Isuzu 4HK1 / 6HK1 — Turbocharger and exhaust manifold installation
Repair & overhaul
For the Isuzu 4HK1 / 6HK1, from the Isuzu service manual.
Applies to: Isuzu 4HK1, Isuzu 6HK1
Before you start
- Do not over-tighten exhaust manifold to allow heat expansion.
Procedure
- Put gasket in and install exhaust manifold; tighten nuts/bolts in order (4HK1: 2 nuts/6 bolts; 6HK1: 12 nuts).
- Install gasket and turbocharger to exhaust manifold; tighten nuts.
- Tighten adapter bolts (exhaust manifold side).
- Install water feed pipe to turbocharger (4HK1 only); tighten joint bolts.
- Install pipe bracket and tighten bolts.
Tools required
- torque wrench Amazon
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
Specs & values
- Exhaust manifold: 34 N·m (25 lb ft) for 4HK1; 55 N·m (40 lb ft) for 6HK1; 34 N·m for (7) only
- Turbocharger nuts: 52 N·m (38 lb ft)
- Exhaust adapter bolts: 32.4 N·m (24 lb ft)
- Water feed pipe joint bolts: 41 N·m (30 lb ft) (4HK1)
- Water feed pipe bracket bolts: 24 N·m (17 lb ft) (4HK1)
Full service-parts list: Isuzu 4HK1 →, Isuzu 6HK1 →
Source: Isuzu service manual. Steps and values are as documented; always cross-check against the official manual and any later revisions for your exact serial number before servicing.