My heater on the '85 Brat is blowing too cool. Blows fairly warm at first for about the first 20 t0 30 seconds. I've checked the knobs and cables, all the mechanicals are in working order. i've checked all the hoses Under the hood, and the heater ones under the dash too, they are hot, so water is getting thru so i don't suspect any blockage. No leaks or smell of coolant. Temp. guage is in working order and temp. is where it should be.

 

I am suspecting the waterpump even tho i am getting no leaks or any odd/shouldn'tbemakingthatnoise sounds. i popped the radiator cap and noticed that the coolant appeared to not be circulating but just sitting there. Odd thing is, everything works just fine except for the temp. of the heat comming out of the heater!

i'd pull the heater core hoses and flush the heater core. if it has limited flow it'll can do what you're saying.

 

it heats up enough that it's warm for 20-30 seconds. then when you turn the heat up the demand for heat is greater than the reduce flow can supply...so it cools down.

 

i would expect you to see a change in operating temps if the water pump had limited circulation. for instance pulling hills or long grades.

 

a thermostat stuck open (or removed) will cause the car to run very cool, particularly in the winter/very cold temperatures. it circulates too fast and cools it too much, not allowing the coolant to warm up very much.

 

i was driving an XT6 last winter without a thermostat and the heater couldn't warm up at all. that can cause the same thing, but your temp gauge would probably show a bit lower than normal too.

Heh, i'll try that. PARTIAL blockage never occured to me. I tend to have an all-or-nothing personality.

I tend to have an all-or-nothing personality.

when you solve that problem will you let me know the trick!??!!? i'm really good at that too some times.

My heater s got a similar problem due to the air dam not closing all the way, I have to reach up under the dash to fully close the flap or it blows luke warm air. I think its a hard cable (solid wire in a housing) or something, I havent torn it all the way apart.

Flushed the core, no change. I'll probably take it in for an entire system flush & coolant change. I really hope a new heater core is not in order. My '84 wagon blows damn near SCALDING hot!

Flushed the core, no change.

 

 

Did water flow easily through the core??

 

Does air flow well through the HVAC system?

 

Assuming the above are true and the car runs at normal temperature while driving:

 

With the engine up to operating temp, operate the heater as you described to get the warm air for a short time. Monitor the supply and return lines to the heater core. Before the blower is on, they should be the same temperature. After the blower is on, the return line should be a little cooler - but still pretty hot. If there is some obstruction reducing the coolant flow, the return line should cool way down. Also, check the lines near the firewall, and near the engine. If coolant is flowing normally, they should be close to the same temperature. If the coolant isn't flowing, I would expect to find the highest temps near the engine, coolest near the firewall. If you're not sure what the temps should be, compare to your other car.

 

Also look at the air dam controlled by the temperature setting on the heater control panel. It directs air through the core or around it.

 

About not seeing circulation in the radiator cap: With the engine not under load, the thermostat will only open ocasionally, so you would have to watch for a while.

My heater s got a similar problem due to the air dam not closing all the way' date=' I have to reach up under the dash to fully close the flap or it blows luke warm air. I think its a hard cable (solid wire in a housing) or something, I havent torn it all the way apart.[/quote']

 

+1 sounds like a blend door stuck

On my 81 brat there is a tiny little valve on the hose that goes to the heater core. My brat has been sitting for 5 years I got it to half way run saturday. I was sittin in the seat just letting it run and noticed water started running all over my shoe. The only reason i noticed the valve is because I had replace that hose. Just an Idea. If ours are the same it would be worth taken a look before replacing the core.

 

Note: on mine one end of the hose it about 1/2 and the other end is about 7/16. Dont destroy the hose because it tapered.

 

Good luck

Kelly

I believe the "blend door" mentioned is

for the EA82 series cars

 

the EA81 this gentleman has, uses

a coolant flow control valve

to adjust the temp of the air

coming from the heater ducts.

Sorry just thought I could help

1. Checked all my controls, everything is properly adjusted and working correctly.

 

2. All hoses, inside and at the firewall, are very hot and stay that way thru all settings.

 

3. Not sure how easily coolant is supposed to flow thru the core, but it does flow. Will pop the hoses on the wagon and see if the flow is any different.

 

4. Thanks for all the imput guys!

 

2. All hoses, inside and at the firewall, are very hot and stay that way thru all settings.

 

If by very hot you mean very close to engine temperature, coolant must be flowing.

 

That would make me think somehow the air isn't getting through the core. Or the core has none of the fine fins left.

I believe the "blend door" mentioned is

for the EA82 series cars

 

the EA81 this gentleman has, uses

a coolant flow control valve

to adjust the temp of the air

coming from the heater ducts.

 

Ok I am not familar with these cars. But the airflow could be restricted in another way.....maybe dirt and lint on the core itself...just a thought.