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Posted by: Van B Nov 3 2021, 07:05 PM

I got no movement when I put 12v to the wires and trying to spin the fan by hand is a challenge so, I think it’s dead.

Now what to do? I see pelican parts has a Bosch motor only, a Porsche fan+motor assembly, and a URO fan+assembly.

What have you folks done for your heater blower rebuild and how has it worked out?

I’ll say up front, I’m biased toward the Bosch motor for two reasons: 1.) It’s a Bosch 2.) I’m not excited about a plastic fan in the engine bay.

Thanks,
Van

Posted by: bdstone914 Nov 3 2021, 07:13 PM

What year is the car? I have several good used ones for $50 plus shipping.
Not all have a plastic fan wheel.

Posted by: Van B Nov 3 2021, 07:45 PM

It’s a 1974 1.8L. Porsche and URO are plastic fans. That’s why I’m leaning toward the Bosch motor only option.

Blower is part number 914572011.10

Posted by: Van B Nov 4 2021, 12:41 PM

c'mon guys. There's no way I'm the only one who's ever sought to rebuild the heater blower... although the limited info I found searching would seem to disagree with my hypothesis!

Posted by: BeatNavy Nov 4 2021, 01:11 PM

When I first got my 914 I wanted a strong working blower motor. I figured it's one of those things I just need to make work. So I picked up a couple on the side at Hershey and other places. But then I found even the most serviceable one I had didn't really put out much air. I found that down-shifting and regular driving resulted in a lot more heat on the windows and the cabin. So I ditched the blower which makes things slightly roomier in the engine bay.

YMMV

Posted by: Van B Nov 4 2021, 01:42 PM

So, you're just open vent tube in the engine bay?

Not sure that solution will get much traction with the wife... Taking her out in the cars often is a key component to my funding strategy for these toys. As long as she's being entertained, I don't get questions about my expenditures lol!

Posted by: mepstein Nov 4 2021, 02:02 PM

I ran without a blower motor on my 1.7 through a couple winters and I was warm and toasty. The heat exchangers put out a lot of heat and the heat will make it into the cabin without the blower. The engine fan will push it along. I used to crack the windows while moving and it would pull even more heat from the heat exchangers. I do the same in my 914-6. No blower, just backdated heat.

Posted by: Van B Nov 4 2021, 02:09 PM

well that hasn't really worked on my car so far. I have to put my hand right on the vent to feel the heat. And that's only when I move the top slider mid-way. if I move it further over to turn on the frunk blower, it's totally cold outside air.

I appreciate the feedback and all, but I'm trying to fix the heater blower, not throw it away.

Posted by: BeatNavy Nov 4 2021, 02:46 PM

The top slider is only fresh air. All the way to the left is closed, all the way to the right is wide open and frunk blower on high.

The amount of heat allowed into the cabin is control by the lever between the seats. Do you have that open all the way? If so, and you're still not getting a blast of hot air on downshifts, then there is something else going on. That blower you are so eager to have working is controlled by that lever. All the way up and the relay grounds, turning the blower on. In any other position the heater blower is idle.

Posted by: mepstein Nov 4 2021, 02:58 PM

If the air from the longs isn't HOT, something is amiss.

Posted by: Van B Nov 4 2021, 03:59 PM

motor is confirmed dead and locked up. Doesn't respond to 12v direct and doesn't even want to turn by hand. Defroster lever lives up, but doesn't blow a large volume of warm air. It's hot but not much volume.

Other things maybe be missing sure. but I'll work through those as I go. Right now, I'm trying to figure out the best solution for a quality heater blower rebuild.

Posted by: Superhawk996 Nov 4 2021, 05:24 PM

Sometimes things are just plain worn out.

These really simple DC motors used in both the rear and the front fresh air box don't really lend themselves to rebuilds.

If you really want to stay on the rebuild path your best bet is going to be to find a very similar DC motor and adapt it to the impeller and housing.

Not saying it can't be done but if you've got one that is seized, that isn't a great starting point. If you want to see how badly this can go, see post #55. Yes, it's a front air box motor but the principle is about the same. Sometimes it can be done, sometimes it's a lost cause.

http://www.914world.com/bbs2/index.php?showtopic=351152&st=53

Posted by: 914Sixer Nov 4 2021, 06:17 PM

URO makes a blower assembly for less that $90 depending on where you shop.


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Posted by: rhodyguy Nov 4 2021, 06:40 PM

The air flow from the engine cooling fan should provide ample heat if the heat exchangers don't have gapping holes in the surrounds and everything else is intact. Try clamping some rubber caps on the J tubes and see what happens.

What Rob wrote re the dash sliders.

Posted by: wonkipop Nov 4 2021, 07:18 PM

true

but the heater lever between the seats is also doing that typical VW heath robinson contraption where its pulling the cables to the heat control boxes on the heat exchangers.
could be the heater control boxes back there are clagged up on Vans car, corroded shut and not working to let heat flow through.

agree on engine bay blower. its really there to do full blast windscreen defrosting.
hell, they got so cheap on 74 model years they only did the one hose fan biased to the drivers side!

i've got the whole system working nice on my car (74 1.8 same as Vans) and must admit i rarely pull the lever up between the seats all the way to engage the blower fan. gets way too hot.
the usual bleed off the engine cooling fan casting usually is enough to blow the hot air through.

could also be that the two flaps off the engine blower casting itself are clagged shut.
you have to get the piece of tin ducting off that goes to the heat exchanger to check those flaps.

those flaps and the heater control boxes off the end of the heat exchangers are the most likely things to be not operating and be stopping the heat flow.

its a nice idea to rebuild the engine bay blower, but its not going to be stopping a good flow of heat into the car. they didn't even have engine bay blowers on type 3s and type 1s and the bleed off the engine cooling fan was enough to incinerate your ankles as it came out of the little vents down in the sills on those VWs. i remember. the whole thing worked pure and simple off the cable operated levers between the seats (but was very dependent on engine revs - i guess the blower fan evened it all out).

Posted by: TonyA Nov 4 2021, 07:18 PM

Not an expert....but what about the cooling flaps that are operated by the thermostat?
If they are locked open than no heat or at least not much heat will go into the cabin. Am I correct or way off base?

Posted by: wonkipop Nov 4 2021, 07:23 PM

just means the car is slower to warm up.
won't effect the heater operation once the engine is warmed up.

the bleeds for the heater are way down at the bottom of the fan casting and rectangular in shape. hidden behind the sleeve joint for the air duct joiner to the heat exchangers are little flaps (or should be). they need to be free to move. air flow blows them open.