Heater Blower Motor, How to remove it for replacement Options

[sburns1967]

I have a 1973 914/4 2.0 which is is partially disassembled.

It came with two hot air blowers:

Single Port - Working Motor
Dual Port - Dead Motor

In 1973 there was apparently a switch between the dual outlet blower to a single outlet with a Y pipe.

I was thinking I would like to use the dual outlet one so I thought I would swap in the working motor.

Two questions:

1) Does the dual outlet unit provide better heat flow through the heat exchangers than the single outlet with a Y connector? Any pointers to pictures of each type mounted/hoses?

2) How to remove the motor:

Removed the 6 screws on the motor flange
Removed the nut/washer from the cage fan

After doing so I can get zero movement from the motor from the housing. Even prying between the flange and the housing nothing moves.

Does anyone know if there is some kind of adhesive between the motor flange and the housing? If so do I apply a little heat maybe?

Thanks in advance
Scott

[chmillman]

I have a 1973 914/4 2.0 which is is partially disassembled.


In 1973 there was apparently a switch between the dual outlet blower to a single outlet with a Y pipe.

Actually the "Y" pipe was just an accessory added by some dealers using VW parts. It was not stock from the factory. When they switched to a single outlet blower, they just used one hose on the driver's side. The passenger side had no hose going to it and was capped off. Some people have restored the two hose system using either found old Y junctions or 3D printed new ones.

[Olympic 914]

If you have good heat exchangers, there will be enough heat coming into the cabin with the single outlet blower.

I added the Y pipe and hose to the passenger side, but rarely pulled the lever far enough to activate the blower. ( it only comes on at about 3/4 to full on the lever) didn't really like the looks and additional clutter of the hose going to the passenger side. So i removed it and capped that side. As it came originally.

I get plenty of heat as it is.

[wonkipop]

in terms of what the factory did with the blowers.
as noted above. single hose blower for 73/74 to drivers side heat exchanger.
single hose blower for 75 up to late nov/early dec 74 production date.
y junction adaptor to single outlet blower with twin hoses starts after that to end of production dec 75.

all of the blowers are parts bin components from the VW 411/412.

the early (70-72) twin hose blowers are from the 411 2 and 4 door sedans.
the 73-74-early 75 single hose blower fans are from the 411/412 variants (squarebacks) but without the squareback y adaptor. then later after nov/dec 74 using the y adaptor from the squareback.

when installed in the 914 the later twin hose set up used some stand off clips to keep the right hand hose clear of restricting the air flow to the cooling fan. i think this is an important detail. i have seen a few 73/74 cars that have had twin hose set ups installed by owners that lack the positioning clips and the hose restricts that gap that the cooling fan draws through. this was not an issue with the VW sedans/variant as the cooling fan drew air through a rubber boot and dedicated air duct in the bodywork.

as to why the 914s got only a single hose fan for a couple of years i would speculate that possibly it was felt beneficial to bias the fan forced air flow to the drivers side to assist with windscreen demisting in the small cabin of the 914 and ensure the driver side portion of the windscreen demisted faster. then later decided this was unnecessary.
its possible that the later style heat exchangers in the 75 models might have delivered more heat to the cabin than the earlier heat exchangers and the biassed fan boost was less critical for deep winter demisting. the exhaust system in that last year of production was itself a thicker guage pipe inside the heat exchanger acting as a kind of thermal reactor to deal with unburnt hydrocarbons as they exited the combustion chamber. it was designed to retain heat in the first section of exhaust pipe to burn those hydrocarbons and so probably generated greater heat inside the exchanger.

i am sure there would have been a rational reason they reverted back to a twin hose.
maybe what i put foward above.

in any case i have never found the single hose version in my 74 inadequate.
but l live in australia. hardly a severe winter climate. (IMG:style_emoticons/default/biggrin.gif) (IMG:style_emoticons/default/beerchug.gif)

[dtmehall]

I have always found that the heat from a single hose in my 73 was sufficient, even here in the great white north!

[sburns1967]

Thanks for the info and detailed review of the two setups/history.

I may just go with the splitter kit from Auto Atlanta to split off my working single port blower and drive both heat exchangers.

With my wife using the heated seats in her cars, even when it is 35C in the summer, I can use all the heat I can get.

Scott

[DRPHIL914]

Thanks for the info and detailed review of the two setups/history.

I may just go with the splitter kit from Auto Atlanta to split off my working single port blower and drive both heat exchangers.

With my wife using the heated seats in her cars, even when it is 35C in the summer, I can use all the heat I can get.

Scott

Thats how mine is set up, i do like having the heat coming out of both sides if you have a passenger. My car is a 75 the fan works fine it is the single outlet with splitter clamped on the end. my only issue is in the summer i cap them off and disconnect the lower tubes because the flapper box seals are not fully sealing so hot air gets past even in the closed position, not desired in the 90 degree heat

[sburns1967]

I have received the splitter from AA and tried it on my single outlet fan. Output is poor.
Regardless of which way I place the splitter the flow is minimal.

