Ok... i have done a lot of troubleshooting here to resolve a heat issue with my Ford F150. I am 100% sure the issue is not under the dash. The issue is i am not getting any water or very little through the heater core. I have removed both hoses going to the going to the firewall(ie return hose and entry hose coming off the engine). I flushed back and forth several times until water was clear and did this on 2 or 3 occassions. I pulled the return hose comeing from the heater core and put it in a bucket. I turn on truck to see if water would flow. The water trickled until it finally just stopped. Finally i decided to put a spare hose on the point coming from the engine and run the other end to a bucket. At first i got some water to flow but seconds after that burst the water started to trickle and then became small squrts until finally no water at all. The hose did warm up to about luke warm. Also there was still plenty of water in the reservior. The truck never runs hot and temperature stays consistent. I have not power flushed the water system yet. Should i look at changing the thermastat or would it be the water pump. Or should i power flush before changing any parts. When the truck is running, i can pull the cap on the fill/reservior tank and i do see water coming back up into the tank. Its not air because no bubbles.

Thanks

 

maybe the heater core is plugged and the water is moving normally thru the pump / thermostat / motor for cooling. If the temp gauge is normal (warm), the motor does not overheat, and you see movement in the top tank, i might consider a plugged heater core. What if you connect the two heater hoses together with a clear tygon hose to see if there is flow. Maybe pull the heater hose off at the opposite end from heater core and see if the barb fitting is clean and open ? How about holding both hoses up toward the hood above the heater core.. fill it with lime-away or something like that and let it set for an hour, then flush with a hose..(but you think the core itself is clean ?)

 

thanks for reply Steve.... I have flushed with water hose the core in the direction of the normal flow and also flushed backwards. this was with both hoses going to a bucket to catch contaminants. It flushes clear and clean each time. I mentioned in my original post about placing a tube on the outlet from the motor. This means i completely took the heater core out of the picture. The water had an initial flow but quickly went to a drip and then stopped flowing. Its almost as if something is not propelling the water through the system.

 

Well, that means there either isn't any fluid in there or the pump isn't working any more (eroded impeller, usually).

 

Thanks projectSHO89....exactly what i was thinking about the eroded impeller... I saw another post on the forum referring to water pump impeller. I changed out thermostat last year so i guess time to change water pump.