Tillycat1

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

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!!😿