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DIY: Water (Heater) Valve Replacement

170K views 69 replies 36 participants last post by  mr_y82 
#1 ·
I'm going to change my water valve in a while, any tips how to bleed the system after finishing? Is it the same way as when the expansion tank is replaced?

DIY coming soon :craig:
 
#2 ·
Blowing hot/warm air when the HVAC is set to 16 degrees? My immediate thought was the water valve which opens/closes, allowing hot coolant in the heater core. I assumed the valve was stuck and would not close completely, hence allowing coolant flow in the core. I went ahead and bought a replacement valve from Tischer BMW (USA)

The old one as it was in the car


First I had to remove the airbox to allow some space to work.


Remove 3 push-lock pins for the air intake assembly


Unplug MAF and loosen the big clamp that holds the intake boot on the MAF


Remove the 2 x 10mm bolts that hold the airbox assembly in place


Airbox removed


Unplug the water valve connector


Pull the water valve out of its 3 rubber guides to reveal the 2 hose clamps screws. Use a flathead screwdriver to undo both screws, paying attention which is the upper and which is the lower hose.


The new water valve
Front:


Rear:


Coolant flow arrow


I placed a rag underneath the water valve to catch the coolant and pulled both hoses out. Then I immediately placed the new water valve and pushed both hoses back in place. Screwed both clamps and secured the valve in place. Plug the connector in the valve. Re-install airbox and MAF connector. Job almost done.


Since air was introduced in the system from the partial coolant loss, I bled the system just to make sure. Removed coolant cap, loosened the bleed screw, started the engine and set the heater temp to its highest setting (32 degrees Celcius) in full blast. Setting the temp in the highest setting would open the water valve allowing coolant flow in the entire system. I topped up the coolant with a 50/50 mix of BMW Antifreeze and distilled water so that the indicator would go to the top mark. As soon as bubble-free coolant started to come out from the bleeder screw, I tightened it, turned off engine and replaced coolant cap.


Job done. Now I have outside environment temperature air even when the A/C is off. I'll open the old water valve to see what actually failed. The heater valve connector wires were a bit exposed for some reason so I applied a generous amount of PVC tape for protection.
 
#10 · (Edited)
Paraklas your a champ. But I have a question for you.

My upper radiator hose failed recently, spilling coolant EVERYWHERE over my engine bay. After this, I no longer had cold air, even at 16*c. Is it possible that coolant spilt on the heater valve, damaging it and therefore disabling cool air? If so, should I go ahead and replace this part?

Also, part # and $ would be great.

Cheers

edit: also i've noticed (if it helps with the diagnosis of my problem) - when the ac is set to lowest temp (16*c), the drivers side vents are *slightly* warmer than the passenger side (note that I drive a RHD car)
 
#13 ·
Great DIY!

I wanted to minimize coolant leakage/spillage during the change of the water valve - so I "clamped" the hoses leading to/from the valve with some needlenose pliers gently held tight with some twine. Not a drop of coolant spilled from the pipes. Note that I protected the hose from the sharp edges of the pliers with some shop towels.
 
#23 ·
I just finished mine. There were a couple of minor details that were different, probably because this is an M3 with HID's. The most significant - although it's not a big deal - is the HID ballast sits on top of the screws for the airbox, and the general layout of the airbox is different, but once you get past that it's pretty much identical. The burp/bleeder screw is in a different spot, too.

It looked like mine had been leaking at some point.

I took a picture of the old and new valve; it looks like the new one is a different rev.

I used a pair of 6" needle-nose vice grips, with duct tape on the jaws, to clamp off the hoses. I lost very little coolant, maybe a pint, tops.

This fixed my problem, and the a/c is once again cold.

The whole procedure took about an hour and a half, but I took my sweet time with it. If I'd flat-rated it I probably could have done it in 1/2 hour.

I owe paraklas a beer.

TLDR: M3 looks different, replacing the valve fixed the problem.
 

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#40 ·
I just finished mine. There were a couple of minor details that were different, probably because this is an M3 with HID's. The most significant - although it's not a big deal - is the HID ballast sits on top of the screws for the airbox, and the general layout of the airbox is different, but once you get past that it's pretty much identical. The burp/bleeder screw is in a different spot, too.
It looked like mine had been leaking at some point.
I took a picture of the old and new valve; it looks like the new one is a different rev.
This fixed my problem, and the a/c is once again cold.
TLDR: M3 looks different, replacing the valve fixed the problem.
the M3 version is different from the non-M ones. the M3 has a mini water pump for after-run cooling added to the Heater Valve unit. you can see the pump unit in the pictures of M3 vs. non-M. it could also have a leak from that source if someone just has leaking coolant as their issue.
 
#29 ·
hey

i replace the valve and its still doing the same if i clamp it the house it work fine so i did replace the valve worked for two sec and same thing again i took the valve out shoot power to it and the valve work put it back on and it dont work i checked the wire voltage and i get both side 12v i cant get it one should be - one + but the both wire on the connector that connects to the valve has 12V
 
#31 ·
i replace the valve and its still doing the same if i clamp it the house it work fine so i did replace the valve worked for two sec and same thing again i took the valve out shoot power to it and the valve work put it back on and it dont work i checked the wire voltage and i get both side 12v i cant get it one should be - one + but the both wire on the connector that connects to the valve has 12V
So what you're saying is you replaced the valve, but the problem still exists? Did you replace it with a new one or ???
 
#33 ·
Does anyone need a repalcment valve? I ordered a used one that was in excellent condition, and magically after it arrived, the one on my car started working again ....figures. In any event, I have a used one that is in excellent shape from an '06 m3.

PM me if you are interested

- Matt
 
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