W107 Heater Stuck On??

[roocarl]

please advise where ever i put heater controls I have hot air streaming into cabin?

 

[grober]

there are several possibilities but since you havn't supplied any model details-engine-date of manufacture its difficult to say. http://www.detali.ru/cat/oem_mb2.as...&L=765.701&CT=F&cat=048&SID=83&SGR=180&SGN=04 You may have the old vacuum operated water heater valve which has failed. Alternatively you might have an early version of the electrically operated " duovalve " If this fails/jams the symptom is continuous heat from system. Do a search for duovalve as there are several posts on these including a HOW TO REBUILD.

 

[Rasputin]

107 Heater Valve

please advise where ever i put heater controls I have hot air streaming into cabin?

Most 107 (as Grober said) have vacuum operated valve as the one on the pics. To remain closed it needs constant vacuum and the nearest non-return valve or the membrane inside the bell perish. To test the membrane disconnect the vacuum pipe to the bell and apply suction. If the valve closes then your next port of call is the vacuum reservoir or the first non-return valve.

 

[roocarl]

thanks for that , a couple of questions my car is a w107 1989 300sl where is the valve located? do i apply suction with my mouth? and how do i know if working does it click into place ?
cheers carl

 

[Druk]

It's here. Right rear bulkhead.
Disconnect the pipe at the rubber and suck it. The white lever will move 90 degrees. Stop the pipe with your tongue and it should hold position.

 

[alibally]

Drop The Lower Dash Side Panels. The Nuts For The Heater Controls Come Slack.

 

[roocarl]

tried those

Hi thanks for suggestions I have stripped front facia side console panels the nut on levers has not become loose ,I checked the .The vacuum operated valve does hold position indicating membrane is fine the next step you suggested was the reservoir of the non return valve?
where and how do i check this please ???
very gratefull for suggestions so far by way ?
Im keen at having a go myself just not an expert with these cars
cheers Carl

 

[Druk]

With engine running check operating dash levers actually makes white lever on valve work. If not then possible vacuum pipe off at dash. Facelift 107s have vacuum pump in boot to work door locks. The rest, heater valve, headlamp adjust only need to work when engine running so not sure if vacuum system actually has storage tank. Not sure of this point however.
Does the headlamp height adjust work, if not indicates possible vacuum pipe off at manifold.

 

[roocarl]

Thanks i will check that! I know with engine running the control levers were not moving the white lever by the vacuum housing
cheers Carl

 

[wobbly]

With engine running check operating dash levers actually makes white lever on valve work. If not then possible vacuum pipe off at dash. Facelift 107s have vacuum pump in boot to work door locks. The rest, heater valve, headlamp adjust only need to work when engine running so not sure if vacuum system actually has storage tank. Not sure of this point however.
Does the headlamp height adjust work, if not indicates possible vacuum pipe off at manifold.

My heater valve operates without the engine running, so I take it that the facelift also has a storage tank.

 

[roocarl]

Hi levers on dash have no effect on vacuum levers if engine on or off ,I checked headlight adjustment nothing happens and checked vacuum pipes still attached to levers on back of dash but there seems no pressure ,
I tied vacuum lever down to stop hot air which worked in stopping hot air ,
Then It snowed I was getting too cold and window would not demist !
So apart from attaching a piece of string to vacuum lever and routing through window im struggling to find a solution ??????????
Carl

 

[Druk]

The fact that the headlamp adjust is also not working suggests there is a pipe off or broken somewhere else. Manifold would be my first choice for a looking at. My car (earlier than yours) has a bundle of these pipes wrapped in polythene back right of engine room.
A temporary stop on the heat could be made by putting a brake line clamp on the input pipe to the valve.

(Flippant answer. Move North: no snow up here)

 

[Rasputin]

Hi levers on dash have no effect on vacuum levers if engine on or off ,I checked headlight adjustment nothing happens and checked vacuum pipes still attached to levers on back of dash but there seems no pressure ,
I tied vacuum lever down to stop hot air which worked in stopping hot air ,
Then It snowed I was getting too cold and window would not demist !
So apart from attaching a piece of string to vacuum lever and routing through window im struggling to find a solution ??????????
Carl

As Wobbly and Druk have pointed out, there seems to be vacuum loss causing vacuum operated devices to become inoperative. Having determined by your tests that the heater valve is in good condition you will need to check the vacuum system to locate the loss of vacuum. Below are a series of diagrams that may help you to trace components to check them out. There are located several Vacuum Check Valves that also perish (as per last pics below) and you could check them to ascertain that there is suction on one side and but not on the other. Your vacuum reservoir pipe may be disconnected or broken (under the o/s wheelhouse)

 

[roocarl]

bewildered

I thought I stood a chance till I saw all those vacuum diagrams ,
hmm I think I will remove airfilter housing to see if vacuum pipe has come away try the filters in the bagged up section near bulkhead and if that fails may have to take car to someone for help
Does anyone know a specialist near silverstone/banbury area?