The original OEM, stock vacuum hoses are black rubber.  They're usually not a problem with vacuum hoses unless they have been removed before.  One trouble area with vacuum hoses is the area above and around the turbocharger.  This is due to the immense heat the turbocharger emits.  Heat is what causes rubber vacuum hoses to harden.  Once these vacuum hoses harden, they are very prone to breaking or leaking.

A very popular mod is to replace the rubber vacuum hoses with colorful silicon hoses.  One advantage of silicon is that it keeps its flexibility, even with high heat, and it's self-lubricating.  Although silicon is very resistant to heat, it can tolerate only occasional exposure to petroleum products, such as gasoline or oil - do not use silicon where constant exposure to either gasoline or oil is possible.

To replace all of the vacuum hoses under the engine, you need approximately:
  • 30 feet of 4mm (~3/16")
  • 10 feet of 6mm (~1/4")
  • 2 feet of 10mm (~3/8") - upper intake manifold to brake booster

  • These estimates do not include the vacuum lines to and from the charcoal canister, various coolant lines, or fluid lines from the windshield wiper spray motor to the spray nozzles on the hood.  Add additional amounts of hose if you're planning to replace these hoses as well.  Silicon hose can handle being used as a low-pressure coolant hose.

    For the most part, the silicon hose ends fit snugly and need no clamps to keep them secure.  If you want to make sure they don't pop-off, you can add wire ties to these ends.

    You can get silicon vacuum hoses from your local import performance shop or these online vendors:
  • Hose Techniques
  • Baker Precision

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