doug7751

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

jpk

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.

doug7751

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

deilenberger

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.

doug7751

thanks Don, I will check that