# 2012 2.0T A3 bad coolant leak, please help?



## rodH (Aug 23, 2002)

Well, I had a problem last month that required me to replace an O2 sensor, now I have another problem.

Coolant was low a few weeks ago, and now it is low and draining quickly. After looking all over, I think I found the general area where it is leaking, but as I do a massive search I can't seem to find the part I am looking at (it is tight in there). 

Basically, as you trace the 2 largest hoses in the area, the upper and lower radiator hoses back to the engine, there is a plastic connector that they both attach to (these hoses run kind of parellel to each other). It appears that it is at the junction of the hoses and the connector, or more than likely the connector itself. I can squeeze one of the hoses and I can hear the air and fluid move around due to the leak. I have found that there are a lot of "flanges" that go bad, but when I search for that part it looks different. Anyone have any idea what part it could me? Maybe I just can't get a good enough view to match what I see online to figure it out, since it is so hard to see in there.

This is driving me crazy and the car is out of warrantee, so I kind of need to figure it out on my own (with the wisdom of vortex).

TIA


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## npace (Sep 3, 2012)

This?










http://www.ecstuning.com/Audi-A3-Quattro-2.0T/Engine/Cooling/ES281550/

Or this?










http://www.ecstuning.com/Audi-A3-Quattro-2.0T/Engine/Cooling/Water_Pump/ES2831229/

First one is the cylinder head flange, second is the water pump with housing. Both sound like they could be what you're describing. We need more info and if possible, a pic. Whatever the case, make sure you get new seals/o-rings to go with the part.


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## rodH (Aug 23, 2002)

npace said:


> This?
> 
> 
> 
> ...


THANK YOU!!!

It is for sure the bottom one, if it is leaking around the 2 tubes, does that mean the whole pump is shot, or just the housing, or perhaps just need new seals?

Having done a lot more research the past few hours, I realized that I made a mistake a few weeks ago and "topped it off" with non-Audi G12 coolant and it sounds like that can cause a lot more problems and may have lead to the leaks. It has only been driving a couple hundred miles since then, so hopefully not too much damage, where would I even start to learn how to repair or what is bad and what isn't?

TIA!!!!


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## rodH (Aug 23, 2002)

btw, I saw that pic several times before, but didn't think it was the item because all the pics have that smooth glossy coating, and the OEM piece in my car is more the cheap rough plastic finish and looks totally different, but as closer inspection, this is for sure the item.


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## vwlippy (Jul 17, 2001)

rodH said:


> THANK YOU!!!
> 
> Having done a lot more research the past few hours, I realized that I made a mistake a few weeks ago and "topped it off" with non-Audi G12 coolant and it sounds like that can cause a lot more problems and may have lead to the leaks. It has only been driving a couple hundred miles since then, so hopefully not too much damage, where would I even start to learn how to repair or what is bad and what isn't?
> 
> TIA!!!!


Definitely flush your system out really well since you mixed coolants. The sooner the better.


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## Audi_Mechanic (Mar 24, 2012)

The plastic coolant pump/distribution housing leak is common on the chain drive 2.0t. From what you describe with the two parallel radiator hoses it's what you need to replace. You might also need to replace the heater pipe & its seal that plug into the front of that pump. The drive gear bolt should be replaced as well as the small hourglass shaped pipe that connects the pump to the heat exchanger.


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## rodH (Aug 23, 2002)

Audi_Mechanic said:


> The plastic coolant pump/distribution housing leak is common on the chain drive 2.0t. From what you describe with the two parallel radiator hoses it's what you need to replace. You might also need to replace the heater pipe & its seal that plug into the front of that pump. The drive gear bolt should be replaced as well as the small hourglass shaped pipe that connects the pump to the heat exchanger.


GREAT!! So I can buy the plastic housing and just replace that instead of the motor and everything else that is included within the housing?


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## Audi_Mechanic (Mar 24, 2012)

Just buy the whole unit, no point in replacing individual components since they leak from every possible point.


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## rodH (Aug 23, 2002)

Audi_Mechanic said:


> Just buy the whole unit, no point in replacing individual components since they leak from every possible point.



Just had my mechanic buddy look at it. He said it is either the hose (top one?) or the housing, but hard to see for sure until he gets in there. So what do you guys typically see as the fault? And how can one figure it out easily without buying both parts? (I guess the hoses aren't cheap)


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## louiekaps (Aug 12, 2013)

If you google tsi water pump failure you'll learn that the water pump leaking is one of the most common failures on the 2.0 tsi motor across all vw makes. I can almost guarantee it isn't the hose and you need a waterpump. Make sure you don't have any oil leaking down on the pump.


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## Audi_Mechanic (Mar 24, 2012)

What's most common is that the plastic housing cracks at the port for the plastic pipe (heater circuit) that plugs into the front of it. Sometimes they leak at the small pipe that connects it to the heat exchanger/oil cooler, sometimes the coolant pump leaks at its shaft seal (behind drive gear), sometimes the fitting for one of the radiator hoses leaks (the fitting is replaceable). I've had to replace thermostats on a couple of them (warranty only pays for bare minimum repair), so just replace the whole unit since if you just make a repair to it, a new leak will occur somewhere else shortly. 

Some of the units have an extra electrical connector for something, so you will have to make sure you get the correct one.


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## rodH (Aug 23, 2002)

Bummer, mechanic installed Mfg Part#06H121026DD which is supposed to be the updated one with more metal parts and it still leaked. Bought the upper hose and that stopped the leak. BUT now I am getting a CEL because this new updated Mfg Part#06H121026DD doesn't have an area to plug into for the thermostat Sensor (must be a more passive thermostat?), so since I now have an open loop, I am getting the CEL. 

