HELP! its cold and heats not working

[Jamz SHO 813]

Hello everyone. I have a 93 MTX and a problem. Just recently the heat has not been working properly. I usally put the vent on and within minutes it will usally pump lots of hot air. Now, only freezing cold air comes out. I have tried putting it on defrost, floor, panel and floor it only blows cold. After a good half an hour or so of playing with it I'll start to feel a little warm air come out and aout 45mis later its all heat. Here is just some facts to help I replaced thermostat and water pump at 60k. The belts squeak bad when max A/C, deforst and Auto come on. The squeaking will stop but continues a few minutes later. Also I was in an accident in Sept. and the whole bumper radiator and support were replaced. I hope this helps you to help me because I am stuck and freezing.
Always Greatly Appercaited!!!
HAPPY TURKEY DAY!!! GOBBLE GOBBLE GOBBLE

 

[Slo-Sho]

Have you checked your coolant level?

 

[Jamz SHO 813]

No I have not yet but I will shortly. My g/f called just before and said that i left a puddle in her driveway. She said its not oil but it looks like water. Also the other day just out of no where the overflow tank started spitting out coolant! I didn't have the a/c on or anything. A few minutes later it stopped. Any ideas on how to fix the squeaking belts? Also the car had 97k on it.
Thanks for the quick reply slosho

 

[Slo-Sho]

If they are loose, simply tighten them. Otherwise they may just need replacing. I'd check that coolant level quickly, the cooling system is critical to engine life.

 

[Jamz SHO 813]

Just took a look and the coolant is way above the yellow line. Maybe there is too much antifreeze in there? I have no idea...
Thanks for helping though slosho

 

[BeatDaSHO]

The squeak is probably not from your belts but from your A/C compressor clutch. That is why you hear it come on and off. You mentioned that you did the 60k but u didn't tell us when u did it ( how many miles were on your car at the time). I would replace your thermostat again and get the motorcraft 192 degree thermostat.

Greg

 

[SHOZ123]

Just took a look and the coolant is way above the yellow line.

Did you look in the radiator? If you have a bad enough leak it will not pull the coolant in from the overflow bottle on cool down.

 

[sdpatt]

Tighten the A/C belt by loosening the 14mm nut on the tensioner pulley about 1/2 turn, then turning the 5mm Allen screw on the top of the tensioner in the clockwise direction until the longest span of the belt (the bottom one) can only be deflected about 1/4" with a finger's worth of pressure (or until the squeak stops when the compressor engages). Now retorque the 14mm nut 25 lb-ft.

 

[Mike Kopstain]

Your coolant may be at the appropriate level in the overflow tank (Like Paul said) but if the leak is large enough, it's filling your system with air as the car cools down. You may have air in the heater core. First, find the leak, then fix it and bleed the system. Then have a beer.

 

[Jamz SHO 813]

Thank you all for replying and helping me out.
-BeatDaSHO I had the thermostat repaslced at 59k and the water pump was replaced at 70k
-Scott thanks for the help. Its so embarissing to start the car at 1 or 2 in the morning and hear me squell up the block.
-Mikey I am almost positive that the leak is from the overflow tank. I was in an accisednt in sept. The whole front was replaced with a new radiator. I checked all the hoses and they seem to be fine. But I will double check.
Thank you all. It ia greatly apperciated!

 

[Jamz SHO 813]

Ok just a couple of quick things that I noticed today...

1- The temp. gauge went all the way to "O" in NORMAL at that time the heat went on and then the needle went back down to the "A".

2-I opened the radiator cap. It wasn't hot but when i opned it there wasn't any antifreeze in sight.

3- The large hose(upper?) that goes from the radiator to the thermostat was very flimsy. I could squeeze it pretty tight.
I hope this helps. I really need to get this figuered out.
Thanks again guys.

 

[projectSHO89]

Fill the cooling system with coolant. If you can't see it in the radiator, the radiator isn't full. It what is of most immediate importance, no the overflow bottle.

See what happens after you do that.

If there is not enough coolant in the system, the upper hose will be soft. A properly filled system, warmed up and operating under normal pressure, will result in a very firm upper hose.

Watch out for additional leaking.

Steve

 

[NOTAURIUS]

are you sure its not a blend door problem. My white 90 had a similar problem. There was no heat only cold air the whole winter of 2000-2001. I had the dash pulled out and it was a 4 or 5 inch long lighter that had gone down the vents of the dash blocking the blend door from opening and therefore blowing the blend door actuator. Cost me 280 dollars to get fixed.

 

[Mike Kopstain]

Matt Delbaugh:
are you sure its not a blend door problem. My white 90 had a similar problem. There was no heat only cold air the whole winter of 2000-2001. I had the dash pulled out and it was a 4 or 5 inch long lighter that had gone down the vents of the dash blocking the blend door from opening and therefore blowing the blend door actuator. Cost me 280 dollars to get fixed.

