heat problem - no heat just changed the core
#1
#3
Air in the system maybe around the thermostat not allowing it to operate and open at the right temp. Or bad thermostat. Did you do a full coolant drain before the core replacement? And during the fill, wait for it to get to operating temps before purging the system and topping it off.
Last edited by Toyz; 11-30-2010 at 11:32 PM.
#7
Like mcolford said, change the thermostat for good measure, and then follow the procedure below to "burp" the system.
Run the engine with the heater on high (very important) until the radiator fan cycles. Then shut it down and add anti-freeze as needed. Then bring it back up to temp(fan cycles) and double check the coolant level as a precaution.
Run the engine with the heater on high (very important) until the radiator fan cycles. Then shut it down and add anti-freeze as needed. Then bring it back up to temp(fan cycles) and double check the coolant level as a precaution.
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#9
#10
Just keep in mind, running it like that creates hot spots thru the heads. They can warp/crack that way.
#14
Water Pump
Thermostat replaced, system flushed, still no heat. I'm at the point that
the only thing left is the water pump. Could it be worn enough to cool the engine but not push water up to the heater core? The pump's got 270K on it with no leaks or noise or overheating just no heat.
Mike
#15
Did any one find and answer to the no heat problem? I have a 99' with the 4.6 and am at my wits end as to what to do next. I have replaced thermostat (changed to a hotter one), changed water pump, flushed system 3 to 4 times, heater core has been burped and has proper flow (just no heat). Checked the blend door, actuator motor, replaced temp. control, checked vacuum lines (used vacuum tester inside the cab and under the hood). Top heater hose from radiator checks at 110 degrees after 40 mile trip and bottom runs around 88 degree. When you park after a trip you can touch the block and hoses without being burned. The block will not heat up. I am at my wits end with this truck I even went as far as putting cardboard in front of the radiator to check the fan clutch and it still runs cold! Please, any ideas welcome!!