no heat. no AC. possible causes?

[fiveoho]

well, this actually isnt on my mustang but my 98 explorer. little chilly this morning on my way to work and decided to turn on the heat. blows air , just not hot - or even warm. temp gauge looks normal. drove it 20 min without any change. tried vent, floor etc. nothing. just air.

about 2 months ago i had the local dealership flush the coolant system. the overflow jug was nasty black so i figured it would be a good idea as preventitive maintenance. never tried the heat after they done this until today. not pointing fingers but i am wondering if during the flush, the heater core got plugged with any trash that was in the system ( i -really- hope not ). the thermostat was changed probably about a year ago and i would assume that would not be the cause as it should effect the actual temp of the motor, which i would notice on the gauge? im hoping it may be the heater control valve. what are some other things it could be?

this is probably a separate issue but prior to this ( about 2 weeks ago ), my AC stopped blowing cold. would blow fine, just not cold. the compressor kicks on and off.....alot. i know i have a leak somewhere in the system but instead of possibly spending big bucks to find it, i just ad about 2 cans of refrigerant during the course of the summer and that gets me by. well the last can only lasted about two weeks and the air turned cool rather than cold. recently added a can of refrigerant that has dye. that can lasted a few days and kept the compressor from kicking on and off so much. air got cold again. during the time it was in there, the drier turned a color of green. a closer inspection, it appears the drier has deep rusty spots on it. i assume this may be where my leak is. the best to descibe the green is that it almost looks like a moss is growing on it. back to being 'cool' air.

im thinking i have two separate problems here. i know the blend doors could be linked to both of these but i have a feeling that isnt it.

the heat im more concerned with right now as cold weather is approaching but id really like to figure out the AC problem as well.

fwiw, its a EB explorer with the digital heat & air controls.

thanks guys.

 

[fiveoho]

im just hoping when i check both heater hoses coming from the firewalll, they are both hot with the heat on

 

[fiveoho]

with the truck up to operating temp and the thermostat set on 90, both heater hoses in the firewall are very hot. i assume this determines that the heater core is working properly.

 

[wmburns]

FWIIW, the design of the 4.6/5.4 has the water flowing through the heater core all of the time. In fact, the design of the water pump depends on this flow. This is why if your heater core fails and you wish to do without, the heater hoses have to be looped instead of plugged.

So, feeling to see if the heater hoses are hot and have flow is not really a complete test as there are no water valves in the loop. Water flows all of the time.

If the heater core were blocked with trash, the blockage would have to be almost complete. In an otherwise working system some heat would be felt.

If asked to guess, my vote is the heater blending door is stuck in the closed position. No air over heater coil = no heat.

Just to be on the safe side, I would do a quick check of the fuses.

IMO, your AC problem is a garden varity Freon leak. The green dye is hard to ignore.

Disclaimer. This is not a Mustang. I don't have the same level of service manuals and such. Use this at your own risk.

 

[fiveoho]

this is actually on a 4.0 sohc motor. so what you are saying is that even if the heat is off, the two hoses in and out of the firewall will still be hot?

im thinking there is a heater control valve somewhere in the mix.


thank u for your input