Not with the coolant lose and being able to look down a hot radiator and not see coolant.

 

[projectSHO89]

You need two things in order to have heat in these cars:

1) Hot coolant circulating through the heater core. This is easy to check by feeling the coolant lines under the hood.

2) A heater blend door that allows the incoming (or recirculated) air to pass through the heater core on its way to the cabin via the HVAC ductwork.

A manual heater system is easy. A cable simply moves the door as a **** on the dash is rotated. Simple, cheap, reliable.

The Electronic Automatic Temperature Control is a whole 'nother mess of worms. A computer monitors the air temp in the cabin and attempts to keep it at the preset target temperature set by the driver (or the AWA, in many cases). It accomplishes this by operating a servo motor that is connected to the blend door lever. There is also a sensor assembly ( a potentiometer) connected to the actuator that provide information back to the computer as to what the current position of the actuator is. This assembly is called the blend door actuator assembly.

Any fault in the power to the assembly, the control circuitry, or the feedback circuitry can result in no heat.

The Helms service manual has a complete diagnostic procedure on how to test these components. If you don't have one, you should consider getting one.

Steve

 

[Jamz SHO 813]

Just to update, I put more coolant in the radiator the way shotimes said, removing the line from trottle body etc... The large hose(upper?) is firmer now. Where is the lower hose located? Shotimes suggests to squeeze the lower hose to allow the bubbles to pass. I squeezed the large one that goes from the top of the radiator to the thermostat. The heat still doesn't come on until it hits the "O" in NORMAL. After that it immediatly drops down past the L and slowly goes back up. Also when put the coolant in the radiator it only took about a quarter of the bottle. I havent seen any leakage. Just oil on the drivers side rear of the oil pan.
Thank you guys I am going to look for the Helms book today.

 

[projectSHO89]

Don't worry about the lower hose. FWIW, it's located at the bottom of the radiator and runs to the waterpump inlet on the front of the engine.

Keep running the engine up to temp, then allowing it to cool down fully. Keep the coolant reservoir at least half full. Top off the radiator whenever the system is cold.

It may take several heat/cool cycles to properly purge all the air from the system. In the meantime, keep a close eye on the guages. This all assumes you do have a good radiator cap and no leaks in the system.

Do a temperature check (by hand) of the two heater core lines. They should both start to warm up as the engine warms and should be of near equal temperature (any difference in temperature should be from heat extrcted from the core by the HVAC air flow). Coolant flows through them all the time. While the engine is warming up, also monitor the upper radiator hose. It should stay cool until well after the heater hoses are HOT. The thermostat should start opening at 180-195 (depending on which stat was installed) at which time the upper radiator hose should really heat up. If the upper radiator hose heats up gradually as the engine is warming up, the thermostat is not sealing adequately and may be partially stuck in the open position.

Steve

 

[Jamz SHO 813]

Do a temperature check (by hand) of the two heater core lines. They should both start to warm up as the engine warms and should be of near equal temperature (any difference in temperature should be from heat extrcted from the core by the HVAC air flow). Coolant flows through them all the time. While the engine is warming up, also monitor the upper radiator hose. It should stay cool until well after the heater hoses are HOT. The thermostat should start opening at 180-195 (depending on which stat was installed) at which time the upper radiator hose should really heat up. If the upper radiator hose heats up gradually as the engine is warming up, the thermostat is not sealing adequately and may be partially stuck in the open position.

Where are the the 2 heater core lines. I noticed early that the upper hose was sucked in and flimsy looking when I first started the car. After a few minutes of driving I checked it again it regained its shape. It was hot but i could still squeeze it together.It seems as though there was only a trickle of coolant passing through the hose.
Sorry to keep asking all these questions but I'm not too mechanic savy. I wish I was though because I am very interested in it. I don't have a job as of right now so I have to do try to do this as cost efficent as possible. Thank you all for your time. I know that you don't have to do it but ya do I'm thankful for that.

 

[projectSHO89]

Where are the the 2 heater core lines.

Almost dead center in the firewall, about 6-8 inches below the windshield cowling, are two metal connector lines with rubber hoses attached. These lines are the heater core connections. There should be (in a stock system) about 8-10" of rubber hoses that connect to metal tubes.

As far as the upper hose is concerned, It might be getting flattened due to suction from the water pump. Not normal at all. Still need to get that system completely filled.

Go work on that first (unless someone else has a better idea).

Steve

 

[Jayman]

If there is a leak it must be addressed first. What you describe after you added coolant to the rad and the fluctuating guage sounds normal. The same thing happens on my SHO's after a flush and the air is purged from the system. Once you have enough coolant in the system you will have heat as long as it stays pressurized (no leaks).
Good Luck