2006 Audi A3 Coolant Leak only on Long Trips

  • 2006 AUDI A3
  • 4 CYL
  • 2WD
  • 41,000 MILES
I'm having major coolant leaks on long trips (4+ hours). I drive boston<->DC frequently in the summertime, and if I fill coolant to max when departing, after 4-6 hours it will be low enough that the "Low Coolant" alarm flashes and I have to stop and refill.

1. I use 50/50 water and the suggested Audi's pink coolant, got it from autozone

2. This does NOT happen on trips shorter than 4 hours. All winter long, I only filled the coolant once, while putting on ~4000 miles. It doesn't leak in my driveway.

3. The engine never overheats. The needle consistently stays half way between C and H.

4. When I open the radiator cap, barely any pressure is released. It sounds more like a cat or dog passing gas than the loud hiss that I'm accustomed to with other cars.

I've been looking / touching looking for weak or leaky connections but haven't been able to find anything yet. Anyone who works on Audis will know how congested it is under the hood.

What should I be looking for? Will a mechanic have some fancy tests he can run on this guy? I love my car and want to keep it well maintained!

Rajat Banerjee
Do you
have the same problem?
Wednesday, June 2nd, 2010 AT 10:29 AM

1 Reply

The heat and extended drive time will build up alot more constant pressure in the cooling system.A shop can pressure test the system to see if it holds. They can also do a chemical test to be sure the head gaskets are good, just to be sure.A good visual inspection should show a tell-tale stain or something where the coolant is escaping. May even be the water pump but have a shop familiar with Audis take a look at it
Was this
Thursday, June 3rd, 2010 AT 4:11 PM

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