Joe Flanagan Posted December 14, 2013 Report Share Posted December 14, 2013 I just installed the heater in my 49 Plymouth and it seems to me it doesn't produce much heat. The system is full of coolant, there are no leaks, and the core has been tested and cleaned. The fan motor works nicely. It's moving enough air, but the temperature of the air is lukewarm at best. Hot water is definitely getting into the core. I have been testing it with the engine at idle, so maybe that's not an accurate test. But I let the engine run for a long time and left the heat on and the temperature of the air coming out of the vents didn't change. For what it's worth, my heater is the 550 model, which has the blower and heater core under the hood and a long cardboard duct that passes through the firewall. Could it be that it's just a lousy design and by the time the air makes it into the cabin it's lost most of its heat? Am I mistaken to do this test at idle? The manual heater vent on the head is wide open, by the way. Quote Link to comment Share on other sites More sharing options...
desoto1939 Posted December 14, 2013 Report Share Posted December 14, 2013 Joe: Rich Hartung here. When you have the engine running and the heater is turned on can you feel any heat on the two hoses that feed the heater. On my 39 Desoto which is know is a different heater. The connection at the back of the head goes into the pipe that is near the drivers sign and the return is the pipe that is near the right front fender. May be you have the hoses connected to the wrong connection on the heater. Just a possibility. Rich Quote Link to comment Share on other sites More sharing options...
Young Ed Posted December 14, 2013 Report Share Posted December 14, 2013 Do you have a 160° thermostat? If you are comparing the heat to a modern car with a 195 or even higher thermostat that's where you'll notice a difference. Also remember your heater core is out on the fender with an air duct bringing the warm air in so there is a little more chance for a cool down before the air is inside. When you are actually driving on the road it will be somewhat better as the movement of the car gets you some additional airflow. Quote Link to comment Share on other sites More sharing options...
Joe Flanagan Posted December 14, 2013 Author Report Share Posted December 14, 2013 Thank you, guys. Rich, I'm pretty sure I have the hoses connected the right way but I'll double check. Ed, I believe my thermostat is a 160 and I agree, it looks like the air has to travel quite a long way before it gets into the cabin, so maybe there's heat loss there. It's cold here today and when I opened the door to the car, I have to admit I was pleasantly surprised at the temp difference inside, so it is doing some heating. I'm comparing it to what I'm used to in a modern car, so maybe I just need to adjust my expectations. Quote Link to comment Share on other sites More sharing options...
Joe Flanagan Posted December 14, 2013 Author Report Share Posted December 14, 2013 Just checked the hose arrangement and I have it as Rich describes. All hoses are hot when the engine is running. Quote Link to comment Share on other sites More sharing options...
1941Rick Posted December 14, 2013 Report Share Posted December 14, 2013 Do not forget, you probably have a 0 pressure cooling system. There is less flow to the heater. Not helped any by a 160 thermostat. Solution: drive in warm weather..... Quote Link to comment Share on other sites More sharing options...
Niel Hoback Posted December 14, 2013 Report Share Posted December 14, 2013 Joe, if you have a temp control knob, make sure it is pulling the valve all the way open and not restricting the flow of water. Pressure in the cooling system will not affect the flow. The direction of the flow thru the core doesn't matter either on heaters without a temp control valve. 1 Quote Link to comment Share on other sites More sharing options...
TodFitch Posted December 14, 2013 Report Share Posted December 14, 2013 . . . I'm comparing it to what I'm used to in a modern car, so maybe I just need to adjust my expectations. Modern cars have thermostats that opens at a lot higher temperature than yours. The one in our 2001 is spec'd to start opening at 199°F. When it is cold out and there is no load on the engine you're likely to find the coolant temperature isn't even to the thermostat spec. For example, I've got a 160°F in my '33 but most of the time in "winter" (term used loosely because of my location) the temperature on my gauge is 140° to 150° (I calibrated the gauge so I'm pretty sure of those numbers). Basically if the cooling system is in good shape and the ambient temperature is low, the thermostat only barely cracks open. So the coolant into your heater may be 50° or 60°F lower on your truck than it is in your new(er) vehicles. That makes a big difference. If you throw in a 180°F thermostat you heater will be more capable. Quote Link to comment Share on other sites More sharing options...
greg g Posted December 14, 2013 Report Share Posted December 14, 2013 You have a 160 degree stat but what is the actual coolant temp? Are there any breaks in the ducting where the movement of air through the duct could pull in outside air on the car side of the heater core? Is the entry of air into the system restricted in any way? I remember my dad 49 and 54 Dodges with similar set ups, and those heaters were marginal performers. He would block half the radiator with a piece of old carpet to raise coolant temp, to make the heater more effective. If Niel's suggestion regarding the valve being not fully open, you might want to consider blocking part of the radiator. Typically a heater core will pull about 30 % of the cooling load in any given system. So by opening the valve to the other heat exchanger you are adding 1/3 more btu transfer than just the radiator. Quote Link to comment Share on other sites More sharing options...
Don Coatney Posted December 14, 2013 Report Share Posted December 14, 2013 Do not forget, you probably have a 0 pressure cooling system. There is less flow to the heater. How does pressure make a difference in flow? Quote Link to comment Share on other sites More sharing options...
