95 Aero, 3.0, with a/c. Equipped with front heater only.
Heater core, thermostat, rad flush...all DONE.

Parked and idling, I get scorching hot air coming out of the passenger floor vent. Nothing coming out of those flat tubes on the side...just a blast coming from behind the blower. It's HOT.

Switching to DEFROST I get a weak flow of warm air up top, and the floor vent continues to blow scorching hot.

Switching to VENT I get a weak flow of warm air out the dash, and the floor vent continues to blow scorching hot.

On the highway, everything cools off.

Do I have 1 or 2 problems?

First of all I think I have a mixer problem, but what's causing it? I hear hissing, but not much mechanical movement when I change the flow dial.

Second, why is it cooling off so dramatically on the highway? What can you tell me about the air intake logic on this van? Does the blower suck in outside air continuously or is there a valve that regulates fresh intake and recirculation?

 

from what i know, it sounds like a vacume line may be unhooked, especialy if you hear a hissing. there's a set of vaccume lines located behind the glove box that can get disconected if bumped. as for your air temp problem....... it's possible you could have a weak fan clutch that makes it so your coolant doesnt cool off as fast when you're just idoling your car vs. driving at highway speeds with cold air smashing into the radiator.

or your thermostat is "special" and doesn't work at idol speeds, then works over time to make up for it when you're driving.

some of the more experienced may correct me, but this is my two cents.

 

http://www.autozone.com/az/cds/en_us...rInfoPages.htm

 

There seems to be hot air rushing out from behind where the heater core pipes. I didn't replace the thick sealing foam when I put in the new heater core. I'm going to open it back up and see if I can squeeze some kind of sealing material on the side where the pipes are.
It's very cold outside and I want to take the passenger seat out so I can close the door and work in warmth.
But I noticed I require a special wrench to remove the bolt in the corner with the seat belt.
Where do I get a wrench like that? Is there something common in my tool box that will fit?

 

Regarding the parked/idling vs. driving heater air temperature difference: do you notice a difference in engine temperature on the temperature gauge?

My 95 3L Aerostar doesn't generate much heat in the winter unless I cover the grille to reduce the cold air passing through the radiator (yes, the thermostat works properly). It can get so bad that the engine won't get warm enough to allow the PCM to go into closed loop, and my gas mileage drops by about 1/3. I live in Southern Ontario & I expect it's a tad colder in SK.

Replacing the foam around the heater core should help the heater work properly. I have also seen threads in this forum that mention how pens, coins, etc. on the dash can drop down the defroster vents and block the blend door from moving properly. If you have the heater cover off again, check to make sure all doors are moving properly and are not obstructed.

Good luck with your repair.

Cheers,
Eric

 

I believe it takes a T-50 or T-56 Torx wrench socket to pull the seat belt. Most auto parts stores carry the socket and you are looking at around $10-$15 for it by itself.

 

UPDATE DEC 23:
Stuffing insulation around the core where the oem gasket used to be has stopped leakage of hot air and increased the flow to all exit vents.
At the same time I found the reason I wasn't getting passenger floor flow was because the the tube had come loose...fixed now.

SOME OBSERVATIONS:
Air volume is largest when the temp conrol is at it's coldest setting. When I had the core housing off I observed the movements inside while turning the temp ****. I see turning up the heat just closes a door and channels more air through the core; door closed=air flow through core...door open=bypass the core. And here I always thought the temp **** controlled the flow of water through the core.

Air temp is still not hot though. ( wouldn't be able to keep snow from freezing on windshield ). I have the grill half covered, and I do NOT have a winter t-stat. Would going to a hotter stat help? And what temp should I move up to?

Air flow is weak compared to my other A*, which absolutely "rumbles" the air through all the vents. I want to get inside the dash to see if the defrost vents are plugged but for the life of me I can't see how to get in there.

 

I'm pretty sure Ford "free flow ventilation" directs new air into the van instead of recycling air within the van. When on Highway, you'll be directing a bigger flow of air through the heater core (is this plenum restricted) & this cools the heater rad down quite a bit. Sounds like your fan is not pushing enough air. Have you checked the heater fan blower out ?

 

If you mean the fan blades themselves, no. What should I look for?

 

Could be that the fan blades are clogged or damaged, or the fan motor/blades is not spinning fast enough to generate sufficient air flow. You could also have leakage in the plenum or air distribution ducts. All the 4 blower speed positions work on the dash?

 

All four speads working.
I'll wait for warmer weather to look into the blower. In the mean time, I'm riding my other Aerostar. It blows air so hot you can't hold your hand in front. Go figure.

 

Since you have another Aerostar with a better blower, try swapping the blower motor/fan assemblies between the two. If I'm not mistaken, they are easily removed from under the hood.

I had a pickup years ago that had an anemic heater. The blower fan worked, but it wasn't until I replaced it due to a squealing bearing that I realized how poorly it worked. The new one moved five times as much air & the ride became toasty warm.

Cheers,
Eric

 

DISCOVERY:
I am now sure that the factory gasket around the core is a key to getting the most heat out of the core. I took it all apart this afternoon and felt around the edges of the core. There is signficant cool air escaping around the edge opposite the tubes, some around the top, and a fair amount around the bottom. Of course the edge where the tubes are is a huge air leak, but I had that plugged with insulation...which I took out tonight after thinking about the consequences of blowing fiberglass into the air.

Initially I put 1/8" foam gasket around the edges of the plenum, but that wasn't enough. I think another layer of 1/8" should fix three of the edges, and expanding foam-in-a-can should fill the void by the tubes.

While I was in there I moved the temperature **** back and forth and watched the bypass gate open and close...the gasket feels like it's sealing okay. The core is scortching hot so there is no reason I shouldn't be able to coax more heat into the cab.

BTW...I now have the passenger seat out and am comfortably able to get better reach.