I have a fairly modded 69 F100 360 C6 and since the day i got it i havent been able to get the heater hot. It keeps me warm dont get me wrong, but i want it to where i cant hold my hand infront of the vents its so hot. (like my 71 F250 used to be) that sucker would blow 160 degrees. And this truck is only putting out 110 degrees on average, and when it gets to be freezing out, combine that with a poorly insulated cab and its okay but still just pisses you off !

I have a new radiator, new water pump, tested and functioning control valve, good 180 thermostat, and 6 month old heater core.
Also have foam insulation on my heater hoses both inside the cab and under the hood.

Inside my factory a/c underdash unit I replaced all the foam that goes in the door flappers and adjusted the cables so that it only pulls heat when i choose heat, and a/c when i choose a/c.

Not only that I tried it with and without the fresh air boot. Without the fresh air boot it raises the temperature 5-10 degrees which is not enough.
Also in my toolbox i have sitting some perfectly good other thermostats. A 195 and a 205. They help some but hurt the engine as well. From 180 degrees to 110 degrees I am somehow losing 70 degrees of heat and cant figure out how. When its warm outside it blows about 120 degrees. Cold out it blows 110. I would have to imagine this is due to poor coolant flow, but it does not appear that way as i have good flow.

 

I have a lot of air leaks in my cab, so last winter I pulled and plugged the fresh air vent. It is now recycling heated cab air and not adding cold fresh air. Made a large difference.




John

 

put the 195 thermostat in. that won't hurt your engine.

 

There were 2 heaters available for the F250's (not sure about other models, but I believe they are the same). My Crew came with the high output heater. You can also modify a later model blower to fit. I found that modification in the galleries. Jason Freeman's crewcab here https://www.ford-trucks.com/user_gal...=33756&width=0

 

i appreciate the help but the blower fan is not the issue. with the fan off and fresh air naturally pushing my vent thermometer reads 120. on low it reads 110, and on medium it reads 100. i do not ever use high speed because its like rediculous turbo speed and loud.

 

okay. but i have, and it doesnt make much of a difference. i have used a 205 and that only increased the heat slightly. i want it cooking.

 

Your heater water valve could be stuck partially open. If this occurs, it will not allow enough hot water to reach the core.

This valve is spliced into the inlet (to heater core) heater hose (on the right fender inner apron) and is cable operated.

The cable attaches to a lever on the valve, try wiggling it see if it fully opens/closes.

 

i disconnected it, held it up in the air and open and closed the valve by hand while watching the little valve inside of it fully move with no problems.

 

I had the same problem with my old '71. I put a new heater core in and it would not blow warm air. I replaced everything,then removed the heater core again and noticed that the fins were too close together and was not allowing the air to pass through. Just a thought. Good Luck
-Lance

 

First this...
Cobra Valley's Balanced Thermostats
Hmmm... not sure I go along with all that. ;)
"All that" and they forgot to mention better gas mileage with a hotter engine. LOL :)

Here's how I fixed my heater control valve problem...
http://www.panix.com/~alvinj/file12/bypass.jpg
...the original froze up right after the pickup got out of warranty. :)

Alvin in AZ

 

Remove the valve. Get a 2" piece of copper water pipe and 2 hose clamps and put the pass through in place of the valve. That way you can make sure the valve isn't the issue.




John

 

Or, you can replace the heater water valve...

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

Fits: 1961/66 F100/1100 // 1961/67 Econoline // 1966/77 Bronco // 1967/72 F100/750 // 1973/79 F600/880.

MSRP: $38.46 // FTE sponsor Y2KFORDPARTS.COM price: $23.08.

 

did you try backflushing your heater core?

 

Put something to block the air to the radiator.
Cardboard works good but you can make it out of anything.
Dad used to use cardboard in his.
Also clean out the heater core passages.
They could be gunked up.

 

no i have not. i will give that a shot. ultimately i would like to install a coolant filter. it puzzles me why no vehicles have them, cept for a few diesels.