Now what? Is there a way to close that loop just to get my CEL off?


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## Evo V (Dec 29, 2010)

rodH said:


> Bummer, mechanic installed Mfg Part#06H121026DD which is supposed to be the updated one with more metal parts and it still leaked. Bought the upper hose and that stopped the leak. BUT now I am getting a CEL because this new updated Mfg Part#06H121026DD doesn't have an area to plug into for the thermostat Sensor (must be a more passive thermostat?), so since I now have an open loop, I am getting the CEL.
> 
> Now what? Is there a way to close that loop just to get my CEL off?


I also got a Rev. DD as a spare and the thermostat is there. Are you sure he plugged it in? It's on the upper left corner of the water pump if you looking from the front f the car, right underneath the intake manifold.


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## rodH (Aug 23, 2002)

Evo V said:


> I also got a Rev. DD as a spare and the thermostat is there. Are you sure he plugged it in? It's on the upper left corner of the water pump if you looking from the front f the car, right underneath the intake manifold.



Is this a different place that the old version?


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## Audi_Mechanic (Mar 24, 2012)

There's a small connector that plugs into the side of one the pipes for radiator hoses.

Who ordered the replacement pump, you or the shop?


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## rodH (Aug 23, 2002)

Audi_Mechanic said:


> There's a small connector that plugs into the side of one the pipes for radiator hoses.
> 
> Who ordered the replacement pump, you or the shop?


Me. So I am guessing it is the wrong part?


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## Evo V (Dec 29, 2010)

rodH said:


> Me. So I am guessing it is the wrong part?


Red arrow is pointing to the thermostat and the connector.


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## Audi_Mechanic (Mar 24, 2012)

Evo V said:


> Red arrow is pointing to the thermostat and the connector.


Red arrow is pointed towards the coolant temperature sensor.


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## Audi_Mechanic (Mar 24, 2012)

rodH said:


> Me. So I am guessing it is the wrong part?


Probably the wrong part. If the shop ordered the part, then they would be responsible for installing the correct pump. Since you supplied the part, then you might have a hard time getting the shop to install the correct pump for free. In order to get the old pump out, the mechanic would have had to unplug that electrical connector. If they installed it and called it done without dealing with that loose electrical connector, then you can say that it's their fault for not stopping and notifying you earlier that it's the wrong pump. 

A while back I had to replace a chain drive 2.0T engine on a 2011 or 2012 A3 because the cam bearing bridge check ball came apart, caused intake cam to jump timing and bend valves. The new engine came with the wrong coolant pump and the wrong oil pan. I had to wait a day or two for someone from audi to verify that it was the correct engine so I can install the correct pump & pan. I don't know why there's a difference, whether it's specific to the CCTA engine or the CBFA engine. I think one of them has extra emissions equipment like a 3rd O2 sensor, SAI, and a catalytic radiator with a special electrical connector that allows the ECM to know that the correct radiator is installed. Your car might be one with the extra emissions stuff.

You can call a dealer and give them your car's VIN so they can give you the correct part # you need.


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## rodH (Aug 23, 2002)

Audi_Mechanic said:


> There's a small connector that plugs into the side of one the pipes for radiator hoses.
> 
> Who ordered the replacement pump, you or the shop?


After hours of searching this is the exact issue I found. Notice the pics in this thread have one version with the small wire harness in the inlet tube while the other version doesn't have it. I went by the part number ECS website that said it worked on my model year, but I guess there are some variances. 

http://www.golfmk6.com/forums/showpost.php?p=1592406&postcount=512


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## rodH (Aug 23, 2002)

rodH said:


> After hours of searching this is the exact issue I found. Notice the pics in this thread have one version with the small wire harness in the inlet tube while the other version doesn't have it. I went by the part number ECS website that said it worked on my model year, but I guess there are some variances.
> 
> http://www.golfmk6.com/forums/showpost.php?p=1592406&postcount=512


Complete thread:

http://www.golfmk6.com/forums/showthread.php?t=4872&page=26


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## Evo V (Dec 29, 2010)

rodH said:


> Complete thread:
> 
> http://www.golfmk6.com/forums/showthread.php?t=4872&page=26


It looks like you have CBFA engine and you ordered a pump for CCTA.


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## rodH (Aug 23, 2002)

Evo V said:


> It looks like you have CBFA engine and you ordered a pump for CCTA.


Looks like it. This is so typical of my luck. Just enough info to get myself in trouble. Put the new water pump on and still had a leak, so ended up getting a new top hose, and sure enough that fixed it (like he originally thought). (So typical of a German company to have a small rubber seal fail and instead of just buying a cheap radiator hose and clamping it on with a metal hose clamp you have to use some stupid flimsy plastic connector that ONLY comes with the complete hose, and ends up costing $120). Then I have the problem with the wrong water pump without the electric plug, but the water pump is already in the car and working, but it gives a CEL. So for now, he took off that plug from the original water pump and plugs it in and just zip tied it so it won't rattle around. Really serves no function other than to not give me a CEL. He says to just watch the temp and for a CEL and if it keeps working, it should be fine. I guess some of them use an electronically controlled piece and some are more of a passive type, perhaps based on pressure or temp. 

Bummer I bought the wrong part. I guess that's what I get for not going to a dealer and paying $1000 for this repair. I assumed that ECS would have actually had the correct info on their site, but it doesn't differentiate base on engine code. If it eventually has a problem the other option is to try and switch that whole bottom tube with the plug on the old one and install it on the new one and hope everything fits properly, if that doesn't work, put old pump back on. But that's just more labor and money. For now it is working great.


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