Coolant change

[Finance_Analyst]

When is the optimal time to do a full coolant / radiator flush? I always use to do it every 2 years but my last service it wasn't looked at (they did say it was 48%, of which 50% is full).

Worse thing is the risk of overheating especially with summer round the corner - although as the car is 2.5 years old , doubt it would happen (dodgy VW reliability not withstanding)

[Diesel_vert]

The optimal time to change something is when it needs changing, haha.

It's possible to use a calibrated refractometer to determine the coolant's concentration level. The dealer should have one that's specifically calibrated for G12 and G13 coolant.

Volkswagen use a lobrid coolant (OAT with small amounts of silicate, similar in principle to hybrid OAT) which has a very slow additive depletion rate, and has no specified replacement interval.

Unless specified, 5 years or 250 000 km seem to be figures bandied about in regards to such long-life coolant.