Recently (2022) we have seen a spate of 964 fuel line failures.  We frst saw this on a 43K mile 964 motor just after installation, and, thankfully, before it starteD.

These fuel lines fail in two ways;

  1. Embrittlement – heat from the engine hardens fuel lines.  Vibrations cause cracking, and failure ensures, usually with a clean break.  This is one of the reasons all electronically managed Porsche engines have a fuel pump relay controlled by the DME. As soon as the engine stops spinning the DME turns off the fuel pump.  That being said, a even minor leak on a hot engine could cause a catastrophic engine fire.
  2. Shrinkage – n addition to hardening, the rubber n the 964 lines tends to shrink. this shrinkage in cross section allows the crimped furrels at the fittings to loosen and leak or slip free.

The solution is to replace the lines.  Factory lines are available or we can supply the four lines on op of the engine.

Alternatively, 993 lines can be fitted however this requires a replacement 993 fuel regulator, additional lines to and from the engine and…well…that’s expensive as the line includes the fuel rails.  The 993 system is much less complicated and is a direct replacement but, as of 2022, lists for $1243 plus $160 for the regulator and neither is available from aftermarket manufacturers.

We have developed direct 964 replacement fuel lines with Aeroquip stainless steel braided lines and direct fit metric fuel lines. We also make a simplified version with adjustable fuel pressure regulator and can integrate conversion lines into either model.