Moving the exact same motor/fan assembly over to the dual outlet housing the output is extremely powerful on both outlets.

I have an anemometer I am going to try this week to measure the output in all the combinations. I will post my results.

Initial thought is if you want really good heat you will want the dual outlet housing from the earlier cars.

[sburns1967]

I have a 1973 914/4 2.0 which is is partially disassembled.

It came with two hot air blowers:

Single Port - Working Motor
Dual Port - Dead Motor

In 1973 there was apparently a switch between the dual outlet blower to a single outlet with a Y pipe.

I was thinking I would like to use the dual outlet one so I thought I would swap in the working motor.

Two questions:

1) Does the dual outlet unit provide better heat flow through the heat exchangers than the single outlet with a Y connector? Any pointers to pictures of each type mounted/hoses?

2) How to remove the motor:

Removed the 6 screws on the motor flange
Removed the nut/washer from the cage fan

After doing so I can get zero movement from the motor from the housing. Even prying between the flange and the housing nothing moves.

Does anyone know if there is some kind of adhesive between the motor flange and the housing? If so do I apply a little heat maybe?

Thanks in advance
Scott

I was finally able to separate the old motor from the dual outlet body with a little heat. It appears to have been bonded somehow. Not sure if that was a factory setup or a PO.

[WFG]

On the early model the hose going to the passenger side on defrost also
supplied the center vent
William

[Osnabruck914]

Move to Florida. I removed my entire blower system and I still get more than enough heat for the climate here. Kept all the parts, of course.

Osnabruck914

[dtmehall]

except when the iguanas fall down from the cold

(IMG:style_emoticons/default/evilgrin.gif)

[chmillman]

I have received the splitter from AA and tried it on my single outlet fan. Output is poor.
Regardless of which way I place the splitter the flow is minimal.

Moving the exact same motor/fan assembly over to the dual outlet housing the output is extremely powerful on both outlets.

I have an anemometer I am going to try this week to measure the output in all the combinations. I will post my results.

Initial thought is if you want really good heat you will want the dual outlet housing from the earlier cars.

That is definitely possible. The single outlet version forces all the air to go through one tube before splitting it back in two, creating more resistance to the airflow and probably reducing the efficiency of the fan.

[wonkipop]

I have a 1973 914/4 2.0 which is is partially disassembled.


In 1973 there was apparently a switch between the dual outlet blower to a single outlet with a Y pipe.

Actually the "Y" pipe was just an accessory added by some dealers using VW parts. It was not stock from the factory. When they switched to a single outlet blower, they just used one hose on the driver's side. The passenger side had no hose going to it and was capped off. Some people have restored the two hose system using either found old Y junctions or 3D printed new ones.

no --- not quite. i say this politely, not a smart arse. (IMG:style_emoticons/default/biggrin.gif)

our L jet research got to the bottom of it.

first of all the early cars just had a straight up 411 blower motor in the straight up position it was mounted in - in a 411 fast back or 4 door. twin hoses. no y junction.
fan had two outlets rather than a single into a y.
mounted off the fan casting.

in 73 (i think - 72?) they went to a single fan outlet. completely unique to 914. biased to drivers side. not mounted off fan casting but off left side of engine bay.
probably a functional engineering idea to assist with demisting the windscreen in front of driver in small 914 cabin?

this persists through 73 and 74 and part way through 75 model year.
then in late 1974 calendar year (75 model year) around about late nov 74/dec74 they begin to fit the cars with the twin hose set up again. but they keep the single hose outlet fan on left side of engine bay. thats when the adapter comes in. and it all comes from the 412 variant heater blower set up.

they use parts from the VW 412 variant - y splitter and long hose to right hand side of car.

now that is what the factory did.

in the half century since all sorts of things have been done to the cars.
but it went down that way.

twin hose with twin outlet fan in early 914s using the twin outlet fan from 411 sedans.

then single hose outlet fan - unique to 914s from 73 through to early 75.
but the fan unit came from the VW 412 variant minus the splitter.

then same fan (which came from 411/412 variant) but fitted with variant splitter and two hoses until end of production.

(IMG:style_emoticons/default/beerchug.gif)

which one works the best?

flip a coin.
they all worked in the VW 411/412.
but there is a problem in a 914 with such a small cabin and with two people in it and the top on during a cold wet night with demisting?
not that i would know because i never drive my 914 in those conditions any more - just top off only and beautiful aussie sunny mornings. so who knows which one works best.

my guess. none of them. it was a problem until the end of production? (IMG:style_emoticons/default/biggrin.gif) (IMG:style_emoticons/default/beer.gif)
why they kept fiddling with it?