sixt5

well my heater is blowing cold air. sometimes it will get luke warm but thats about it.
things i have checked/done:
new water pump
new t-stat
flushed radiator
flushed heater core (forwards and backwards)

ALL hoses are full and have great pressure. When we flushed the heater core, the flow was excellent and crystal clear, same with the radiator. you can feel the heater hoses get hot. i suspected the valve up on the firewall. so i took the hoses off and i could see the valve open and close. I checked the heater control unit and they are operating the cables they are attached too.

What am i missing?? its getting awfully cold here!!

sixt5

also, i had some air in the system. i got some pretty big pockets out of the system. Then i read to put it up on some ramps so the cap is the highest point. it worked VERY well and i have went through a lot of coolant from the big burps.

abecedarian

assuming the engine is reaching normal temps, the prime suspects would be any coolant passages / hoses that lead to or from the heater / engine or the thermostat is sticking open.

sixt5

its running at normal running temperature (half way on the gauge). i've let it run for 15-20 minutes idleing and drove it a couple of miles and it doesnt overheat.

since there is coolant running through the heater core (we know this by flushing it, there is a solid stream coming out of the return hose) and the blower motor is running fine, i really dont know what else is apart of the heater system. is there any electronic features that shuts off the heater?

abecedarian

from the heater back to the water pump is plugged maybe?

darksoldier313

id say if your flow is good as u say id suspect blend doors or duct working to be malfunctioning sometimes what looks like full operation of levers is only part have the same problem with mine if u watch the cable looks like it fully operates does it blow as hard in hot as it does cold?? does it blow harder from vent to floor to defrost??

vital22re

iTrader: (2)

sorry stupid thing posted twice

vital22re

iTrader: (2)

tear apart the heater box, try touching the heater core. Is it hot when you have the heater on? Maybe its not properly radiating heat. There also might be a flap inside the box that isnt' switching open when you change the heat setting. Just a thought.

idanity

the core itself may be full of sediment.
mine smelled like a dead dog (after fully cleaning the interior) and only after replacing the heater core itself did i get
1. nice new car smell.
2. heat (yes, at 125 + degrees)

after years of p.o.'s dumping radiator seal or just gunk. it may be time to replace that thing.
i would like to cut my old one in half just to see whats inside (but i would also need a protective/ microbe proof suit)...

try all the cheap stuff 1st, as the h.c. is a pita to swap out (esp if you have A/C)

sixt5

i dont believe the core is the problem. when we flushed, the water was crystal clear and was a solid stream of water.

Can i check those flaps without taking the heater box out of the truck? such as taking the glove box part of the dash out?

vital22re

iTrader: (2)

drop the glove box for sure and sneek a peak. there are 2 cables that control the heat one runs out to the valve the other attaches to a flap in the box by the heater core that opens up gradually as you move the setting to hot. And also slowly closes as you change it to cold. sometimes the cable gets kicked off by the passenger. Hopefully the the door didn't lock up break because someone forced it.

idanity

the core can be clogged..and water will be clean..
it can sit like lead in the bottom of your core..

my new core weighs about 3 oz.'s..and the old one wieghs about 45 lbs..

i flushed mine, (w/water) and it too was / looked clean..

to do a proper flush, you have to use ACID...and bathe the core..not just flush..,

89whitetoyota

Check the heater valve on the inside of the engine bay, the little plastic box that the right heater hose goes in to. Take the heater pipes off both sides and look into make sure it isnt stuck closed like mine was. The actual cable from the hot/cold selector was boun dup or broke, so I just manually switched it to run full heat the whole time.

89whitetoyota

I did my heater core about 2 months ago, first time ever doing it, did it but it is a mu fu kka. You have to drop the sterring colomn and take every single thing off the dash to get to it. If it is cleaned out and flowing good, and not cracked (coolant in the floor), i think its something else.

Also, I know you said you did a new t-stat, sometimes you can get lemons with those things, so do the drop in boiling water test and see if it opens right.

timmytoyota

I agree with 89whitetoyota,the heater valve is probably not closing all the way when you move selector into the"red zone"