Cold air at idle, blows warm on the highway. Upper rad hose is hot, lower rad hose is cold. I checked the Thermostat (replaced it actually), flushed the rad. Water Pump seems ok because when I take out the thermostat and run the engine, coolant flows through the system and temp stays too cool. thought I might have an air bubble, but after purging the system I still hae the same problem.
Any thoughts would be helpful.
You should have hot water on all rad. hoses when the motor is running at a norm. temp. the water is not going through the heater core like it should. you have cutoff valve bad low water are a stopped heater.try a hoter thermostat if none of the above are true.
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This could be the result of a number of issues, we'll go from least expensive to most. 1) replace your thermostat on the rad. 2) check your coolant level and make sure it is also good i.e. use a tester to measure its temperature range. 3) after the engine has been running for a while, are the upper and lower rad hoses approx. the same temperature to the touch? This is an '05, it is also possible that the heater core is shot.
check and make sure the radiator is full of antifreeze take off the radiator cap and top off the radiator then take your hand and cover the hole where the cap goes and squeeze the top radiator hose a few times to help it go down that way if there is a air pocket somewhere it will help push it out when you thank your done top off again and replace the cap and try
Check that the heater pipe are hot, there are 2 pipes 1 in and 1 out. if both cold could be stat .If 1 is hot and the other is cold it could be air or blocked heater matrix, with car running take cold pipe off . if water flows out check its warm, if it flows out cold leave till water warms up then put pipe back on, make sure you keep radiator topped up while your doing it, if no water comes out when you take the pipe off the matrix is blocked, take both hoses of and flush through with a hose pipe.
You need to check the car t cold start up by checking both the lower and upper radiator hoses. After a few minutes one should be hotter than the other. If not the themostat may be stuck open. also chech to ee if there is heater contro valve from the engine to one of the hoses going to the heater core and see if it actuates by moving the temperature control from cold to warm.
Loosen the cap on the rad and run the engine up to operating temperature. Make sure the rad is full, and go for a short drive around the block to warm up the engine. Make sure the heater is turned on high and the fan running full. There will likely be some burping and gurgling going on as the air gets forced out. Keep checking and topping up the rad. Eventually it will stop.You should run it for acouple days with the cap loose to be sure all the air is out. After that, make sure the rad is full, close the cap and top up the overflow bucket.
ther are a couple of things that would cause this. im assuming that the blower is still working (blowing cold air) .if the blower is still working i would check the coolant level in the rad first. if the coolant level in the rad is good then i would check the thermostat. you can do this by getting the vehicle up to operating temp and checking the upper and lower rad hoses. if one hose is really hot and the other is cold or luke warm i would replace the thermostat. ( watch out for the belts when checking the hoses!) if both hoses are the same temp the thermostat is probably good. from ther i would check the two coolant hoses that are going into the car (you should be able to see them on the passenger side of the engine compartment going through the firewall into the cab). same idea as the two rad hoses , feel the tempeture of the two hoses and if one is really hot and the other is cold or luke warm, then your heater core needs to be flushed out . any more questions just leave a message !
Have you checked for air in the system ? Some of the V-6 engines have an air bleeder on top of the intake manifold to release trapped air. What you do is fill the rad to the top , start the cold engine and open the bleeder untill fluid comes out meaning the air has been vented. With air in the system the heater does not transfer heat efficently. You can also vent an engine by squeezing the upper radiator hose with the engine off and cold. Never open a hot system. The squeeze method is easy. With cold engine remove the cap and fill the radiator almost to where it will spill over. Then slowly squeeze the upper radiator hose and you will see the air escape. When you release the prussure you will see the level drop slightly. Now if you do not have air in that system you will need to check the heater core flow. With everything closed up and full start the engine and let it warm up. Now feel the two hoses in and out of the heater core where it goes thru the firewall in one is cold and one is warm then your heater core is plugged. You can try a flush at this point but it usually needs to be replaced. Thanks for asking at Fixya.com.
WELL IS YOU COOLANT LEVEL RIGHT AND IF SO WHEN TRUCK IS WARMING UP CHECK THE RAD HOSE'S AND SEE IF THE LOWER ONE IS GETING WARM ARE NOT OR IF THE TOP IS COLD BUT I WOULD START WITH THERMOSTAT IT'S SOUNDE LIKE IT IS COUSE FLOW ISUSSE HOPE THIS HELPS BUT IF BOTH HOSE ARE HOT AND YOU TOUCHE HEATER HOSE ONE HOT THE OTHER IS NOT THEN IT COULD BE HEATER CORE ISUSES