[NSW911]

Those of us who have owned one of the older 911’s will remember that when draining the oil, approximately 3 litres would remain in the lines leading up to the front oil cooler.

A similar situation applies when draining the coolant in one of our liquid cooled cars. Unless you are prepared to “go the whole hog” by spending time and money in extracting all the coolant using special tools, pumps etc, you will finish up with a not insignificant amount of fluid remaining in the system.

To my knowledge the Porsche maintenance schedule contains no specific reference to periodic coolant flushes but I have long felt that changing out the coolant every so often can certainly do no harm!

A recent engine/transmission drop from my manual 997 resulted in the removal of 16 litres of coolant drained from the approx. 32 litres contained in the system. I topped up the system with new coolant following the completion of mechanical work and although this did not amount to a complete fluid change it did result in a change from 100% “old” fluid to a mix of 50% old and new.

Months later during an oil and filter change I simply repeated the procedure by draining coolant from the engine and refilling with new fluid, diluting still further the mix of old and new coolant in favour of the new.

Like when carrying out an oil change on an older 911, I suggest this is a better way to go rather than attempting to extract every drop of fluid from the system in one attempt.

My two cents worth.