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  #1  
Old 11-16-2018, 07:54 PM
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W115 heater blower motor

Alright so the heater blower motor does not work in my 72 220D.

AC fan works just fine but heres the catch, when I turn the ac temp knob on the console all the way to the left (least cold setting) the cars engine will not turn off with the key/gorilla knob. I'm assuming this has to do with vacuum?

I pulled the air intake grille under the wipers today and to my surprise it was pretty clean under there. I was able to turn the blade (although it wasn't easy) and also got some lubricant shot up in there.

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  #2  
Old 11-16-2018, 08:04 PM
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On my 76' 240D there was a changeover switch above the accelerator pedal. It controlled which blower motor received power and there was a 2 fuse fusebox on the firewall under the hood slightly off-center toward the passenger side for the blower motor(s).

IIRC the changeover switch was vacuum controlled also??? But I don't see why the car wouldn't shut off as that is mechanical to the injection pump.

Hope this helps, Good Luck!!!
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Old 11-16-2018, 10:55 PM
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Quote:
Originally Posted by mabbonizio View Post
Alright so the heater blower motor does not work in my 72 220D.

AC fan works just fine but heres the catch, when I turn the ac temp knob on the console all the way to the left (least cold setting) the cars engine will not turn off with the key/gorilla knob. I'm assuming this has to do with vacuum?

I pulled the air intake grille under the wipers today and to my surprise it was pretty clean under there. I was able to turn the blade (although it wasn't easy) and also got some lubricant shot up in there.
Likely a vacuum leak in the HVAC system causing inadequate vacuum in the vacuum controlled engine shutdown system.
http://eva2.homeip.net/W115/program/Climate/83-545.pdf

http://eva2.homeip.net/W115/program/Engine/615/07-150.pdf
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  #4  
Old 11-16-2018, 11:00 PM
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The 220/240D does not have vacuum shutoff. You could have a vacuum leak causing the switch not to activate above the gas pedal, but it would not affect the shutoff of the car. Usually it will start off with heater blower motor, and when switch is activated it will switch to ac blower. If it does not blow anything, then you turn ac knob and it starts blowing, then you would be correct about it being heater blower motor.
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Old 11-16-2018, 11:43 PM
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Originally Posted by MB140300SD View Post
The 220/240D does not have vacuum shutoff. You could have a vacuum leak causing the switch not to activate above the gas pedal, but it would not affect the shutoff of the car. Usually it will start off with heater blower motor, and when switch is activated it will switch to ac blower. If it does not blow anything, then you turn ac knob and it starts blowing, then you would be correct about it being heater blower motor.
I know vacuum leaks can cause shutdown problems in OM617 MB diesel models that I have owned.
After a quick read of the FSM, I interpreted that the vacuum box on the back of a W115 IP was for engine shutdown.
I may have misunderstood the information in the FSM, as I have not owned or worked on this model previously.
http://eva2.homeip.net/W115/program/Engine/615/07-220.pdf
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Old 11-17-2018, 07:31 AM
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Hi Guys, thanks for all the help. I guess I should have clarified, 72 220D with a later model 240D motor swapped in so it does use vacuum to shut the engine off.
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Old 11-17-2018, 08:19 PM
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Quote:
Originally Posted by mabbonizio View Post
Hi Guys, thanks for all the help. I guess I should have clarified, 72 220D with a later model 240D motor swapped in so it does use vacuum to shut the engine off.

So you swapped in an engine out of a 123? What did you do about the oil filter housing? Anyway, if you do have vacuum shutoff then yes, you have a leak somewhere.
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Old 11-17-2018, 09:46 PM
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Originally Posted by MB140300SD View Post
So you swapped in an engine out of a 123? What did you do about the oil filter housing? Anyway, if you do have vacuum shutoff then yes, you have a leak somewhere.
I did not, I presume the previous owner did. It is an OM616 from a w115 240D. Oil filter housing is on the bottom.
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Old 11-17-2018, 11:05 PM
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115 240D's had the same oil filter set-up and manual fuel shut-off...yours is definitely vacuum? The shut-off knob doesn't make sense if it is vacuum.

Is this problem new since you have owned it?
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Old 11-18-2018, 08:55 AM
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Quote:
Originally Posted by Sugar Bear View Post
115 240D's had the same oil filter set-up and manual fuel shut-off...yours is definitely vacuum? The shut-off knob doesn't make sense if it is vacuum.

Is this problem new since you have owned it?
Hmm, is it possible someone swapped a W123 injection pump onto it?

I have a W123 240D and the injection pump is definitely the same set up. If I remove the vacuum line going to it the motor will not turn off.

Another peculiarity is that the intake manifold is I believe from a W123 240D, it has the same air cleaner housing as my W123 240D and I have not seen one of those on a W115.

Perhaps the engine itself is from a W123 and the PO swapped the oil filter housing from a 115 to make it fit?

Also, the motor doesn't turn off by pressing in the gorilla knob only.

You have to press the gorilla knob in and then switch the key off and it will shut off.

Been doing this ever since I got it.
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Old 11-18-2018, 10:25 AM
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Interesting...maybe some swaps were done. If there is a vacuum hose to the changeover switch above the go pedal, plug it and see what happens re: shutting the engine down. It doesn't take much of a leak to stop the vacuum engine shut-off.

Check the inline vacuum filter near the firewall, engine side (looks like an early VW Bug fuel filter) for cleanliness and the that the port off of the brake booster vacuum hose to the vacuum system is not restricted.

How well do the trunk and door locks work and how crisp is the shut-off when the AC is in off mode?
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Old 11-18-2018, 10:35 AM
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so the trunk and door locks do not work at all and I presumed the car just didnt have vacuum locks since I didn't see any lines going to the doors.

With the AC blower off but "colder" switch turned all the way to the right (coldest setting) it shuts off fine.

With the AC blower off but "colder" switch turned all the way to the left (I suppose warmest setting) it won't shut off at all.
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  #13  
Old 11-18-2018, 10:54 AM
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Sounds like a vacuum leak at the AC control knob or a pod that it controls. Do an image search on "W115 AC Switch" to see the vacuum ports and the capillary tube that goes to the AC evaporator on the switch.

IIRC it had vacuum door and trunk locks from the factory. Hopefully another member will confirm their existence.

Good luck and keep us posted!!!
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Old 11-18-2018, 08:02 PM
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Quote:
Originally Posted by mabbonizio View Post
I did not, I presume the previous owner did. It is an OM616 from a w115 240D. Oil filter housing is on the bottom.

It that case it should have manual shutoff. Are you sure it has a vacuum shutoff? There is a governor on the back of the IP that has a line running to the intake but it is not a vacuum shutoff valve. If you really do have vacuum shutoff it sounds like somebody somehow swapped out the IP with a later one.
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  #15  
Old 11-18-2018, 08:38 PM
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Quote:
Originally Posted by MB140300SD View Post
It that case it should have manual shutoff. Are you sure it has a vacuum shutoff? There is a governor on the back of the IP that has a line running to the intake but it is not a vacuum shutoff valve. If you really do have vacuum shutoff it sounds like somebody somehow swapped out the IP with a later one.
Positive it has a vacuum shut off valve, if I remove the one vacuum line going to the IP and turn the key to the off position the engine will just keep running. it is exactly the same as my 82 240D.

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