Joe Flanagan Posted December 14, 2013 Author Report Share Posted December 14, 2013 (edited) OK, thanks for all that. I got a dash-controlled on/off valve some time ago (new) and as I recall, it does open all the way but I'll have to go back and check that. Regarding air flow/obstruction, it isn't the greatest, but quite a bit of air does come out of the duct on the passenger side. The one on the drivers side you can barely feel the air coming out. The old cardboard duct behind the dash was collapsed and deteriorating and I rebuilt it using fiberglass and mesh. There are places where it's still partially collapsed and I'm sure the air is obstructed. But as I said, there is good air flow from the passenger side, it's just that the air itself isn't very warm. I haven't had it out on the road and won't for another few months, so I think I'll call it done and revisit once she's roadworthy. Edited December 14, 2013 by Joe Flanagan Quote Link to comment Share on other sites More sharing options...
Don Coatney Posted December 14, 2013 Report Share Posted December 14, 2013 Joe: Rich Hartung here. When you have the engine running and the heater is turned on can you feel any heat on the two hoses that feed the heater. On my 39 Desoto which is know is a different heater. The connection at the back of the head goes into the pipe that is near the drivers sign and the return is the pipe that is near the right front fender. May be you have the hoses connected to the wrong connection on the heater. Just a possibility. Rich Why would the direcction of flow make a difference? You are correct in saying the hottest water comes from the back of the head and returns to the suction side of the water pump but why would it matter what direction the water flows? I do not understand? Quote Link to comment Share on other sites More sharing options...
JerseyHarold Posted December 15, 2013 Report Share Posted December 15, 2013 As Greg said, these systems were not known for huge heat output. In my father's original '52 Cambridge the heat was marginal at best. My parents and I were amazed at how much more heat was produced by the heater in our next car ( a new '65 Coronet). Quote Link to comment Share on other sites More sharing options...
Joe Flanagan Posted December 15, 2013 Author Report Share Posted December 15, 2013 The funny thing about it is I believe they call this model heater the "Comfort Master." Cold comfort, if you ask me. Quote Link to comment Share on other sites More sharing options...
DJ194950 Posted December 15, 2013 Report Share Posted December 15, 2013 Joe checked my 550 heater on the 50 4 dr. Ply. Within a minute or two had 80 degree temps at the vents, within 5 min. had 102 d. at the pass. side cabin outlet, 98 d. on the driver side I know it's 50 d. here now and you're nowwhere near that but with a termostat you should also get there. Mines is 180d. not a 160. Have you adjusted the vent throttle for the frest air on the underhood box per the pic.? Blocks heated air from passing to the fiber tube to the interior. I used a repalcement type of the water control valve as you did but not the same one, mine was was flow directional, where correct hose was supposed to go to a particular connection. Does it make a diff.? Don't know but it came out just the same as the pic attached, You Need a heater where you are! Best, Doug 550 mopar heater install.bmp Quote Link to comment Share on other sites More sharing options...
Joe Flanagan Posted December 15, 2013 Author Report Share Posted December 15, 2013 Hi Doug, You know, that's one thing I haven't done, check the vent throttle. I assume this refers to the baffles inside the box under the hood. Maybe I should switch to a 180 degree thermostat. We had heavy sleet here today starting about 2PM and continuing the rest of the day. Tomorrow is supposed to be better. I'll probably be able to get out there and check some of these things out. Quote Link to comment Share on other sites More sharing options...
DJ194950 Posted December 15, 2013 Report Share Posted December 15, 2013 Yes Joe, I was referring to the interal flap that is controlled by the arm on top of the heater box. The diff. between Hi/low blower speeds only seems to make a small diff. with airflow inside the vents. Both of my heater blower motors- heater/defroster are changed to 12v. and new as are the heater core all ductwork ,new cardboard tube underhood and rebuilt from steel/fiberglass ductwork copy inside. Will cook me out in this (warm) climate even without the blowers on after getting it all warmed up! Hope yours will do the same! Best, Doug Quote Link to comment Share on other sites More sharing options...
Joe Flanagan Posted December 15, 2013 Author Report Share Posted December 15, 2013 Well, Doug, that was the solution. I changed the position of the flap inside the duct and now I have nice warm air coming out of the vents. In fact, I could imagine it getting uncomfortably warm once the car got out on the road. Yesterday I was concentrating on everything but that flap and so it was kind of a "DUH!" moment. I don't have the cable hooked up to the control yet, so I'll do that this morning. Everything looks good. Quote Link to comment Share on other sites More sharing options...
RobertKB Posted December 15, 2013 Report Share Posted December 15, 2013 Glad you found a solution. That heater flap is something a lot of people forget about. The heater in my '53 Plymouth works the same basically and will roast you outta the car, even with a 160 thermostat. I have driven the car is some pretty cold weather and always been warm. Don't mind driving in cold but not on the icy roads we have or if there is a lot of sand and small gravel as we have on the roads now. Ah, for spring. Quote Link to comment Share on other sites More sharing options...
DJ194950 Posted December 15, 2013 Report Share Posted December 15, 2013 (edited) Joe glad you found an easy fix, not enough of those to go around. Best, Doug Edited December 15, 2013 by DJ194950 Quote Link to comment Share on other sites More sharing options...
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