Coolant leak no signs with pressure test

[paul_james09]

So I’ve got a slow coolant leak. Maybe topping up the reservoir an inch or so every 100 miles. Only seems to leak on longer journeys.
Can’t see any signs of leakage no puddles or wet patches nor any pink corroded areas. Pressure test seems to hold pressure. No sign of coolant in oil, exhaust smell in coolant tank or white smoke from exhaust.

What areas should I check next? What’s all the possible areas that coolant could leak internally?

Car is a3 8p 2.0 170 TDI CFGB engine

Many thanks in advance

 

[richkeane1]

So I’ve got a slow coolant leak. Maybe topping up the reservoir an inch or so every 100 miles. Only seems to leak on longer journeys.
Can’t see any signs of leakage no puddles or wet patches nor any pink corroded areas. Pressure test seems to hold pressure. No sign of coolant in oil, exhaust smell in coolant tank or white smoke from exhaust.

What areas should I check next? What’s all the possible areas that coolant could leak internally?

Car is a3 8p 2.0 170 TDI CFGB engine

Many thanks in advance

I’m having the exact problem. It was leaking on longer journeys but left it recently for a week and it left it bone dry. Pressure test held and no weak areas. I am mystified!
Any ideas?

 

[Scotty]

My B6 S4 had this. They couldn't find any issue during the warranty period. After that though they found porosity in the V8's engine block! They wanted me to put £5k into it with the dealer and Audi UK covering the other £5k.

I px'ed it despite them saying it's wouldn't get worse.