No Heat from Front Heater

[btdaffe]

I know this has been discussed many times before but just want to double check before having my heater core replaced.

Here's my situation right now:

1) Rear heater gets very hot

2) Air flow from front ducts good

3) Hoses thru firewall to front heater core are both very hot to the touch

4) I can reach in and touch the top connection of the front heater core (in the cab) and they are Hot to the touch

5) Heater control valve works (the plunger moves up and down fine)

Still I only get small amounts of heat from the front, and if it's real cold outside I get nothing.

Any ideas?

 

[rusty_tlc]

You could try to back flush the front heater core.

Clamp the two hoses off on the engine compartment side of the fire wall then disconnect.
I made a short hose with a female hose mender on one end then clamped the other end to the return side of the core. (The one that isn't hot now.) Hook up a garden hose and turn on the water. With any luck an amazing amount of gunk will come out of the supply side hard line.

This worked really well in my case. I went from barely feeling any heat to having to set the control mid way to keep from getting to hot.

 

[btdaffe]

I'm going to try the backflush. I'll post my results.

Thanks!

 

[Elbert]

just guessing...restricted heater core.

 

[slcfj62]

The valve on the firewall could also be plugged.

 

[btdaffe]

The core must have some water flowing thru it because the outlet hose is very hot to the touch.

Could a reduced flow of water thru the core really cause me to have little to no heat?

 

[Elbert]

The valve on the firewall could also be plugged.

OP says heater control valve works.

 

[Elbert]

The core must have some water flowing thru it because the outlet hose is very hot to the touch.

Could a reduced flow of water thru the core really cause me to have little to no heat?

Your fan is working right?

Both heater hoses that feed front heater core are hot to the touch after truck is up to operating temp?

Do you know what temp you are running (regarding coolant temp?)

Yes its my asumption that if both hoses are hot at the front heater core that you have flow through the core. But if there is a lot of crap in the heater core it may not be able to radiate heat as required.

You have not done any other work and your rear heater puts out heat fine?

I would double check the heater control valve but it souds as if its working.

Time to flush the system...if that does not work then based on what you've said I would say the heater core needs replacing.

 

[brian]

tagging in with slow heat.

 

[btdaffe]

I'm going to flush core and actually remove and inspect valve tomorrow....let you all know what the status is after that.

Come on Heat!

 

[alaska60]

Your little spring loaded door may have slipped out.
Try this first..
while rolling down the road, turn your fan off and hit the brakes kinda hard........you may hear a door shut. now turn the fan back on and..... walla....HEAT!

 

[btdaffe]

So I back-flushed the front heater core today. I attached garden hoses to the inlet and outlets at the fire wall (with hose mender kits, see photos). The lower hose is the water supply from my faucet, and the upper hose runs into a collection bucket. Ran the water full blast and out came a bunch of black and grey crap. Ran the hose until water ran clear, then reassembled everything. I also checked the operation of the heater valve...worked great.

Well....now I have HEAT! The air from my front vents is ranging around 120 - 140 degrees (it was warm out today though, probably 70).

I've been living with this problem for 7 years...well at least it works now. Hope this will last into the winter.

 

[Elbert]

good news...

would advise you to totally drain the coolant and install new 50/50 mix of distilled water and coolant.

 

[btdaffe]

Sounds like a great idea! I'll do that this weekend. Thanks everyone for the tips.

 

[rusty_tlc]

 

[brian]

so i thought i could wait till spring to jump on this...but the snow and ice keeps coming, and i don't have enough heat to clear the wind shield let alone keep it clear....so tryed this today....no love for me, no ick or anything.
turned out my lines running into the heater are not very warm.
the rad gets warm and the thermostat housing gets plenty warm, but none/very little is making it to the heater core. so i'm going to throw a new thermo and gaskets at it......a working temp gauge would be handy in this case......

 

[sl33py]

Brian - i've also heard good results flushing it with muriatic acid... can be nasty stuff so be careful with it. A rad shop can also do this which might be worth the $ if it helps.

GL!

 

[rusty_tlc]

so i thought i could wait till spring to jump on this...but the snow and ice keeps coming, and i don't have enough heat to clear the wind shield let alone keep it clear....so tryed this today....no love for me, no ick or anything.
turned out my lines running into the heater are not very warm.
the rad gets warm and the thermostat housing gets plenty warm, but none/very little is making it to the heater core. so i'm going to throw a new thermo and gaskets at it......a working temp gauge would be handy in this case......

The radiator should get HOT not warm.

Before you install the new thermostat test the old one, all you need is a pan of water and an instant read thermometer, even a meat thermometer will work. Just heat the thermostat up in a pan of water watch the temp, the thermostat should open up at around 180° or whatever is stamped on the unit. You probably want to do this when is out of the kitchen. If it test okay save a few bucks and return the new one.

My nickle is on a missing upper gasket.