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Heater Replacement/upgrade - Electric Options?

Go to solution Solved by tek-nic,

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Hey everybody - I have a wild hare of an idea, and want to post it up to share. 

I own and daily drive a 1970 2002. It's a base model, with absolutely zero optional equipment. 


When I got the car, the heater fan was not working, and the heater core connection was leaking. 


I have since bypassed the heater core for the time being, and have been driving around covered in blankets, coats, and hats all winter long. It has been a very cold winter... I can tell you that for sure. 


The car has done great in the cold, never stranded me once. I, however, am not as tough as I thought I was, and have decided that I need heat. 


This got me thinking about the whole situation, and the fact that I don't like the way an original 2002's heater works, especially the way the temperature is controlled. 


So I want something different. Something reliable, something that can give me heat when I need it, without a lot of trouble or plumbing. 


Website link:


Here's my current idea... 


It is 12 volts, with a 40 amp draw, and puts out over 2300 btu


I know that I can physically make it fit, and I am pretty sure that the 2300btu will be plenty, but I am concerned about the draw. I do have a nice Optima red top battery, and the car came with what appears to be a fairly new bosch alternator. I dont have a stereo, or anything like that to draw any juice. 


Does anyone have experience with these kind of quartz heaters, or putting a load like this on a 2002's electrical system? Obviously I can wire directly to the battery, but I am still looking for any advice or experience relating to the subject. 


Any help, or alternative suggestions is greatly appreciate. 

I love this thing!

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A 1970 2002 has a 35 amp alternator, so your electric heater will draw more current than the alt can produce.  You can fit an 85 or 105 amp alternator from an E21 or E30 to give you enough juice, but repairing your heater isn't that terrible a job, esp if your car doesn't have A/C.  Since you've already bypassed the heater the core is presumably dry by now, so removing it won't be messy.  


On a '70 the two control panels (air selection and temperature) come out with the heater, so the only thing you have left to disconnect are the wires that go to the speed resistor on the heater body up under the dash.  Then remove the console and four nuts, and out comes the heater, complete with temp control valve.  Have a radiator shop repair and test the core, check the FAQ for how to revive a heater fan (or replace it with a compatible fan motor that fits), reassemble and you're back in business.




'69 Nevada sunroof-Wolfgang-bought new
'73 Sahara sunroof-Ludwig-since '78
'91 Brillantrot 318is sunroof-Georg Friederich 
Fiat Topolini (Benito & Luigi), Renault 4CVs (Anatole, Lucky Pierre, Brigette) & Kermit, the Bugeye Sprite

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Thanks Mike! That is exactly the information I was looking for.

If I can figure it out, I think I would rather have an electric heater... I just need to check which alternator I have, and then look into getting something that can handle the load. 


I've done heater systems in the past, and I am sure I could figure this one out... but I still don't really like the actual design of it. 

But, I am still a bit of a noob with 2002's, so maybe my mind will change. Am I correct in this understanding... the temperature selection slider thingy actually controls a valve which changes how much coolant is flowing through the heater core. Is this correct, or am I smoking the wrong pipe? 


Thanks again...

I love this thing!

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The temp slider on an early "70 simultaneously controls a valve that regulates flow through the heaer core and a flap that adjusts the mix of heated vs outside air through the heater box. The two sliders on the left of the dash control the flaps that regulate the exit air flow from the box with the top level adjusting the flap to the defrost outflow and the lower the flaps to the footwell outflow. Finally, there is the fan speed control on the dash binnacle. When the heater box is restored to good condition (working fan, restored flap foam, etc), it works quite well).

Rob S
'69 2002; '04 330i ZHP; 2018 X1; 2014 535i; 2017 340i

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From personal experience, after driving an 02 in Kodiak, Alaska for 10 years I can certify that a properly functioning stock 2002 heater is MORE than adequate to keep you nice and toasty.  Just follow any of the heaterbox refurb threads here, you'll have plenty of heat.


Life's a garden baby, dig it.

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An internal combustion engine is never more than 50% efficient.  In an ideal world, you might get

40% of the energy in the gasoline transferred to power.


In the real world, you don't see 20%.


Guess what the rest goes out as?






So WHY on God's green earth would you spend ANY of your (not quite) 20% motive force on heating the



Yes, fix the stock heater.


Yes, replace it with a heater that's designed to last more than 5 years.


Yes, add an extra core in the back seat for the kid.


But you're already exhausting most of your fuel energy as heat.


So why not put it to use???


(rant over)


(no, I don't think an electric heater in a gas powered car is all that good an idea)



"I learn best through painful, expensive experience, so I feel like I've gotten my money's worth." MattL

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In a pinch the cigar lighter will keep your fingers warm, (ask me how I know)

Edited by dbmw2002

Happy Trails to u~ Dave Miller
76 Golf~Rhiannon~BM Mascot~*~97 328is~Silver Ghost~*~68 1600~Wisperin Beast~*~70-02~Bumble Beast~*~76 02~Beast~

Keep smilin all the way

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  • Solution

Thanks for all of the replies. As I said before I may change my mind,

Yes, I know that a motor isn't 100% efficient, and the waste is heat. I am very aware of this. 


The comments about the abilities of this stock design have been encouraging for me - as that was really my biggest concern. 

I think I am going to install a smaller electric unit for the moment, and go ahead and gut the entire heating system and restore it over a couple weeks. I daily drive the car, so sometimes I have to crack eggs differently. 


Thanks again :) I have a build thread around here somewhere... I will try to remember to update it with the progress I make on the heater system. 


Regards - 


I love this thing!

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