Heater Problems
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New User
Joined: Dec 2000
Posts: 4
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Heater Problems
Ok so I'm from Georgia and it's not (usually) cold down here. My '77 F100 w/ 300 I6 is blowing cool air when running down the road and it's 30 degrees out. My temp gauge ain't working (just found where the temp sensor was at today). I was looking for some ideas before I replaced the thermostat.
Senior User
Joined: Mar 2000
Posts: 113
Likes: 0
Heater Problems
I would check the level of your coolant in the radiator, and then if it,s ok I would check my temp slide control and make sure that it is actually moving the valve that is located under the dash on the passengers side of the cab. Move your temp control to warm and watch the cable where it attaches on the other end. Make sure it is moving the valve. Also if you have had your heater hoses off or replaced, make sure that the hot hose is connected to the top fitting under the hood. Hope this helps. Other than that you may need to back flush your heater core.
BJ 1977 F150 4x4 Flairside "Bubba Grape"
400 C/6 B&M LT Mega Shifter
6" suspension lift 35x12.5x15 BFG,s
"Have you driven under a Ford Lately?"
BJ 1977 F150 4x4 Flairside "Bubba Grape"
400 C/6 B&M LT Mega Shifter
6" suspension lift 35x12.5x15 BFG,s
"Have you driven under a Ford Lately?"
Cargo Master
Joined: Jul 2000
Posts: 2,281
Likes: 18
From: Northern California
Heater Problems
Sounds like two problems:
1. you have to fix the temp gauge to find out just how hot the engine is getting.
2. find out is the hoses to the heater are setup properly. The hoses should have hot water as soon as the engine warms and even before the them stat opens. Run the engine from cold for about 2 min. Grab the hoses from the engine to the heater, they should be warm.
Check to see if someone removed the them stat or re-routed the hoses.
Check to see that the heater control valve works and allows water flow, turn off the engine, remove the heater hose, turn heater temp to hot, blow thru the hose, it should allow flow thru the heater core ( the control valve could be stuck, broken)
1. you have to fix the temp gauge to find out just how hot the engine is getting.
2. find out is the hoses to the heater are setup properly. The hoses should have hot water as soon as the engine warms and even before the them stat opens. Run the engine from cold for about 2 min. Grab the hoses from the engine to the heater, they should be warm.
Check to see if someone removed the them stat or re-routed the hoses.
Check to see that the heater control valve works and allows water flow, turn off the engine, remove the heater hose, turn heater temp to hot, blow thru the hose, it should allow flow thru the heater core ( the control valve could be stuck, broken)
Fleet Owner
Joined: Jun 1999
Posts: 24,552
Likes: 74
From: Creedmoor, North Carolina
Heater Problems
Chris, until you get it fixed, try placing a piece of cardboard in front of your radiator to block air flow. That should help in the short term.
John
jowilker
66 F100s
In the still cool hours of the night,
you can hear chevys rusting away.
John
jowilker
66 F100s
In the still cool hours of the night,
you can hear chevys rusting away.
New User
Joined: Sep 2000
Posts: 8
Likes: 0
From: Long Prairie
Heater Problems
[font size="1" color="#FF0000"]LAST EDITED ON 01-Jan-01 AT 05:47 PM (EST)[/font][p]Hey John;
Take it from a life long Minnesotan. When you use cardboard it needs to go in front of the grille. If you place it directly on the radiator it can do some nasty things to fans, waterpumps and radiators!
Jerry D.
Slick 60's truck club
Midwest Chapter
Take it from a life long Minnesotan. When you use cardboard it needs to go in front of the grille. If you place it directly on the radiator it can do some nasty things to fans, waterpumps and radiators!
Jerry D.
Slick 60's truck club
Midwest Chapter
Fleet Owner
Joined: Jun 1999
Posts: 24,552
Likes: 74
From: Creedmoor, North Carolina
Heater Problems
Jerry, I'll have to take your word for it, sounds like you have some personal experence. I usually start slipping it in from the side until I get heat. Everything in my truck is new now so I don't worry.
John
jowilker
66 F100s
In the still cool hours of the night,
you can hear chevys rusting away.
John
jowilker
66 F100s
In the still cool hours of the night,
you can hear chevys rusting away.
Lead Driver
Joined: Nov 2000
Posts: 6,624
Likes: 342
From: Albuquerque
Heater Problems
Can you guy's tell us more about the hose routing and water valve placement? My 77 used to run you out of the cab but now the heater air doesn't get real warm untill the thermostat opens. Maybe my hoses are backwards? One hose comes out of the top of the water pump, goes through the valve into the heater core and returns to the engine block fitting next to the thermo hosing. Itsa 400c.i.
