Slow coolant leak only when cold

[VChristian]

My 99.5 is running with the system unpressurized, and has been for 7 years. It is far easier to do than to keep replacing the o-ring that leaks on the cross pipe. This past weekend it drained the overflow bottle. The leak happens at night when it is cool, and not during the day.

The leak appears as the subframe dripping coolant. I cannot find a leaking hose or gasket.

This morning it was again leaking, and I found that there is a metal line which comes off the overflow bottle, and runs along the subframe. That is likely where the leak is.

Anyone else have something similar? I haven't looked at what is involved replacing that line, so if anyone has done it, your words would be appreciated.

 

[hughesjasonk]

if you are running VW coolant... have you ran a UV light around to see what you can find? Also have you pressurized the system to see where it's leaking out of. You'll see it. lastly, how sure are you that you don't have a headgasket leak?

 

[VChristian]

Pretty certain on head gasket leak.

I can use the UV, but I can't see where it is happening, just the fluid dripping off the subframe.

I will try looking tonight.

 

[hughesjasonk]

Pretty certain on head gasket leak.

I can use the UV, but I can't see where it is happening, just the fluid dripping off the subframe.

I will try looking tonight.

My guess is that it's coming out of the reservoir.

Sent from my SM-G930V using Tapatalk

 

[VChristian]

No UV staining on block. Staining on subframe. Ran out of time (doing ALH TB on another car and heavy rain started).

 

[hughesjasonk]

I am still inclined to think that it's coming out of the reservoir. I'm up by A Bay/Clayton if you want to stop by

 

[Legal Diesel]

I just had to have the heater core fixed on my Beetle. My symptom was fluid leaking from under the passenger door area of the car. I thought it was a busted brake line, but it turned out to be coolant.