Audi A3 2.0TDI Sport- Loosing Coolant on long journeys.

[Tillycat1]

Engine is fine when using as local runaround, coolant expansion tank never looses coolant.

On long journeys approximately 1 cup full of coolant is lost & specs of coolant are evident around expansion tank area. Temperature gauge on dash never increases above 90c, so no temperature related issues.

Had this issue now for 6+ months. Local garage have flushed through heater matrix & coolant pipes, etc connected. Last week coolant header support pump & coolant expansion tank replaced. Trip taken to Doncaster this weekend, approx 80 miles at average motorway speed, checked coolant approx 1 hour after arrival to find coolant reduced in expansion tank & specs of coolant around expansion tank area. Mechanic has checked for possible issues with head gasket & say no issues.

ANY Ideas most welcome as I'm tearing my hair out, what I have left!!😿

 

[Stevey Y]

1 hour ago, Tillycat1 said:

Engine is fine when using as local runaround, coolant expansion tank never looses coolant.

On long journeys approximately 1 cup full of coolant is lost & specs of coolant are evident around expansion tank area. Temperature gauge on dash never increases above 90c, so no temperature related issues.

Had this issue now for 6+ months. Local garage have flushed through heater matrix & coolant pipes, etc connected. Last week coolant header support pump & coolant expansion tank replaced. Trip taken to Doncaster this weekend, approx 80 miles at average motorway speed, checked coolant approx 1 hour after arrival to find coolant reduced in expansion tank & specs of coolant around expansion tank area. Mechanic has checked for possible issues with head gasket & say no issues.

ANY Ideas most welcome as I'm tearing my hair out, what I have left!!😿

 

Hi when they fitted the new expansion chamber did it have a new cap?, my daughters Q3 had the same problem which turned out to be the cap so we replaced it and its all happy days.

Steve.

[Tillycat1]

17 hours ago, Stevey Y said:

Hi when they fitted the new expansion chamber did it have a new cap?, my daughters Q3 had the same problem which turned out to be the cap so we replaced it and its all happy days.

Steve.

Hi Seve,

yes cap was also replaced, so at a loss to what it could be.

[Stevey Y]

58 minutes ago, Tillycat1 said:

Hi Seve,

yes cap was also replaced, so at a loss to what it could be.

Hi I was told some of the aftermarket caps supplied with new reservoirs are not that good which would explain the persistent problem you have depending where they sourced the unit I paid £36 for an OEM unit, the only other thing I found was that an excessively rich mix of antifreeze causes them to boil out what they don't need via the venting on the cap, you seem to have covered just about everything other than that and it definitely isn't the head gasket as that would chuck all the coolant out even around town.

Steve.