I have a 1970 F250 w/AC 360 engine. I am running a new 195 deg thermostat. I replaced the heater core with a NOS Ford unit. My radiator is new. My heater valve is open, but I just don't get the heat like my '65 and '66 trucks did. The heat is lukewarm at best. The hoses feel hot. My question is this- will the heater core flow coolant either direction? I don't know if it matters which heater hose mates with which pipe from the heater core. My shop manual doesn't have a clear photo detailing the routing of the hoses.

Thanks in advance- Tom

 

dont know what to tell ya. mine has that same probem. i have new radiator, heater core, water pump, hoses, thermosat, inlet is good, replaced foam inside the ducts, adjused cables, tried with and without fresh air boot, ran weaker coolant mixture, ran richer coolant mixture...... vent temps are 90F. with a poorly insulated cab its just enough to **** you off yet keep you from freezing to death. my 71 that had more problems than i could ever imagine was COOKING! at the vents. i would put the fan on low and have to shut it off it was so hot. most vehicles are at least 140F. my little ranger bakes my butt at 160F

 

Same problem here.

I'd sure be interested to know if anyone has any advice on this one.

 

This is an old old story, the problem lies with the cable operated heater water valve that splices into the inlet heater hose.

This little darlin' is notorious for getting stuck in the partially open/closed position, which restricts water flowing to the heater core.

Disconnect the cable from the valve, the lever it connects to should move freely back/forth.

C3UZ18495A .. Heater Water Valve (Motorcraft YG133) / Available from Ford.

MSRP: $38.46 // FTE sponsor PARTSGUYED.COM price: $23.08.

Fits: 1965/66 F100/1100 / 1967/72 F100/750 w/ or w/o A/C / 1963/67 Econoline / 1969/74 Econoline with factory A/C.

 

ND, that's not the problem on my truck.

I took that valve off 3-4 years ago and replaced it with a manual valve.
Both hoses get HOTTTTT!!!!, but the air coming out of the heater is only lukewarm, at best, once the outside temperature gets below 45 degrees or so. I've checked the temp of the hoses with an infrared thermometer, and they are both at 185+/- outside of the cab and inside of the cab.

I've tried reversing the hoses, with the same results.

I've also had my heater core checked, and it's clean as a brand new one inside.

 

If the problem isn't the valve numberdummy described....


Check the mode switch on the A/C control. Basiclly, make sure the mode switch isn't activating the A/C at the same time the heater is on.

Also fresh air for your heater comes from the cowl. Air enters the cowl, goes through the heater core and/or A/C then out the vents at the bottom of the truck. make sure all the seals around the heater core are good. make sure the A/C-heater control levers are adjusted properly, for proper air flow.

Next make sure the air vents are not plugged up with leaves. Remove the driver side vent on the cab right next to the parking brake pedal. stick your hand down inside and remove all the debris you find at the bottom. Leaves and crap collect at the bottom and restrict air flow from coming in from the cowl. Also remove the boot from the passenger side that connects to the A/C-heater box and clean the same way you did on the drivers side.

All these steps should increase air flowing through the system, and through the heater core. Resulting in better heat and A/C operation.

Hope this helps...

 

I've done all of these things, and I'm still only getting lukewarm air.

Of course, on the left hand side, that won't affect heater operation.

 

Yes, I cleaned out both driver and passenger side vents and cowl a while back. Just to make sure the control valve wasn't the problem I took it out and put a straight piece of copper pipe in. I blocked the radiator with cardboard and now the engine temp is up toward the higher normal range, which does help some. My AC unit is disconnected, no compressor any longer.
Thanks for all who replied. I'm just going to resign myself to the fact that this truck just won't throw heat out like my '65 and '66.

Tom

 

Tom, Speaking from 66 knowledge, the fan control switch pulls out to get more heat. From what I am reading here, it makes me wonder if that lever is not being moved.

Get under the dash and move the lever to see if it is moving on the heater box. (make sure it is moving)

My truck has very bad air leaks so I removed the fresh air inlet hose, put a piece of sheet metal over the hole on the cab side, and recycle air in the cab.

I have plenty of heat now.

Don't know if this will remedy your problem but it might be worth looking at.


guluk





John

 

1968/72 F100/350 with factory installed Integral A/C:

There are two damper doors inside the A/C/Heater plenum chamber. These doors work in unison with each other, as one is connected to the other by means of a lever.

One door is located in front of the heater core, one behind it (inner). Both are controlled by the same cable which hooks onto the rod of the inner door, then to a lever located on the A/C Heater control panel on the dash.

When you slide the lever on the control panel, the cable is supposed to open one door, close the other.

The cable could be stretched, which would not allow it to open/close the doors properly, which will cause a mixture of hot and cold air.

Or the cable may have snapped internally (it's actually two pieces, inner cable & outer housing), causing the same thing to occur.

The end of the cable is looped, it hooks over the end of the rod. A 'spring nut' fits onto the rod above the cable securing it. If the nut is missing, the cable could pop off the rod.

81-F-150-Explorer: There is no "mode" switch (19B888: A/C Temp Control Selector Valve Assy) since there are no vacuum motors that control these two damper doors.

The cars used it, but the trucks didn't until 1973.

 

No, not that switch. There is a electrical switch that turns the A/C on and off depending on where the function control lever is placed. On with the lever on A/C and off on all other functions, Floor, Defrost, off, etc... I had problems with that switch on my 1972.

Would only be a problem if the A/C works. It being on and cooling the air the heater is trying to heat up.

The heater only assymbly can be swapped in place of a broken crusty factory A/C unit pretty easily.

 

is it possible for a 40 year old engine to be so gummed up with rust, corrosion, crud, and scale on the inside of it and all its passages that the coolant just doesnt flow through the whole system fast enough? this is the only other possible reason i can think of.

for instance i would think water flowing through a heater core at 10 gallons per minute would be hotter than 1 gallon per minute because as the 30 degree air gets blown across the heater core it cools the unit down, but if you flow the water at a faster rate it doesnt have the chance to cool down and your vents are blowing 160 degrees instead of 80 degrees.