Leaking coolant at the firewall connection

RedTDIowner

Veteran Member
Joined
Aug 24, 2004
Location
Crestwood KY
TDI
2014 Audi A6 3.0 TDI
I had someone do an EGR delete on my ALH a few years ago and have now noticed that the coolant hose that goes from the side of the head to the fire wall has a small leak. Its nothing major but if you put your hand up around where the hose connects to the firewall you will feel that its wet and has a slight leak. I add coolant to the reservoir every few weeks but want to address the issue. I have looked at it and it appears to be some type of quick disconnect at the end of that hose which connects to the firewall. How do you disconnect it? Is it easy to replace?
 

Enabled

Veteran Member
Joined
Apr 23, 2013
Location
Houston, TX
TDI
2003 Jetta TDI Manual, BMW 328d SW
Mine did the same, they're easy to disconnect. Pull the metal snap ring outwards, and pull the quick connect elbow down.
You can buy the whole quick connect elbows, which come with new o-rings, and they will not leak. I tried to replace just the o-rings and didn't have much success.
Easy job with cold engine.
 

RedTDIowner

Veteran Member
Joined
Aug 24, 2004
Location
Crestwood KY
TDI
2014 Audi A6 3.0 TDI
Mine did the same, they're easy to disconnect. Pull the metal snap ring outwards, and pull the quick connect elbow down.
You can buy the whole quick connect elbows, which come with new o-rings, and they will not leak. I tried to replace just the o-rings and didn't have much success.
Easy job with cold engine.
Thanks for the reply. Can you please provide a link where I can buy the quick disconnect elbow??
 

RedTDIowner

Veteran Member
Joined
Aug 24, 2004
Location
Crestwood KY
TDI
2014 Audi A6 3.0 TDI
Well I did some investigating and took pictures. Its leaking where both ends of the hose connect. One leak is at the the fire wall going to the heater core and the other is on the right side of the head. It looks like the clamps are not getting the hose tight enough thus not sealing it which is allowing a small amount of coolant to leak out. Would you just replace the clamps with new ones and see if that fixes it? Or would you go ahead and replace the hose too since the hose has already seated wrong and not sealed correctly?

Since my EGR delete I have had two different hoses installed on my car which connects the coolant line from the head to the firewall. The first one I had installed went under the brake master cylinder. Over time it rubbed against another hose or line and got a hole in it. It was then replaced with one which goes next to the brake master cylinder. The link that was posted on here for the quick disconnect coupling is angled and that one will not work on my hose. I am needing the straight quick disconnect coupling and found it on ID parts.



 
Last edited:

RedTDIowner

Veteran Member
Joined
Aug 24, 2004
Location
Crestwood KY
TDI
2014 Audi A6 3.0 TDI

Enabled

Veteran Member
Joined
Apr 23, 2013
Location
Houston, TX
TDI
2003 Jetta TDI Manual, BMW 328d SW
By the looks of those pictures, you should replace the complete hose as well. That rubber will not hold together long.
 

BobnOH

not-a-mechanic
Joined
May 29, 2004
Location
central Ohio
TDI
New Beetle 2003 manual
^Yes^ It looks like in both photos it's just the hose leaking. 2nd photo looks like a hose ready to blow. Go ahead and inspect all your water hoses, if any are bulging like that, replace them.
VW hoses are high quality, but any leakage of certain substances will change the chemistry of the material.
 

RedTDIowner

Veteran Member
Joined
Aug 24, 2004
Location
Crestwood KY
TDI
2014 Audi A6 3.0 TDI
^Yes^ It looks like in both photos it's just the hose leaking. 2nd photo looks like a hose ready to blow. Go ahead and inspect all your water hoses, if any are bulging like that, replace them.
VW hoses are high quality, but any leakage of certain substances will change the chemistry of the material.
Yes after I replaced the hose I noticed how much bigger it was then the new hose. It was very swollen, which surprised me becuase I was under the impression that the coolant system on the A4 ALH TDI engine was not a high pressure system. No other hoses on my coolant system were swollen. I will post pics soon.
 

RedTDIowner

Veteran Member
Joined
Aug 24, 2004
Location
Crestwood KY
TDI
2014 Audi A6 3.0 TDI
What do you think made this hose swell up so much? You can see how much smaller the replacement hose is.



 

RedTDIowner

Veteran Member
Joined
Aug 24, 2004
Location
Crestwood KY
TDI
2014 Audi A6 3.0 TDI
What do you think made this hose swell up so much? You can see how much smaller the replacement hose is.
Dropped by and had Paramedic and his son Eric work on my car today. I showed him that swollen hose and he thinks its because my heater core might be partially clogged. It was reiterated to me how important it was to use distilled water when mixing your G13 instead of using tap water, especially since in KY the ground is full of limestone where they draw the water and therefore our tap water has a lot of lime and calcium. Doh!
 
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