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SL6 Heater question
https://slantsix.org/forum/viewtopic.php?t=32985		 Page 5 of 6
Author:  Aggressive Ted [ Wed Jan 21, 2009 6:35 pm ]
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wjarjr,

Thanks for the good ideas......I am stumped too. You can't go through 2 new heater cores, hoses, caps, and thermostats in two years and not fix it. The engine was throughly cleaned during rebuild and acid cleaned too boot! Plus I acid flushed it again this year and changed anti-freeze twice. The system is clean as whistle and as close to a 50/50 mix as I can get.

It doesn't make sense. We have spent allot of money on new parts with no improvement. Even 8" of cardboard in front of the radiator doesn't seem to help. The electric fan is about the only big change in that I get some heat faster (in about 2 miles) in the mornings because the fan isn't spinning, it never comes on in the winter anyway.

Thanks again. :D

It would be great to solve the mystery why the lack of heat, sort of like your cam, it would be nice to know what grind you got in your engine............ :shrug:
Author:  bbbbbb9 [ Thu Jan 22, 2009 6:22 am ]
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Quote:
I guess its time to fix the air mixing door......
That would be my guess
Author:  Aggressive Ted [ Thu Jan 22, 2009 11:03 am ]
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I am not running a door, so it is open to the cabin air only. I blocked of the cold air inlet and cut off the end of the box.

I am recirculating cabin air so it will warm up faster in the winter, which does help allot, plus not having a fan blade constantly pulling cold air through the radiator helps too. The electric fan never comes on in the winter.
The block stays right at 190 +/- 5 degrees.

If I want cold air, in the summer I use the drivers side vent and roll the window down.
Author:  bbbbbb9 [ Thu Jan 22, 2009 11:05 am ]
Post subject: 
Quote:
I am not running a door, so it is open to the cabin air only. I blocked of the cold air inlet and cut off the end of the box.

I am recirculating cabin air so it will warm up faster in the winter, which does help allot, plus not having a fan blade constantly pulling cold air through the radiator helps too. The electric fan never comes on in the winter.
The block stays right at 190 +/- 5 degrees.

If I want cold air, in the summer I use the drivers side vent and roll the window down.



??Possible blockage in the heater core then???
Author:  Reed [ Thu Jan 22, 2009 11:46 am ]
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Ted- I have to think that your modifications to the heater box are causing your problem. I never had a problem with the stock heater box design in cold weather. Perhaps your modifications don't allow the air enough time to be heater by the core? Maybe the air passes by the core too quickly to get fully heated? I would suggest repairing or replacing the heater box and seeing if that doesn't fix the lack of heat. All other components of the system have been replaced or are in good shape, so it seems to me that the final variable is your modifications.
Author:  bbbbbb9 [ Thu Jan 22, 2009 11:55 am ]
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Super dumb question, but is it possible you have the hoses from the engine/water pump reversed? (Don't kill me).

I would think the water would still circulate anyway but who knows.
Author:  65Dodge100 [ Thu Jan 22, 2009 12:13 pm ]
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I was just thinking that heater cores don’t seem to be very reliable anymore. It seems that I replace them every couple of years once the original is gone.

I wonder if there is a difference between heater core brands. Maybe one is made with wider spaces between the fins or larger flues inside. If you still had one of your old ones maybe you could compare it to a few new ones and see if there is a difference.

Danny
Author:  Aggressive Ted [ Thu Jan 22, 2009 12:47 pm ]
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That is what I was thinking that the cores might be different. I went through 3 cores in 4 years now and they don't appear to be different, but who knows what the sizes are inside. Maybe they are smaller or constricted. Your right the original heater core worked great.

The stock heater box configuration was way colder........, at least now I can get it toasty on 40 plus degree days. It is just those 15 and 20 degree mornings it stays luke warm in the cab for quite awhile.

The inlet to the box is still the same size as the door. It isn't any bigger. Running it on high just cools the heater core faster. Leaving it on low lets it warm up faster, unless I am pulling a long grade, then the engine starts cranking out some nice heat, otherwise it is just loafing and not working very hard at all and it takes it's time warming up. It takes about 5 minutes to get luke warm air, and about a 15 minutes to get 80 degree air out of it. After about 30 minutes it isn't too bad if I drive 60 mph and make the engine work a little.

After the rebuild (per Doc's instructions for torque and mileage) it just doesn't labor very hard. In fact my average vacuum readings are much higher and the power is incredible. It is a very peppy and spunky motor. That is why I had the 8 3/4 2.76 gear posi built. The 3.23 gears were just over kill for power. It was fun, but not practical on mileage with my 120 mile round trips to work and back. The 2.76 gears net a 2 mpg average increase. The 0-30W Mobil 1 is worth another 1/2 to mpg, the distributor recurve is worth another 1/2 mpg and sometimes more on trips, the electric fan, cold ram air intake and 2 1/4" exhaust netted another 1.5 mpg. It just doesn't work to hard as a daily driver with just me in the car.
Author:  bbbbbb9 [ Thu Jan 22, 2009 12:55 pm ]
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Have you taken a temp on one of the fins?

I would think that's a place to start to see if the core is designed wrong or possibly using the wrong materials for heat transfer.

Of course after that it's about moving air past the fins.
Author:  Aggressive Ted [ Thu Jan 22, 2009 1:08 pm ]
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Yes, the core will burn the heck out of your fingers. I can shoot through the door opening and get a temp measurement. It seems to be spot on with the top of the engine head and top of the radiator tank, all are 195 degrees plus or minus 5 degrees. If I turn the heater fan on high it will cool down the motor in stop and go traffic with out the electric radiator fan coming on.

In the yard with the motor idling I can watch the the temp drop about 10 degrees on the heater core from (off to high) on the fan switch.

The new fan motor really can move the air!
Author:  65Dodge100 [ Thu Jan 22, 2009 2:23 pm ]
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Author:  65Dodge100 [ Thu Jan 22, 2009 2:45 pm ]
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Oops! This article says there should be 50F (10C) difference in the inlet and outlet.

Danny
Author:  Aggressive Ted [ Thu Jan 22, 2009 3:58 pm ]
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65Dodge100,

I am thinking it might be a water flow issue with the new heater cores. Going back to the idea that maybe the heater cores are being made differently.

The old stock unit half plugged and leaking put out more heat than the last 2 new units......

Handy units to have, we own 2.
Author:  wjajr [ Thu Jan 22, 2009 4:26 pm ]
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Ted, I purchased a new heater core from NAPA last April, installed a Detroit Muscle rebuild kit, and it heats up a drafty convertible @ 25 degrees just fine.

Someth'en ain't right with your box, flappers, and control cables.
Author:  SlantSixDan [ Thu Jan 22, 2009 4:51 pm ]
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Those heater box "improvements" are very likely a key source of your heating problems. There is no good reason to block off fresh air; recirculating cabin air just makes the windows foggy and the driver dangerously drowsy as the air very quickly gets stale.

When something doesn't work right, usually it's not because something requires re-engineering, it's because something requires repairing.

Any other non-stock "improvements" we should know about as we try to figure out why your car won't heat up...?
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