1977 Ford F-100
280,000 miles
Stock on the outside
modified/rebuilt everything
1977 Ford F-100
280,000 miles
Stock on the outside
modified/rebuilt everything
Trending Topics
Fleet Owner
Joined: Jun 1999
Posts: 24,552
Likes: 74
From: Creedmoor, North Carolina
Heater Problems
Harold, it's not at all unusual for these old Fords just to not get hot in the cab. Flushing the system will help. If you haven't changed out anything the hoses should be ok. As far as I know the heater is free flowing and I can't see why it would matter which way the hoses were routed.
John
jowilker
66 F100s
In the still cool hours of the night,
you can hear chevys rusting away.
John
jowilker
66 F100s
In the still cool hours of the night,
you can hear chevys rusting away.
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Senior User
Joined: Jan 2001
Posts: 140
Likes: 0
Heater Problems
you also might have a heater hose that is colapseing inside
have a friend start and warm up your truck then have them rev up the motor it dosent take much squese your heater hoses inch buy inch and check for soft spots if the hose is seperating inside it will feel real soft and squishy
also take off your raditor cap after you first start your truck when it is cold and see if it looks like antifreez is moving or ciculating through the raditor
good luck mike
have a friend start and warm up your truck then have them rev up the motor it dosent take much squese your heater hoses inch buy inch and check for soft spots if the hose is seperating inside it will feel real soft and squishy
also take off your raditor cap after you first start your truck when it is cold and see if it looks like antifreez is moving or ciculating through the raditor
good luck mike
Junior User
Joined: Sep 2000
Posts: 99
Likes: 1
Heater Problems
Does it blow hot (or even warm) if it's just sitting, ideling for awile? Or after it's been sitting for 10 minutes or so after it's been running down the road? If so, your thermostat isn't working properly. replace it with a new one (195 degrees works best), That should cure your problem.
If it never blows warm or hot, you could have a bad heater control valve (conected to one of the heater hoses) It should have a small vacume line conected to it. If you think that that's your problem, try installing a piece of heater hose so that it runs straight from the engine to the heater core (no valve) and see if it gets warm. If so, the valve needs replaced.
Also, if your truck has A/C, make sure that the compressor isn't running when the heater is on (open the hood and look!) I've had the A/C- heater switch go bad so that the A/C runs in any position other than off! ..... Good luck!
P.S. Just as a CRUEL sidenote! It was 78 degrees out here where I live today! (sorry! I just had to tell you!)
If it never blows warm or hot, you could have a bad heater control valve (conected to one of the heater hoses) It should have a small vacume line conected to it. If you think that that's your problem, try installing a piece of heater hose so that it runs straight from the engine to the heater core (no valve) and see if it gets warm. If so, the valve needs replaced.
Also, if your truck has A/C, make sure that the compressor isn't running when the heater is on (open the hood and look!) I've had the A/C- heater switch go bad so that the A/C runs in any position other than off! ..... Good luck!
P.S. Just as a CRUEL sidenote! It was 78 degrees out here where I live today! (sorry! I just had to tell you!)
Fleet Owner
Joined: Jun 1999
Posts: 24,552
Likes: 74
From: Creedmoor, North Carolina
Heater Problems
If you want to remove the valve for testing you can put a piece of 1/2" copper tubing in, clamp it, and your line will be open and available.
Big Al, if you bees from Cal. your state will be shaking, burning or sliding soon, so take it easy on our cold ices, OK?
John
jowilker
66 F100s
In the still cool hours of the night,
you can hear chevys rusting away.
Big Al, if you bees from Cal. your state will be shaking, burning or sliding soon, so take it easy on our cold ices, OK?
John
jowilker
66 F100s
In the still cool hours of the night,
you can hear chevys rusting away.
Lead Driver
Joined: Nov 2000
Posts: 6,624
Likes: 342
From: Albuquerque
Heater Problems
Claw2, hope you got yours fixed. Sorry for horning in on your thread. As for mine most everything is new/rebuilt at this time. Heater eventually gets hot. I think I'll try bypassing the valve. It could be in backwards or clogged up. I took the vavuum hose off it to make sure it was open(vacuum pulls it closed). I'm looking for a new vacuum switch for the dash. It seemed to be leaking/pulling the valve closed just a little when it shouldn't. Hey, it's old! Seems like the more I repair the more I find wrong. At least it's a Ford.
1977 Ford F-100
280,000 miles
Stock on the outside
modified/rebuilt everything
1977 Ford F-100
280,000 miles
Stock on the outside
modified/rebuilt everything
Logistics Pro
Joined: Feb 2000
Posts: 3,565
Likes: 9
From: Sun River St. George
Heater Problems
Flush the heater core, change the hoses and install a manual shutoff in the hose. 10 months out of a year you don't want any heat in the cab, ahhh yes...I love the South! In winter I open the valve. If it gets to warm in the cab I open the window. Did I mention how much I enjoy living in the South?
William in Atlanta
William in Atlanta