Heater Problem

[Cor86sr5]

Hi All,

I have a 1986 corolla sr5. A year and a half ago, the lever adjusting the proportion of hot air coming in failed. A service station very cheaply fixed

things into position so that only hot air would come through i.e. so I'd always

safely have defrosting action. (It was a $30 vs. $200 fix for a umm...seasoned car)

Recently, I stopped getting hot air coming in; all is cold. The vent is not in the recirc position and the air NEVER comes in hot (unlike a recent similarly themed thread).

Any advice on where/how I might look for the problem?

Thanks in advance.

All the best.

[daktari]

Sounds obvious i know. But have you checked the coolant level?

[Cor86sr5]

I just checked the coolant on your advice; it is full. (I expect if it was low the

engine would overheat). Thanks much for the response.

[ems]

Try changing your thermostat. That may take care of your problem. If that doesn't work you may have a clogged heater core. Good luck. I hope the thermostat fixes the problem.

[Cor86sr5]

Hi EMS,

Thanks much. A few questions though?

If the thermostat was bad wouldn't the engine overheat?

If the heater core is blocked could it perhaps be flushed out?

If I need to replace the heater core, I see I can get one on-line from $70-$90.

Is it a real hard to replace on my car? (I've been checking on line; it seems on

some cars the core is below the raadiator and on others....it's in the dashboard!)

Thanks so much for the advice.

All the best!

[ems]

Hi cor86sr5. O.k. I'll try to answer all your questions one by one.

1st. The engine would not necesarily overheat. It could be stuck open or shut. If it is stuck open the car would stay really cold. If it was stuck shut it would overheat.

2nd. It is posible to flush out. I actually achieved this on a car that had it clogged. It took lots of patience and also some know how of what you are doing.

3rd. It can be very difficult. If your car has A.C it is more difficult. The job usually involves removal of the dash but, I am not sure on your car. It is not a fun job. I have to fix one on may friends car and we are not looking forward to taking apart the dash on his car.

Any other questions feel free to ask.

[Cor86sr5]

2nd. It is posible to flush out.  I actually achieved this on a car that had it clogged.  It took lots of patience and also some know how of what you are doing.

[

Hi ems,

Thanks again; I'll take you up on your offer to answer more questions.

Apologies for my ignorance.

1. If my thermostat is stuck in the open position, should water/coolant

circulate immediately on starting the engine as opposed to only after

the engine heats up? or....

2. (Related to above) Does coolant flow through the heater core even when

the thermostat is closed? If so, will I want to keep the thermostat closed so

as to get a better flow rate through the heater core by keeping the rest of

the engine out of the loop during the flushing process? That is, will I want to

let it circulate until the engine warms up then shut it off, let it cool and keep

repeating the process?

3. Does revving the car speed the flow rate of coolant through the system?

4. I was going to use a radiator flush product (one advertised for neglected

systems) and water. Do you have any specific suggestions as to what I

should use).

My questions are based on trying to read deeply into what you mean by patience

and know how. So please elaborate with any specific advice. I have since learned

that the labor to replace the heater core on my car would be substantial and,

as you've noted, is an unpleasant job.

Thanks again for the help!

All the best!

[ems]

Hi Cor86sr5. I'll try to answer all your questions so lets start.

1st. If the thermostat is open all the time the coolant will always be flowing throught the engine and keep you engine cool. Not good if you want heat inside. The coolant will flow immediatlely at start up.

2nd. Actually I am going to answer this question a bit more different than you may have thought. I actually unclogged the heater core by directly adding the radiator flush directly to the heater core. I did this by going to the lines that supply the coolant directly to the hearter core. These lines are easy to find because they are attached to the fire wall of the engine bay and go directly inside the car. There should be 2. I unhoocked both lines and poured really hot water into it. I actually boiled the water and just kept watching it pour out from the other line. I then added the radiator flush and let it sit for a while. I then boiled more water and kept adding it until I was satisfied the the water was coming out clean and with force. It is easy you just have to find the lines. Be careful dont get burned. This processed worked well for me and doesn't take long.

3rd. Yes revving the engine makes the coolant flow faster.

Good luck and let me know what happens. Also any questions are welcome.

[TOYMOTA]

When I ran out of coolant in my '87 Rolla GTI, I had no hot air at all. Also had blue smoke coming out the exhaust. I drove it the 15 miles home like that. That was when mine had done 115k miles. i just topped it back up when cold and the car did another 50k before I smashed it. Engine was still fine.

[Cor86sr5]

Hi ems....

I changed the thermostat; I don't think it was defective. I just put

in some flush stuff and now I'm supposed to drive for about 6 hours

while singing to the car. While running the car I think I feel a very

small amount of heat coming out. I'll let you know what develops.

Thanks again!

Hi Toymota....if there's no coolant going thru your heater core carrying heat

I guess that'll happen. Maybe the engine got so hot the oil lost lots of viscosity

and seeped into your cylinders to produce the blue smoke. The reason you were

able to get home is that those corollas are not allowed to strand you away from

home. I've had some strange rides in my corolla....axle bearings gone

bad (so that braking stays braking)....cruise control cable snagging the

accelerator arm (so accelerating stays accelerating....on ice yet), but I

always got home.

Best to all.

[Cor86sr5]

I'm still trying to drive enough with the radator flush in my system. I mean in my car's coolant system.

Questions....

1. If I try blowing out the heater core with compressed air from a gas station could the resulting introduction of oil into the system be a problem? (Oil from the compressor pump)

2. Maybe try hosing it clear with a highish pressure nozzle/from a garden hose?

3. As I stated in my first post, the heater/AC adjustment lever broke and was

set in the all hot position as a cheap fix about a year and a half ago. Could this

have come somewhat undone via jarring of the car...or something?

Thanks in advance and best to all.

[ems]

You should not be driving around with the flush inside your system. You should just follow the instructions and get the flush out of your system. Why dont you do as I told you above. It worked for me. I just flushed the heater core.

[Cor86sr5]

You should not be driving around with the flush inside your system.  You should just follow the instructions and get the flush out of your system.  Why dont you do as I told you above.  It worked for me.  I just flushed the heater core.

←

The instructions said to drive for six hours with the flush in the system.

I haven't gotten there....haven't had a chance, yet. Is it harmful for

the stuff to be in the system?

After that, I intend to follow your advice. One thing a friend pointed out

to me...the intake (i think) to the heater core has a valve on it...looks like

a pin that can go in or out. Could that be faulty? Just thinking of the

possibilities that could be involved.

[ems]

It could be harmful so, I would take it out as soon as you can. I guess that pin could be the problem. If it is what I think it is it is probably the valve that controls how much heat enters your heater core.

[Cor86sr5]

It could be harmful so, I would take it out as soon as you can.  I guess that pin could be the problem.  If it is what I think it is it is probably the valve that controls how much heat enters your heater core.

←

Thanks ems.

The problem had to wait 'till I drove to Baton Rouge (on my way to NYC) where I had

tools, friends and a long time friendly mechanic. The problem turned out to be a lever

accessed by merely removing the glove compartment (behind which I found some long

lost stuff). The lever controls whether or not air goes over the heater core, I imagine.

My friendly mechanic clamped it in place since it keeps vibrating downwards. ..no charge

'till I forced a twenty on him. I had a warm and toasty drive into NY.

Sorry for my long silence.

Best.

....Andy