Daihatsu Hijet: KF-VET Intercooler Hose Split at Boost Clamp

Turbocharged S500P variants fitted with the KF-VET engine route compressed air from the turbocharger outlet through a charge-cooler intercooler and back to the throttle body via rubber boost hoses secured with metal spring or worm-drive clamps. The rubber hose material fatigues under repeated heat-cycling and sustained boost pressure. Stress concentration at clamp edges — particularly where a rigid clamp contacts aged rubber — leads to circumferential splits that open under boost but may seal at idle, making diagnosis difficult. A split hose causes immediate boost loss, lean mixture risk, and potential turbo overspin. Grey import vehicles with high JDM mileage are particularly susceptible as original rubber hoses may never have been replaced.

• Sudden loss of boost power under acceleration
• Audible hiss or whistle from engine bay under load
• Engine hesitation or flat spot above 2,500 rpm
• Possible lean mixture warning or check engine light
• Turbo spooling audible but power not following

With engine off, inspect all intercooler hoses and their clamp edges carefully — split hoses often only open under pressure and may appear visually intact at rest. Squeeze hoses near clamps to feel for brittleness or cracking. A smoke leak test or pressurised intake test will reveal any boost leaks that visual inspection misses. Check both the turbo outlet hose and the intercooler-to-throttle-body hose. Inspect clamp condition for corrosion or inadequate torque.

Parts involved: Turbocharger.

$150 to $420 at New Zealand independent workshop rates. That is for this job on its own, not for the car.

An estimate, in NZD, for the repair as normally carried out. What a specific car costs depends on which part has failed and what it damaged on the way — treat this as the floor for a negotiation, not a quote.

• “Have the intercooler hoses been replaced and if so when?”
• “Has the vehicle shown any boost pressure drop or flat spots under hard acceleration?”
• “Has a boost leak test been performed?”
• “What is the total mileage including JDM kilometres before NZ import?”

The failure described above is documented in published sources — owner forums, technical service bulletins, recall notices and workshop write-ups — held in our fault database. The inspection instructions and the cost estimate are KickTyres’ own interpretation of them, and it is a starting point for an inspection rather than a manufacturer statement.