In this hot summer weather, have you been hearing a jet engine sound from the front of your watercooled Porsche?
Does the sound continue even after you have shut the engine off?
If so, you may have a failed radiator fan. Due to how low Porsche’s are to the ground, and with their massively open bumper intake ducts, it is not uncommon to have a fair amount of road debris like leaves, twigs, even sizable rocks, in these ducts. What happens once enough of this debris piles up, is that the debris blocks the fresh airflow to your front radiators (most watercooled Porsche’s have 3 radiators up front; a center, a left, and a right). This in turn can cause the engine’s coolant temperature to overheat, causing the radiator fans to work much harder, often fatiguing their motors sooner than later. Once one of your side (left or right) radiator fans fail, then the engine management computer module sees that the coolant temperature is increasing beyond its engineered parameters, so the opposite side radiator fan increases to a much faster speed to try to overcompensate and cool the engine temp down; this is the jet engine sound you may hear from the front of your Porsche.
One way to prevent this from happening is to make sure you’re having your Porsche maintained on a regular interval (every 12-20k depending on model year), as one of the items on Porsche’s inspection list is to clear any blockages from the radiators and air intakes. Without blockages, your Porsche will run cooler and more efficiently, and in general be a jollier Porsche.
Happy Porsche motoring!
As always, let us know if you have any specific questions, and/or a topic suggestion for a future technical blog submission.