06/06/2026
Discovery 4 – Restricted Performance
The words that most Discovery 4 owners never want to see appear on the dashboard.
From experience, one of the first things that comes to mind is the dreaded cracked intake manifold, a common fault that can cause a range of performance issues. However, we never assume – diagnosis always comes first.
We started with a smoke test to check for boost and intake leaks. This quickly revealed a severely leaking Y-pipe, which was certainly contributing to the restricted performance warning. Further investigation also confirmed that the intake manifold had indeed failed.
With the faults identified, we carried out the necessary repairs and a few additional maintenance items while the vehicle was with us:
🔧 Replacement intake manifold
🔧 Replacement Y-pipe seals
🔧 Auxiliary belt
🔧 Idler pulley
🔧 Start-stop battery
🔧 Electronic handbrake switch
A thorough diagnosis and the correct repairs have this Discovery 4 back to full performance and ready for many more miles.
