I have replaced my heater core and blower. The duct that is attached the right side fresh air is blocked off with cardboard. I just cant seem to get much heat. It is just enough to keep the chill off. My engine is running 195 - 210. I have been dealing with this for 3 winters now. I am tired of it. Is this in the FE engine design or what?

 

If the engine is hot, you should have hot air coming in the cab,,,, make sure your blower is getting air to push air. Check your valve, make sure it is opening to let the HOT coolant flow into the NEW core to get circulated..... if that ain't happening... yer gonna freeze your nards! It is a very simple design,,

 

Stupid question but you put the heater hoses the right way right? I could be wrong but if they are not installed correctly I believe it blocks proper circulation.

 

I agree it is very simple design. And I dont have a valve on my heater hose. And I am freezing my nards!!! It has been getting below 0 here lately. burrrrrr.

 

And what is the right way? I didnt think that it mattered, hot water in and slightly cooler water out????

 

The flow direction through the heater core does not matter at all, it's just a flow through heat exchanger and has no directionality. My 77 F150 heating system does not have a heater valve in it either. I take it you installed a new thermostat along the way in your attempts to diagnose this heat problem correct? Many people have made the mistake of removing their engines thermostat thinking it will fix their over heating problem and if someone along the way removed yours this could also be the problem. Do you know if your temp gauge is accurate? I've heard that many of the factory gauges were not very accurate. I'm just throwing out possible things to check to cover all the bases. If everything is working correctly and your still freezing your nards off, you might have to opt for the old low tech fix....Place a piece of card board in front of your radiator to block the air flow some what. I would start with it only 1/2 blocked off and if your still cold, go to 3/4 blocked and so on. Remember to remove the card board when the outside temperature warms up or you'll over heat pretty quick. Do you have a thermostatic fan clutch (TFC) on your motor? A 'properly' functioning TFC will prevent the fan from turning until the engine gets hot and needs to be cooled. If you don't have one you should add one, it will help your engine to warm up quicker and save you a little gas as well. These thermostatic clutches do not last forever and they will fail., so even if you have one it does not mean it is functioning correctly. Let us know what you find out.

 

Oh I thought I read on here before about heater hoses going a certain way. Sorry for the bad info.

 

Check the selector switch in the dash, many of these are vacum controlled. If you can't select heat you get no heat.

 

I think it can make a difference if you want the "cool" air vent to work. If they are set up the right way, coolant flows through one heater hose to the valve and stops. That keeps hot coolant from pumping in to the core. If you have it backwards, coolant will go through the other hose, then through the core, then stop at the valve. It won't be circulating, but hot coolant will be pushing against the valve's other side through the core, and hot coolant will still be in the core. The direction won't matter for hot air, but if you want the "cool" end to work, it will matter. But usually the cool air is somewhat warm anyway. Anyway, I don't think it pertains to your problem because you are wanting hot air. My truck will smoke me out, it gets so hot. But with my Galaxie, you can barely feel it. It's possible the seals on all the duct work in the dash is going out. That's the problem on my Galaxie. You don't get warm because not much air is coming out of the vents - it's all being scattered under the dash. It's also possible you have some bad connections and your blower motor isn't getting the full 12V when you have it on high, so it won't spin as fast and circulate as much air.

 

Thanks for all the tips guys. I am going to make an attempt to elliminate these suggestion. 1. This engine is less than one year old. 2. It does have a t-stat and it is working, I can watch my 3. mechanical gauge, it will rise to 195 then drop rapidly and then slowly rise to 195 again until it is warmed up. 4.I am running an electrical fan that I can turn off on the dash. But I am going off the temp. 5. I believe that my selector is mechanical? 6. My blower seems to be working fine, it is blowing hard just not to temp. The only thing that I can think of is seals. It about has to be letting in cold air to mix some how????? Does anyone make seals for this system?

 

What seals are you talking about and we are talking about your 76 F250 correct? I'm in the process of rebuilding my fresh-air heating system in my 77 F150 and I have the whole system laying out on the table, so if you need any pictures I could easily get them right now. The only seals I think of that would make much difference here are the ones that seal the fresh vents to the kick panels on both the DS & PS. From your original post you said you had blocked off the PS with some cardboard, so you should not have a leak on that side. The DS fresh air vent should also have a seal of some kind to seal it to the kick panel. The DS vent itself probably does not make that good of seal when closed from the way it's designed, so I would make sure this one is not leaking. I would also have someone feel around for any air leaks as you are driving around on a cold/windy day and see if they can find any air leaks. The only other seals I found on the heater assembly are some thin foam seals that are used in between the parts of the heater box assembly. Like in between the heater-box and the heater box extension that leads over to the PS fresh-air vent. There are also foam seals that seal the heater core and fan to the heater box. I just thought of another seal that could make a difference, there is a thicker foam-rubber seal that seals around the fan motor to keep the the air from the engine compartment out. I noticed the new fan motor I bought to replace my old motor has a slightly smaller diameter than the original, so I will have to add some sealer to make the original gasket seal around the smaller ID motor. I really do not think it would matter much if any of the small foam seals on the heater box assembly were leaking, since the warm air that was leaking would be leaking into the cab. Have you checked to make sure that no debris are blocking the flow of air through your heater core? I found quite a bit of crap in heater box when I removed it from the truck that got in through the fresh-air vents. I'm not very familiar with the 428 engine you have, but I have heard of engine coolant circulation problems can occur if the incorrect head or intake gaskets are used or put in backwards. If this happens the coolant flow may be blocked/slowed at some point. I was thinking that if you were to install a small section of clear tubing in series w/ the heater hose going to the heater core you could see if the coolant was indeed flowing through the core or you could try and get a temperature reading at the copper heater core connecting tubes on in the engine compartment side to see how hot they are getting.

 

Run the engine to normal operating temp

Now grab a heater hose and hold onto it for 1 minute if you can... can't ? then that hose is fine

Now grab the other one for a minute.

If you have you let go of the hose because it is too hot ..you have a ducting problem.

You didn't mention having A/C or not.

Btw, these engines run at 210* F ., The T-stat value is an valve OPEN measurement not an engine operating temp

Standard heater





Heater w/AC

 

It is with out A/C. On the pic at the connector inlet, that is where I placed the cardboard, between the heater box and the duct. This did help but not alot. Isnt there a gasket of some sort on the door that controls the cool to hot control?

 

You need that duct open

That's where the air for the heater comes from.

The squirrel cage sucks that air into an past the heater core and blows it thru the plenum to the defrost vents and floor vent as shown above


Maybe a Mod will remove the AC illustration for me ?

MB - Jimmy ?

 

Isnt that just alowing colder air to pass threw the heater core? I was trying to get it only pull air from cab instead of outside air.