A6 / S6 (C5 Platform) Discussion Discussion forum for the C5 Audi A6 and S6 produced from 1998-2004

HELP -- massive coolant leak - back of the engine

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Old Jun 1, 2026 | 08:36 PM
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soundquest's Avatar
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Default HELP -- massive coolant leak - back of the engine

1999 A6 AWD 2.8L Base. Catastrophic heater hose breakage (can't tell if heater inlet hose or return hose) at the back of the engine down below the throttle body. Flange plastic connector snapped with the plastic barb still inside the hose with the AUDI clamp ring on the end of the hose. I am specifically looking for a good DIY write-up on this repair and also for the part numbers both for the return and the supply hoses so I can knock both of them out at the same time (assuming they are in the same vicinity). Thanks in advance.
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Old Yesterday | 06:12 AM
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soundquest's Avatar
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BUMP. Anyone? 1999 AHA engine -- heater hose. Back of the engine. Do they sell the flanges separately since I don't have to buy/install the entire hose? I have searched high and low -- for such a common problem, there is very little information available.
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Old Yesterday | 09:12 AM
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Default Check another forum

Sorry to hear that. I am not sure re question, but suggest finding the forum for your car. This is for the C5 platforms.


Originally Posted by soundquest
BUMP. Anyone? 1999 AHA engine -- heater hose. Back of the engine. Do they sell the flanges separately since I don't have to buy/install the entire hose? I have searched high and low -- for such a common problem, there is very little information available.
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Old Yesterday | 12:09 PM
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Sorry, this maybe the closest forum here. Apologies. If it is like an A4 I had, there is a plastic connector at the back of engine that could break or the o ring leaks. Might need a mirror to check it out. A temp sensor was also part of that connection on the A4.
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