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Autopapyrus · Kia Sorento 2.4 GDI G4KJ (2010)
https://autopapyrus.com/guides/kia/sorento/camshaft-replacement/
Compiled automatically from service literature and owner experience. Specs are for the typical configuration — check them against your exact car before you start.

Kia Sorento 2.4 GDI G4KJ (2010): Camshaft Replacement

The G4KJ is a chain-driven engine with variable valve timing (VVT) phasers on the camshafts. This job requires precise alignment of the timing marks and careful work on the high-pressure fuel system. Camshafts are replaced for scored lobes, pitting, noise from the top end, or after loss of oil. If you are unsure of your experience, have a shop do the work: an error in valve timing can cause the pistons and valves to collide.

Difficulty: Hard Time: 6-10 hours Steps: 18

Parts

6
№Part
01 G4KJ (2.4 GDI) camshafts: intake and exhaust, set
02 Valve cover gasket with spark plug well seals
03 Engine oil
04 Oil filter
05 Timing chain with tensioner and guidesrecommended if worn
06 GDI injector O-rings and sealsif the fuel rail is removed

Tools

10
  • Socket set and ratchet
  • torque wrench (low range 5-60 N·m (4-44 lb-ft))
  • pulley holding tool or a wrench to hold the camshaft by its hex flat
  • camshaft locking pins or timing-mark locking tools
  • fuel rail puller/adapter
  • oil drain pan
  • brush and clean rags
  • gasket sealant for mating surfaces
  • syringe or tweezers for small parts
  • marker and containers for sorting parts
There's a full repair manual for this car Every system, wiring diagrams and torque specs — not just this job. Haynes and 5 more. See manuals →

Step by step

18 steps
  1. Disconnect the battery. Park the car on a level surface; the engine must be cold. Remove the engine cover, the air duct, the air filter with its hoses, and anything else that blocks access to the valve cover.
  2. Relieve the fuel system pressure: remove the fuel pump fuse or relay, start the engine and let it stall, then crank it with the starter 2-3 times. On a GDI engine the pressure in the rail is very high, so do not loosen the high-pressure fuel lines without relieving the pressure first. Keep dirt out of any open passages.
  3. Disconnect the connectors of the ignition coils, the camshaft position sensors, the oil control valves (OCV) for the valve timing, and the wiring harnesses on the valve cover. Remove the coils and unscrew the spark plugs, taking care not to drop them into the wells. Label and photograph the routing of the harnesses and the crankcase ventilation hoses.
  4. If needed for access, remove the fuel rail with the GDI injectors, or at least disconnect the high-pressure fuel pump drive if the pump is driven by the camshaft. Remove the rail and injectors strictly according to the service procedure: the injector O-rings and Teflon seals must be replaced with new ones after removal. Plug the open ports with clean caps.
  5. Remove the valve cover: loosen the bolts evenly in several passes from the edges toward the center, and carefully separate the cover from the sealant without prying on the mating surface with a screwdriver. Clean the mating surfaces of old sealant with a degreaser.
  6. Set the engine to TDC on the compression stroke of cylinder 1 by turning the crankshaft in its normal direction of rotation with the pulley bolt. Align the marks on the camshaft sprockets and on the chain (if the chain has colored links, they must line up with the marks on the sprockets). Photograph the position of the marks, and use a marker to put reference marks on the chain and sprockets.
  7. Secure the chain so it cannot slip: tie it to the sprocket with wire or a zip tie so the chain does not fall into the engine block. If the chain falls into the crankcase, you will have to remove the front timing cover.
  8. Relieve the tension on the chain: lock the tensioner according to the service procedure. Loosen the bolts holding the sprockets/phasers to the camshafts while holding the camshafts by the hex flat on the shaft itself. Do not use the chain as a brace, as you will damage it. Remove the sprockets with the chain and carefully hang the chain out of the way.
  9. Loosen the camshaft bearing cap bolts in several passes, working from the edges toward the center, and mark each cap (order and orientation). Remove the caps and lift out the camshafts. Inspect the journals and bearing seats: any scoring, deep scratches, or discoloration from overheating means the oil passages and the cylinder head need to be checked.
  10. Check the lifters, hydraulic lash adjusters, or rocker arms (depending on the cylinder head design) for wear. If new camshafts are installed on worn lifters, the life of the new set will be cut sharply short, so replace those parts together with the camshaft whenever there are signs of pitting.
  11. Lubricate the journals and lobes of the new camshafts with assembly lube or clean engine oil. Install the camshafts in the correct positions (intake and exhaust are not interchangeable), apply oil to the bearing surfaces of the caps, and install the caps according to their marks.
  12. Tighten the bearing caps gradually, in two or three passes from the center toward the edges. The tightening torque for the cap bolts on this engine family is in a small range of about 10-15 N·m (7-11 lb-ft); check the exact value against the manufacturer's specification.
  13. Install the sprockets/phasers, aligning the marks and the chain position as they were before disassembly. Tighten the sprocket bolts while holding the camshaft by its hex flat; the torque is per the specification (much higher than for the caps, roughly 50-80 N·m (37-59 lb-ft)). Do not forget to remove the chain lock and return the tensioner to its working position.
  14. Turn the crankshaft by hand through two full revolutions in its normal direction of rotation and check again that all the marks line up at TDC. If the crankshaft turns stiffly or the marks do not line up, stop immediately and find the cause. Do not start the engine.
  15. Apply sealant to the joints as recommended by the manufacturer, and install a new valve cover gasket and new spark plug well seals. Tighten the valve cover bolts in several passes from the center toward the edges; the torque is about 8-12 N·m (6-9 lb-ft) (per the specification).
  16. Install the injectors, the rail, and the high-pressure fuel pump with new seals, following the torque values and tightening sequence in the specification. Install the spark plugs (approximately 20-30 N·m (15-22 lb-ft)) and the coils, connect the connectors and hoses, and put the pump fuse and the battery back in place.
  17. Replace the engine oil and oil filter, since the old oil is contaminated with wear particles. Before the first start, crank the engine with the starter for 10-15 seconds with the fuel injection disabled (fuel pump fuse out) so that the phasers get oil pressure.
  18. Start the engine and let it idle for 5-10 minutes, listening for unusual noises from the chain and the phasers. Check the valve cover and the fuel rail for leaks, and read any fault codes related to the valve timing and fuel injection. After 500-1000 km (300-600 miles), check the oil level and look for leaks.

Common mistakes and warnings

  • An error in the valve timing or improper tightening of the camshaft bearing caps can cause the valves to collide with the pistons and lead to expensive repairs
  • The GDI fuel system operates at very high pressure, so relieve the pressure before disconnecting any lines and keep everything clean
  • Before installing the camshafts, assess the condition of the chain, tensioner, and guides: if the mileage is high, replace them at the same time
  • Check all torque values given here as ranges against the manufacturer's specification for your engine version
  • If you have no experience with timing work, it is better to go to a repair shop