Porsche 911 996 Series Cracked Cylinder Heads

Porsche 911 996

The Porsche 911 series has been one of the most successful two-door sports cars in automotive history. Variations on this design have brought home multiple victories at racing events such as the Targa Florio, Daytona, and the 24 Hours of Le Mans. The 996 series—made available in showrooms between 1998 and 2004—was the first 911 to feature a water-cooled engine instead of the standard air-cooled one. One of the more usual problems associated with the 996 are cracked cylinder heads.

The cracking of the cylinder heads is usually due to a too-high torsional level on the bolts on the cylinder faces. This causes the engine to run too fast, and the added stress and wear causes the heads to crack. With a cracked head, the most obvious sign are bubbles forming on the radiator. These bubbles come from the exhaust that is supposed to be expulsed from the cylinder during the second down stroke of the piston, but, due to the crack, winds up leaking into the cooling system. Conversely, you might experience a situation wherein the coolant floods the cylinder while the car is off, with the leak again occurring from the cracked cylinder head.

Usually, this problem will result in the short term with a misfiring cylinder. If left to worsen, you might find yourself with water flowing from your tailpipe, a seized engine, and a horrifyingly expensive fix on your hands. When a cracked head is discovered, you might be able to get away with a simple flush of the cooling lines, but if the issue has persisted for some time you might find yourself needing to replace several systems as well as the cylinder.

Rather than run the risk of destroying your 996s engine, take your car to a nearby Porsche repair mechanic who can run a complete diagnostic of your vehicle and tell you A) whether or not you have a cracked cylinder head, and B) what you need to do about it now.

Search for a local, independent Porsche repair shop with Porsche mechanics that have dealer-level expertise at a fraction of the expense.