[h2pmr]

87 S4 interior fan motor seized up, so thought a fairly easy fix via a Volvo 850 fan motor as on a recent RL thread, but sadly they are not the same.
the Volvo one is 3mm smaller in diameter and looks totally different
i don't know if its just the 87 thats different or all RHD versions, but as mine is different i will start a thread on it which might help someone.
this is the Volvo version


this is the one i have, and the rust shows why its seized up




Bosch part number of my motor is 0 130 107 098 which is NLA


the genuine one on the RL thread has splines on the shaft to hold the blades to it but mine does not.
looking at the picture of my shaft above - no sniggering in the back there- it has a flat section, yet my blades are still just a full round hole + the blades had the below small metal clamp fitted to give extra clamping force between blade and shaft.


so why have the flat on the shaft?
my guess is that the motor Porsche used for the interior fan was actually designed by Bosch as a radiator fan motor with the radiator fan blades being made with a flat in the hole of them, thus the blades could never turn on the shaft + its a very substantial motor for just an interior fan

so just need to find a radiator fan motor from the 80's that looks the same.
will keep looking but if anybody finds one please post on here and i will give it a go.

cheers
Phil

[h2pmr]

much, much searching and cross referencing i THINK i have found a new one from Bosch
but until i get it, fit it and it works will not know for sure.
should be here in a week'ish
fingers crossed etc.
cheers
Phil

[h2pmr]

now onto the fan resistor, on the plus side it looks like its a new'ish one.
but has been close to becoming a "thermal incident"
after 10 mins of cutting and gentle levering the melted on connector is off and resistor is still in one piece.
the usual fingers crossed it still works.
cheers
Phil

[h2pmr]

while i wait for the motor to arrive i thought i would give the housing a good clean.
removed the bottom housing to just leave the main body, pictures below are both sides of it



then i looked at the top housing that holds the motor and the bottom housing that bolts to the body......



then it dawned on me that the only difference between LHD and RHD versions is that the motor and base are fitted the other way around.
tried it and sure enough the base and top fit perfectly in either side of the main housing, both sizes of screws line up perfectly on either side
the metal mounting tab has its mirror image on the other housing that would just need swopping , below.
even has the predrilled hole with a blanking rivet in it


very very impressive design by the Germans.

cheers
Phil

[h2pmr]

looking at the resistor i noticed its the 89+ version, so asked local OPC if they could still get the upto 89 version 92861810101 and sure enough they are and with discount for £125 inc tax
i thought they were NLA, but goes to show always check with OPC to be sure.
still waiting for the potential drop in replacement to arrive, should be next weekends job
cheers
Phil

[worf]

… and sure enough they are and with discount for £125 inc tax

hmmm… skeptical… unless that OPC had an old one on the shelf.

[h2pmr]

arrived from Germany yesterday, but must only be able to get the 00
cheers
Phil

[h2pmr]

new Bosch motor arrived yesterday, the body is the right size for the plastic housing and the shaft is the right dia for the blades but the base of the motor does not have enough metal to bolt it to the housing
you can't win them all, God loves a trier etc.

i have another version coming in a week'ish so fingers crossed again
cheers
Phil

[h2pmr]

this one is looking a better option as it uses the exact same fan blades, same part number stamped on this one as the Porsche one, and in more plentiful, cheaper supply than the Porsche one
need to press the blades off tomorrow to see what slight modifications need doing, but its looking very promising.
cheers
Phil

[h2pmr]

all now back together and working perfectly
my next post will be a how to with pictures, very easy to modify to make it fit,
i guess these BEHR fan motors are fitted to some LHD vehicles.
if 2 bolts hold the motor to the housing its this type- picture below, if only 1 bolt its the other version as on the RL thread
teaser pictures below
but i guess the most important part is what the motor is:
its from a Merc W116 , which comes with the wires going directly into a very very similar fan motor resistor, the new one pictured below is the Porsche one which is still made to accept the wiring loom if it was supplied on a Merc.
must have shared more than the auto box with Merc
Merc part number A0008358102
Bosch part number 0130107011
cheers
Phil

[h2pmr]

so you have got your BEHR type interior fan motor out of your car, as its seized up, smells of burning, squeaks, rattles bangs etc and you need a new motor, but genuine ones are NLA.

here is what i did.
get the fan motor from a Merc W116 part number A0008358102 and its Bosch part number is 0130107011
which looks like the below


its an identical motor to the 928 one except for 3 things
the vent tube sticking out of the side needs to be cut off flush with the body of the motor
is soft metal so can easily be cut with a hacksaw BUT i also used a high power vacuum cleaner very close to the cutting so as to stop as many filings as possible entering the motor.

next remove the fan blades from the motor
remove the sprung metal clamp, circlip pliers or large flat bladed screw driver and GENTLY work it up an off, dont open it up to much as it will loose its clamping force
+ picture shows how much shaft sticks out of the blades, so needs to go back in the same position.


blades are still a tight fit on the shaft and if you have a press its easy to remove them, but a few taps with a hammer and drift should remove them.

next need to cut off the metal surround


i measured approx 15mm down from the top and covered all in masking tape again to stop any metal filings getting into the motor.
once cut off you can then fit the motor back into the housing so looks like below - disregard the wires-


once the motor is in the housing make sure the motor is in the middle of the center hole in the housing, as pictured below


then the 3rd difference between the Merc motor and the Porsche on is the Merc does not have the threaded holes for the 2 bolts to hold it in position.
so mark the body of the motor through the 2 holes when its as pictured above and the remove the motor from the housing

use a very thin screwdriver and gently put it in the bolt holes of the Porsche motor and you will find you don't have much room behind the motor casing so get a 3mm drill bit and snap it so it fits in the drill approx 5mm as pictured below


then drill where you marked the screw holes, again using a vacuum to stop as much as possible the drillings getting into the motor.
then you need to tap the holes to M4 thread, again remembering not to go to far into the motor, use a plug tap



then refit the blades + its clamp, fit the motor and bolt in place + small amount of loctite on the bolt threads


now i know what to do the next one would take approx 1 hour to swop motors, which would include a good cleaning of the motor housings.
hope this helps someone
cheers
Phil

[h2pmr]

now fully installed + new wiring connector fitted and the old resistor still worked ok

after cleaning the 35 yrs worth of leaves and rubbish out of the scuttle area i had a quick look at the A/C evaporator and was shocked to see it was totally blocked with 35 yrs worth of air blowing through it, a lot of it looked like foam particles, some of which must have come from the seal around the rubber join.
took a lot of compressed air and vacuuming to get it clean.

if you ever remove the heater motor or think there is not actually much air being blown through the air vents into the cabin, i would strongly advise to clean the evaporator.
cheers
Phil