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FIXED - No Heat Issue(Only A/C and outside temp air) blowing from all vents

71K views 14 replies 11 participants last post by  samosali 
#1 ·
If you have an issue where your car stopped blowing warm or hot air (no matter what temperature or vents you select),
you most likely have the CHANGE OVER VALVE going bad.

*** Understand this problem is something DAS/STAR is not able to diagnose and scan as faulty.

This is only for vehicles with "No Heat" issue. In this condition, A/C-cold air and outside air work as they should. Problem is noted when heat fails to deliver on cold days/morning/evening when requested by the driver/passenger. Operator selects heat but gets whatever temperature air is outside.


The change over valve, controls how much (hot) coolant should go through the heater core. When this goes bad, the coolant going to the heater core is blocked, thus not heating up the heater core = no heat.

___
The part is located under the windshield wipers, behind the firewall cover (look at pics)

Firewall cover pulls up after removing the engine compartment rubber seal (very easy to do)

Get some hoes clamp pliers (I didn't have one so i used some old pliers that worked with some effort) and disconnect the old Valve/coolant clamps away.

**YOU WILL MOST LIKELY BREAK THE OLD VALVE INLETS. They are easy to break but the good news is you don't need the old valve anyway. If they break, make sure you don't have any plastic pieces inside the tubes.

You will loose some coolant. I lost and refilled less than a gallon 50/50 antifreeze.

You might have to fill the tank up more than once as the thermostat opens up.

If you have any questions let me know.
OEM part cost me $65 online

Mercedes R230 W216 W221 CL550 CL600 CL63 Genuine Heater Control Valve | eBay

GOOD Luck (You saved yourself $400+ dollars)
 

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#5 ·
Arlind86, Thanks for posting these instructions. I have a 2008 S550 that I recently bought, this was the first time I drove it in the winter cold weather, the heat was always working but after driving to the store I parked the car in the parking lot and the heat suddenly stop working, it was only blowing cold air. Is it possible that my Heater Control Solenoid Valve is defective and is this a easy repair job as you described, any help would be appreciated, thanks
 
#10 ·
Any info on the w222 yet. Same problem first dealer charged me for a software update. Didn’t work. Then charged me for problem being low coolant but not low enough for low coolant light to come in. Also didn’t work. Usually stops working when I turn ac on and then try to turn heat back on
 
#11 ·
If you have an issue where your car stopped blowing warm or hot air (no matter what temperature or vents you select),
you most likely have the CHANGE OVER VALVE going bad.

*** Understand this problem is something DAS/STAR is not able to diagnose and scan as faulty.

This is only for vehicles with "No Heat" issue. In this condition, A/C-cold air and outside air work as they should. Problem is noted when heat fails to deliver on cold days/morning/evening when requested by the driver/passenger. Operator selects heat but gets whatever temperature air is outside.


The change over valve, controls how much (hot) coolant should go through the heater core. When this goes bad, the coolant going to the heater core is blocked, thus not heating up the heater core = no heat.

___
The part is located under the windshield wipers, behind the firewall cover (look at pics)

Firewall cover pulls up after removing the engine compartment rubber seal (very easy to do)

Get some hoes clamp pliers (I didn't have one so i used some old pliers that worked with some effort) and disconnect the old Valve/coolant clamps away.

**YOU WILL MOST LIKELY BREAK THE OLD VALVE INLETS. They are easy to break but the good news is you don't need the old valve anyway. If they break, make sure you don't have any plastic pieces inside the tubes.

You will loose some coolant. I lost and refilled less than a gallon 50/50 antifreeze.

You might have to fill the tank up more than once as the thermostat opens up.

If you have any questions let me know.
OEM part cost me $65 online

Mercedes R230 W216 W221 CL550 CL600 CL63 Genuine Heater Control Valve | eBay

GOOD Luck (You saved yourself $400+ dollars)
Can you fix my heat on the s550 Benz call me at 9292479351
 
#12 ·
If you have an issue where your car stopped blowing warm or hot air (no matter what temperature or vents you select),
you most likely have the CHANGE OVER VALVE going bad.

*** Understand this problem is something DAS/STAR is not able to diagnose and scan as faulty.

This is only for vehicles with "No Heat" issue. In this condition, A/C-cold air and outside air work as they should. Problem is noted when heat fails to deliver on cold days/morning/evening when requested by the driver/passenger. Operator selects heat but gets whatever temperature air is outside.


The change over valve, controls how much (hot) coolant should go through the heater core. When this goes bad, the coolant going to the heater core is blocked, thus not heating up the heater core = no heat.

___
The part is located under the windshield wipers, behind the firewall cover (look at pics)

Firewall cover pulls up after removing the engine compartment rubber seal (very easy to do)

Get some hoes clamp pliers (I didn't have one so i used some old pliers that worked with some effort) and disconnect the old Valve/coolant clamps away.

**YOU WILL MOST LIKELY BREAK THE OLD VALVE INLETS. They are easy to break but the good news is you don't need the old valve anyway. If they break, make sure you don't have any plastic pieces inside the tubes.

You will loose some coolant. I lost and refilled less than a gallon 50/50 antifreeze.

You might have to fill the tank up more than once as the thermostat opens up.

If you have any questions let me know.
OEM part cost me $65 online

Mercedes R230 W216 W221 CL550 CL600 CL63 Genuine Heater Control Valve | eBay

GOOD Luck (You saved yourself $400+ dol
If you have an issue where your car stopped blowing warm or hot air (no matter what temperature or vents you select),
you most likely have the CHANGE OVER VALVE going bad.

*** Understand this problem is something DAS/STAR is not able to diagnose and scan as faulty.

This is only for vehicles with "No Heat" issue. In this condition, A/C-cold air and outside air work as they should. Problem is noted when heat fails to deliver on cold days/morning/evening when requested by the driver/passenger. Operator selects heat but gets whatever temperature air is outside.


The change over valve, controls how much (hot) coolant should go through the heater core. When this goes bad, the coolant going to the heater core is blocked, thus not heating up the heater core = no heat.

___
The part is located under the windshield wipers, behind the firewall cover (look at pics)

Firewall cover pulls up after removing the engine compartment rubber seal (very easy to do)

Get some hoes clamp pliers (I didn't have one so i used some old pliers that worked with some effort) and disconnect the old Valve/coolant clamps away.

**YOU WILL MOST LIKELY BREAK THE OLD VALVE INLETS. They are easy to break but the good news is you don't need the old valve anyway. If they break, make sure you don't have any plastic pieces inside the tubes.

You will loose some coolant. I lost and refilled less than a gallon 50/50 antifreeze.

You might have to fill the tank up more than once as the thermostat opens up.

If you have any questions let me know.
OEM part cost me $65 online

Mercedes R230 W216 W221 CL550 CL600 CL63 Genuine Heater Control Valve | eBay

GOOD Luck (You saved yourself $400+ dollars)
Hi,

I have the exact symptoms as your description, i.e. No Heat @ vents etc. The link that you listed does not work anymore. Can you help me with the link to the OEM part? Is it called the "Change Over valve" or "Heater Control Valve"? Please help. Thank you so much in advance.

Michael S
 
#15 ·
Good. But nobody described exactly how the valve behaved. Logically some outputs from it are cold if valve is broken ... but nowadays one cannot be sure if this is really true. Namely, cooling/heating system is based on velocities of fluid and who knows which physical quantities else, so sometimes a simple logic is not correct. In another words I certainly believe that the valve was bad but I would like to hear what exactly was bad and how was it shown in practice except non functional heating. And one more thing, is all this "non heating" about front heater, rear heater or both of them? Thanks.
 
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