Query CD coolant change
 

Does the coolant in a 958 diesel really last for ever as Porsche claims, or should it be changed from time to time?

There's typically an excuse to replace it somewhere along the way, like if the waterpump or one of the hoses needs to be replaced. 100,000 miles shouldn't be any problem.

mine has done 137k miles, the coolant looks ok but I wonder whether it should be changed?

There are test devices that can show you the protection temperature of your coolant (in case someone diluted it down with plain water when topping up) and if it has turned acidic. If it's neutral pH and still protects to a temperature lower than the vehicle will ever see, there isn't a lot of reason to change it. Coolant doesn't really wear out - it can get contaminated or diluted or acidic - if any of those happen it's time to consider changing it.

thanks Don, I will check that