Is your 996 Coolant leaking? Could be your coolant expansion tank.
A customer called a few days ago saying his 996 Carrera had a coolant leak, asking if we could fix it. We focus on performance upgrades here, but he was hesitant to drive the distance to his dealer and since we are the closest shop, we decided to make an exception.
Coolant is a pretty nasty substance and this is a particularly messy job.
The car was a stock '01 Carrera with about 66,000 miles on the odometer. The car was not overheating or throwing lights, but would leave a small puddle of "something" after a long drive.
Once on the lift, it was clear there was something leaking right above the driver's side exhaust.
Looking inside the engine compartment, coolant appeared to be leaking from the lower half of the expansion tank. I removed the cap up top, and drained the coolant (using 5mm hex to remove the drain plug).
And while here, it's a good idea to change the thermostat, so I removed the four bolts holding the thermostat housing. To make these more accessible, it's necessary to remove the 3x10mm bolts holding the smaller hard line in place.
The thermostat's a bit tricky to remove from the housing without the proper tools, so I had James work his magic to remove it. :) I cleaned the surfaces of both sides, and replaced the gasket to reinstall in the housing and plug.
The culprit, seen from above, requires removal of the intake and air pump.
The tank attaches to a few hoses, the coolant level sensor, and a zip-tie. Once these are removed, it still has to slide out of its corner, which proved to be the most difficult part of the replacement.
I also had to disconnect two fuel lines, and lower the engine a couple inches in order to remove the tank.
I also replaced the coolant level sensor, because it was brittle and worn.
Just 8 years and ~60k miles ago, that yellow tank probably looked just the same! Next time you notice a small puddle behind a 996, 997, Boxster or Cayman, follow the leak up and you'll probably see something similar to this. But don't panic: it can be fixed.