak water pump will also cause a "no heat" scenario.
Good luck, and keep us posted.
What is the condition of the pressure cap?
It seems to me that you are not getting all of the air out of the cooling system causing the above problems. Is your top radiator hose higher than the radiator anywhere? If so fill the degauss bottle and take the truck around the block and get it good and warmed up with the heat wide open. When you park the truck, park it on a hill(steeper the better) nose up. Shut it off and let it cool down. Repeat this a few times and see if the water is going down in the degauss bottle as the system sucks coolant into the cooling system.
If you really do think that you have a leak, pressure test the system. A weak water pump will also cause a "no heat" scenario.
Good luck, and keep us posted.
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There doesnt appear to be any kind of valve or switch in either line to the core.
I have had air in the core before and it is noticable by the gurgling noise under the dash on the passenger side but this is not happening now though. The hoses do get warm but not as hot as the top hose from the radiator to the thermostat, which is higher than the overflow. The overflow cap seems to be ok but is this a possible place for the fluid to leak out? Shouldnt the pump push the water through the system even without pressure such as when the cap is off? Is there any way to see if the waterpump is working properly? I have been putting on alot of miles recently and haven't had excessive heating, the guage starts on cold and goes to just over halfway to hot.
Thanks for the help.
I have had air in the core before and it is noticable by the gurgling noise under the dash on the passenger side but this is not happening now though. The hoses do get warm but not as hot as the top hose from the radiator to the thermostat, which is higher than the overflow. The overflow cap seems to be ok but is this a possible place for the fluid to leak out? Shouldnt the pump push the water through the system even without pressure such as when the cap is off? Is there any way to see if the waterpump is working properly? I have been putting on alot of miles recently and haven't had excessive heating, the guage starts on cold and goes to just over halfway to hot.
Thanks for the help.
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From: Burnsville, MN
Shouldnt the pump push the water through the system even without pressure such as when the cap is off?
If you have a radiator cap on your radiator, and its off while the engine is warmed up and running, you should be able to see water in motion.
(Obviously you have to be careful if you remove the cap after the engine warms up...!)
If you can't see any moving coolant with a hot engine, you'd have to suspect the water pump or thermostat I'd guess....
If you have a radiator cap on your radiator, and its off while the engine is warmed up and running, you should be able to see water in motion.
(Obviously you have to be careful if you remove the cap after the engine warms up...!)
If you can't see any moving coolant with a hot engine, you'd have to suspect the water pump or thermostat I'd guess....
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Water Pump Deteriorated
Thanks for all the help. Had a radiator guy look at it with me and the coolant was not circulating well at all but pressure tested the system (while not running) and it did NOT lose pressure. I replaced the water pump myself and found that the blades had deteriorated/rusted out almost completely so there was no sign of rhe raised fin, just a sharb pointed blade. The water was leaking out of the radiator cap because of excessive pressure. Now I have heat again but have confirmed that exhaust is leaking into the cooling system and creating pressure which causes the coolant to come out from the cap.
Now I have a head gasket issue or more likely a warped head(s) likely from overheating months ago since the waterpump wasnt circulating while I left the truck to warm up on a cold morning.
I have gotten quotes from $900-$1700 just to remove the heads and check them for warpage then put them back if they are ok. If the heads are warped, what then, a new engine or just new heads?
Now I have a head gasket issue or more likely a warped head(s) likely from overheating months ago since the waterpump wasnt circulating while I left the truck to warm up on a cold morning.
I have gotten quotes from $900-$1700 just to remove the heads and check them for warpage then put them back if they are ok. If the heads are warped, what then, a new engine or just new heads?
