Heater not working now

[Automan1988]

I have a 1991 ranger with a 2.3 and just installed a new water outlet housing, 192* t-stat and heater hoses. The truck is not getting up to temp, and the heater is blowing cold. The only way I can get any heat out of the heater is to rev the engine up and then you can feel it start to blow warm, but not like it should be, and as soon as you let off the throtle the heater cools back down. It has a coolant flush kit on it and when I loosen the cap coolant is dumping out so I know that there is flow in the system. Any ideas on why it will not warm up or blow warm air.

 

[Mark_88]

You have an air lock in the system...it needs to be burped...let the engine cool...remove the rad cap, run the engine for five to seven minutes with the rad cap off...turn the heater fan on high and put it on defrost or panel so it's easier to feel the heat...

You should see the fluid rise up and then drop...once the fluid drops, top it up to just below the cap and then put the cap on...it should blow hot after that...

Had the same thing on both my trucks recently after working on the cooling system...just make sure that your coolant is not mixed too strong because the stronger it is, the less likely it will reach proper temps...and too strong is actually not good for the cooling system.

 

[kimcrwbr1]

Another possibility is to remove the cap on the flush fitting with the engine off hold is as high as possible and slowly pour water in until it is full and put the cap back on. I have also hooked the hose up on the flush fitting ans start the motor. remove the radiator cap and turn the hose on slow until coolant starts to come out the radiator. You will know hen you have it if both hoses going to the heater core are good and hot. I have also had a nipple on the bypass hose plug up that will also keep coolant from circulating through the heater core unless the thermostat is open. Another possibility?

 

[kimcrwbr1]

http://www.autozone.com/autozone/parts/1991-Ford-Ranger-2WD/Hose-Bypass/_/N-itubdZ9pdm6 pull the bypass and clean out the nipples a new hose wouldnt hurt either it allows the engine to warm up properly.

 

[RonD]

Engine not getting up to normal temp is odd.
The function of the T-stat is to make the engine run at 200-230deg, it is more efficient that way, it's not to make the heater warm up faster, lol.

How is the fan clutch, it should be loose, spin fairly easy, and quiet when engine(clutch) is cold then start to get tighter(pull more air thru rad) and louder as it warms up.
If the fan clutch is locked or tight all the time it would cool the rad more, but T-stat should close a bit to keep engine temp up.

Heater core could be partially blocked, when engine is warm and heater on, feel both hoses, one will be warmer, that is the input hose, the other should be only slightly cooler that is the return hose.
If it is a lot cooler then core has limited flow, could be the regulator not opening all the way but could be build-up in the core.

You can use a garden hose or compressed air on the "return line" to back flush the core.
The "input line" needs to be pointed down at the ground or in a bucket you don't want to blow stuff all over the engine or back into the cooling system.
Make sure regulator is open full if you do this.

 

[adsm08]

Another possibility is to remove the cap on the flush fitting with the engine off hold is as high as possible and slowly pour water in until it is full and put the cap back on.

This is a good way to fill it.

The way I do it on the non-degas bottle 4.0 SOHC is to fill the rad and then take one heater hose off the heater core and jam a spill-free in it, then fill until it starts to come out of the heater core.

Never have bubbles in the system that way.