Coolant leak only when engine is cold?

[majorpowell]

Update: pics here https://imgur.com/a/D4i4Czt

I am having trouble with a coolant leak in my 2008 A4 2.0T Quattro with 165k miles. I recently replaced the coolant flange and sensor last month due to a leak, but now I have a leak at the front of the engine, slightly to the passenger side. Unfortunately, I cannot locate the source of the leak as it is difficult for me to see due to an old injury causing back pain. However, I have noticed that the leak only occurs when the engine is cold. When I drive the car, there is no noticeable loss of coolant, and I do not see any puddles or a low reservoir. But when the car sits for a few hours or overnight, it leaks a small drip that eventually leads to a visible puddle, and the reservoir becomes nearly empty after a few days of sitting.

Before attempting to replace the water pump and timing belt, is there any other component in the area that I should check that could be causing the leak only when the engine is cold?

[CrickiKaze]

Coolant line(s) to the turbo.

[zimflux]

I am having trouble with a coolant leak in my 2008 A4 2.0T Quattro with 165k miles. I recently replaced the coolant flange and sensor last month due to a leak, but now I have a leak at the front of the engine, slightly to the passenger side. Unfortunately, I cannot locate the source of the leak as it is difficult for me to see due to an old injury causing back pain. However, I have noticed that the leak only occurs when the engine is cold. When I drive the car, there is no noticeable loss of coolant, and I do not see any puddles or a low reservoir. But when the car sits for a few hours or overnight, it leaks a small drip that eventually leads to a visible puddle, and the reservoir becomes nearly empty after a few days of sitting.

Before attempting to replace the water pump and timing belt, is there any other component in the area that I should check that could be causing the leak only when the engine is cold?

Go to your local flaps and rent a coolant pressure tester kit. Pump up to 15 psi and see what you find.

Front of the engine on the passenger side would be a radiator and turbo coolant lines.

[Theiceman]

are you sure it isn't a headlight washer leaking ??

[majorpowell]

Here are some pics. I’m not sure if this is water pump or the turbo coolant line as suggested.

https://imgur.com/a/D4i4Czt
(Is there a way to post these inline?)

[CrickiKaze]

That could very well be the water pump.

[zimflux]

Here are some pics. I’m not sure if this is water pump or the turbo coolant line as suggested.

https://imgur.com/a/D4i4Czt
(Is there a way to post these inline?)

What did you find when you pressurized the cooling system?

[majorpowell]

I’m doing that this weekend. I’ll keep you posted. Had to wait for a day off work.

[Theiceman]

that's right under the sump. that's the water pump.

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