1970 heater problems
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Fleet Owner
Joined: Dec 2000
Posts: 25,310
Likes: 5,348
From: Central PA
1970 heater problems
The heater in my 1970 F350 with a 360 does not get very hot.
The temperature control lever is free and it moves. It opens and shuts the valve on the heater hose. I used to think that maybe I had a low temp thermostat or no thermostat at all. Or the PO put a heavy duty large radiator in from a bigger truck and it was cooling too well..... But these didn't make sense. Although the temp gauge is usually just in the low side of normal. I even have cardboard in front of the radiator.....
The other day I popped the hood after the truck got up to operating temperature. The heater hose on the engine side of the heaters valve was hot to the touch. The hose was just as hot on the heater side of the valve.
So, the problem must be in the heater itself, correct? What could it be?
Thanks!
The temperature control lever is free and it moves. It opens and shuts the valve on the heater hose. I used to think that maybe I had a low temp thermostat or no thermostat at all. Or the PO put a heavy duty large radiator in from a bigger truck and it was cooling too well..... But these didn't make sense. Although the temp gauge is usually just in the low side of normal. I even have cardboard in front of the radiator.....
The other day I popped the hood after the truck got up to operating temperature. The heater hose on the engine side of the heaters valve was hot to the touch. The hose was just as hot on the heater side of the valve.
So, the problem must be in the heater itself, correct? What could it be?
Thanks!
Post Fiend
Joined: Apr 2002
Posts: 19,311
Likes: 97
From: Waterloo, Iowa
On my 64 the temp gauge is more or less useless. If it ever reads "normal" the block would have to be glowing. The heater itself though, will run your *** out. That's one thing Henry didn't **** around with I guess, they put good heaters in these trucks.
SO, if BOTH hoses are good and hot, then that means good circulation through the core. Maybe there are a lot of leaves and debris in the heater box? Or the fan motor is not doing its job...
SO, if BOTH hoses are good and hot, then that means good circulation through the core. Maybe there are a lot of leaves and debris in the heater box? Or the fan motor is not doing its job...
Thread Starter
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Fleet Owner
Joined: Dec 2000
Posts: 25,310
Likes: 5,348
From: Central PA
I didn't say both hoses and hot. The hose going to the heater is hot on both sides of the in-hose valve is hot. I will check again but the return hose was not as hot. The blower fan works good.
Leaves and debris: very possible. This truck sat for awhile before I bought it. I found leaves, acorns, small pine cones and such in both A pillars. But it doesn't make sense if the blower is blowing cool to slightly warm air both through the defrostrers and the floor that something is blocking heat does it?
Leaves and debris: very possible. This truck sat for awhile before I bought it. I found leaves, acorns, small pine cones and such in both A pillars. But it doesn't make sense if the blower is blowing cool to slightly warm air both through the defrostrers and the floor that something is blocking heat does it?
Post Fiend
Joined: Apr 2002
Posts: 19,311
Likes: 97
From: Waterloo, Iowa
Ok, I misunderstood what you wrote. Both hoses should be hot. It does sound as if the heater core is partially blocked, then.
Edit: manual sez check for closed shutoff valve, poor engine ground, loose fan belt, improperly installed or defective thermostat and plugged heater core, defective blower motor, etc.
Just as an aside, I'd recommend cleaning out the heater box, a dependable method of setting these vehicles on fire. Several people have had their trucks end up a total loss this way. The blower motor resistor (used only for lower fan speeds) gets red hot in operation and will light off anything flammable in the box. Probably doesn't happen very often but that's not much consolation.
Edit: manual sez check for closed shutoff valve, poor engine ground, loose fan belt, improperly installed or defective thermostat and plugged heater core, defective blower motor, etc.
Just as an aside, I'd recommend cleaning out the heater box, a dependable method of setting these vehicles on fire. Several people have had their trucks end up a total loss this way. The blower motor resistor (used only for lower fan speeds) gets red hot in operation and will light off anything flammable in the box. Probably doesn't happen very often but that's not much consolation.
Posting Guru
Joined: May 2001
Posts: 1,395
Likes: 4
From: Cupertino
Take both hoses off at the block. Open the valve. Take the pressure schnozzle from a garden hose and clamp it into one of the hose and turn on. Flush out any crappy doo and go from there. You may be surprised at what comes out.
New cores are widely available and not expensive. But do the above first.
New cores are widely available and not expensive. But do the above first.
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Lead Driver
Joined: Jan 2003
Posts: 9,893
Likes: 12
From: Ohio
Yup, try back flushing the core. That might get you by for a while. Not that getting the heater out of these trucks takes more then 10 minutes.....if you take your time.
I always found that the heater worked best in my trucks in the summer time? Go figure.
I always found that the heater worked best in my trucks in the summer time? Go figure.
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