I've had the problem of barely any heat, for the last couple seasons and this winter I just gotta get more heat and defrosting. Driving at 25 or less, it'll keep the windows mostly defrosted, but anything faster, I'm in a world of hurt for vision. Also, if I switch to floor..or any other setting... I'm still going to freeze my poor old tail off.
So.. at my delicate age and with my medications, I can't tolerate high heat nor excessive cold. I sure can't afford another truck, living on Social Security, so any advice or help diagnosing this issue, would sure be a help.

Last summer I tried an engine flush, thinking maybe the heater core was plugged, but there seems to be hot water flowing in and out, through the hoses. Not totally positive about the "out" part though. They're so close together that I can't really tell. One question about the hoses. In one hose, there seems to be something hard in the line. No idea what it even is and wonder if there's something that'll plug up and require hose replacement. This hard item is in the middle of the hose and I can't even figure out how in the world they'd put it there, to begin with. So, if anyone knows what it might be, that'd help too... if for nothing else other than satisfying my curiosity.

A friend might be able to help me pay a dealer to do the work, but it'd sure be nice to tell the service dept what I believe the problem to be, so that they don't try replacing the whole vacuum system, door motors (?) or whatever. I do notice, down by the floor, there's a vacuum unit. Could that be what's bad? I don't hear a vacuum leak, with the exception of after turning off A/C, I hear a hiss, for just a few seconds.

Ok...'nuff babbling on. I'm so frustrated, because my truck has been such a great unit all these years. Oh.. the mileage is right around 165,000.

Thanks in advance, for any ideas or suggestions. Have email notifications set, so I'll respond back as quickly as possible.

- to the bone!

 

Your first test is to feel the two heater hoses with the engine fully warmed up and the heat on high. Both hoses should be hot to the touch. If they're not then it's a restricted heater core or otherwise some sort of coolant flow restriction. If they're both hot then it could be an issue with your blend door that mixes the hot and cold air is not going over far enough. This leaves you getting mixed air instead of only hot air.

 

Thanks for your input. I will do some checking tomorrow, on the heater hoses. Do you have any idea what the hard lump in one of the hoses might be?
Driving today, I was getting warm air through the floor, but was distracted by a new engine noise, that occurs under semi-hard acceleration. Kind of a rattling noise, not a rod knock. Sounds possibly like a timing issue.

Man... when things start going wrong, seems like they all attack at once. I'm thinking the timing belt may have some issues. I read something about that in a post in another forum.

Anyway... is there an easy way to check the door to see if there's something blocking it? I AM notorious for tossing junk on the dash and it's quite possible a pen or something may have dropped down the defrost vents.

I guess I'll have to break out the Haynes manual and see what kind of destructions it gives for accessing that area. Sure hope I don't have to take the whole dash out.

Anyway... thanks again, for your response. I'll try to get some checking done tomorrow.

 

There is a restrictor in the input hose to the heater core. I believe the restrictor appeared with the modular engines appearance in 1990's cars. Maybe due to the different water pump/routing setup on modular engines as compared to Ford small blocks? I don't know.

Anyway, if no one has messed with it before and mixed the hose connections to the core up, the hose with the restrictor is the heater core input hose, so the other hose is the heater core's output, for your temperature comparison test, which really needs to be done.

 

Checked both hoses and they're both hot, with heater on high and after taking a short drive. So, it appears that the core isn't plugged.

Seeing as it's been a while, I don't remember how hot the air is, coming out the floor, but with warm weather and temp up to where it should be, there's pretty warm air coming out the floor. When the truck was new, it'd run us out, even in dead of winter. So.. this blend door thing is sounding more logical. I spun the /cool to hot **** both ways and got cool air and then warm air, so the blend door moves a certain amount anyway.

Well ... still at square one, so I guess we'll wait nd see how the temps go, as the weather gets colder.

 

On some models the hinges beak and the blend door moves partially but not fully side to side.

 

I'll have to break out the shop manual and see if the blend door is easy to access, without removing the dash. I really don't want to remove the dash! Thanks for your response.