Heater thermostat repair / replace ?
I have been having a good poke around under the dash tonight & noticed my heater thermostat unit ( valve) wasn't fixed to anything , thus the heater control being a bit uneffective as the cable didn't open or shut the thermostat :roll:
Anyway, whilst looking at this unit I noticed it is leaking coolant , which means it looks like I have found the source of my damp carpets :D
The unit is leaking around one of the spring clips ( do these hold the unit together ? ) . Is the unit repairable or should I try & source a new one?
When replaceing / removing the unit do I need to drain down the coolant from the whole system?
Sorry for the questions, but all my experience is with aircooled cars :wink:
Hi I suggest you take a closer look at this valve..from your description it sounds like the flowvalve part of the heat increase/decrease control on the facia.when you operate the control on the facia it should rmove a cable to rotate a gate inside the valve letting hot water be pumped through the heater matrix. the valve should on a solid mount so that it does not move when you operate the control on the facia.the leak may be from the hoses connected to the valve or the body of the valve.once the source is determined you should partially drain the water system to below the level of the heater hoses then disconnect the hoses from the valve body .it is purely a manual function. no thermostat is involved.parts are available from MB./. hoses unless preformed may be obtainable from general car parts vendors
Have a good look at that area with the heater controls in different positions. It may be that the cables are pulling the valve in such a way that the spring clips are not holding the hoses watertight. Either way, you'd need to get the valve mounted properly and I'd replace the spring clips with jubilee clips. This is a sign of accountants getting their dirty fingers into automotive engineering and design.
Ok, so have a look at the valve and see if there is a way to open it and replace a seal or something along those lines. Also get the part number from MB(or someone here might do on their EPC), see how much it is. With the PN, you may be able to source cheaper somewhere else or if 460**********, then there'll be plenty people here able to help you with good used ones.
Hi from your description it looks like the valve body is suspect...a new valve correctly installed should remedy the problem. Mercedes parts will need the vin No to identify the vehicle.I believe the valve is the same on the w & s 124 series cars (if you have a local breaker)
I have purchased a new valve from MB about 4y ago. It was about 45£. I bought a new one because the heater would not turn off completlyie in the summer noticable heat was coming from the vents with it switched off.
However, when I looked at the job of replacement I could not work out how to get it out of the vehicle. It literally was put in a position behind the dash and I worked out that the entire dash would have to be removed. So I abondoned the job. The leaking heat problem has got worse over the years and is most annoying in the summer.
The clips you describe do hold the valve together. They are easily removed to split the unit in 2. I guess that it could be sealed with silicon and reasembled.
Before you do anything more , see if you can reattach the unit to the body, my guess is that the previous owner attempted the job and couldn't do it either. I think in a LHD car you would remove the glovebox to reach it easily and on the RHD you are in trouble.
Please keep us informed.
I'll post the pn tonight after work.
PN 463 830 00 84
had another look today, this time with the engine running & it is pi**ing out of the valve.
I have removed most of teh panels under the dash & the valve is reasonably accessable.
So, do i have to drain down the whole cooling system before removing the valve?
PN 463 830 00 84
thanks for that :) I'll phone my local MB dealer tomorrow :)
must not be much antifreeze in the system if its leaking that bad so drain it down and start again with new antifreeze ..you may have to bleed the system to get the water flowing back through the heater when you have it all together again...
A word of advice to an aircooled man :wink:
Mix up your antifreeze top-up to the right strength with water and add like that, its a lot easier to keep your concentrate levels right, although if its been topped of continuously with water, ditch that idea and start again from scratch :)
Also be aware that antifreeze always used to be an effective paintstripper, dont know if thats still the case, but check under your carpets and wipe out accordingly, protect your floorpan paint :wink:
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Hi
Yes it is the valve connected to the cable from the heater controls.
It looks like someone has been behind the dash at some point & this valve has not been reattached to the manin body of the G wagen ( I can see the mounting point.
I'll have another look, but I'm pretty sure the leak is not from the pipes. In fast the pipes & jubille clips look pretty new.
The valve unit has the metal clips on its main body, one of these clips is showing signs of white corrosion etc & this is where the coolant leak is. It appears as if the leak is coming from where the two halves of the plastic valve body join