04 Mar Porsche Cayman Coolant Leak
The Porsche 987 Cayman was modeled off the Boxster and debuted in 2005 with great acclaim. The more ridged baby Porsche was a hit, but even a well-respected vehicle is not immune to mechanical issues, in this case, the notorious cayman coolant leak.
Unlike past Porsche models that simply used oil and airflow to cool engine temperatures, the Cayman uses a water method of cooling. The coolant absorbs the heat while passing through tunnels controlled by a water pump. Then it is pumped through the radiator, and cooled back down by the air passing over it. If this process malfunctions a leak can develop and without ample coolant, the engine can overheat, causing serious engine damage. However, the coolant level indicator light should illuminate as the engine temperature starts to climb. Other warning signs of a coolant leak include liquid spots, white smoke, and a sweet scent.
This particular Porsche Cayman that came in for service, had a low coolant warning light come on. The customer did not notice the leak on the ground, but as you can see in the pictures it was fairly significant. We took the plastic under panels off and quickly determined that it was coming from the coolant pipe assembly. (Porsche Coolant Pipe Assembly – Engine to Supply Hose – 98710650804 -)
To the untrained eye, the cayman coolant leak might seem like just the gasket for the water pipe, but the root cause of the blow-out was the plastic supply pipe itself. The gasket lies in a channel that surrounds the full perimeter of the assembly. The coolant pipe is constructed from composite plastic and unfortunately, time and heat had caused a section of the inner lip to disintegrate. The full coolant pressure could now push past the gasket and leak out of the system causing the light to come on.
The job may appear straightforward because the pipe can be seen easily with the shields removed. The screws however are not easy to access, and the pipe will not come all the way out without manipulation of the engine by removing a mount and lowering. Also, several brackets and at least the oil pressure relief valve need to be removed in order to have a clear shot at taking off the coolant water pipe.
Extra care must be taken when refilling a water-cooled Porsche’s coolant system. Due to the long distances coolant is routed, the air is easily trapped in passages. So a vacuum filling method ensures that there are no trapped air pockets after the repair is completed.
Leaking coolant is no small matter, and, as we’ve already said, it could lead to a fatally damaged engine. If you’re mechanically competent, this job is one you could tackle, but the best way to ensure a problem-free repair is to have an independent mechanic shop like Fluid MotorUnion take a look at your vehicle and offer professional advice.