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Autopapyrus · Hyundai Tucson 2.0 G4GC (2008)
https://autopapyrus.com/guides/hyundai/tucson/crankcase-ventilation-system-cleaning/
Compiled automatically from service literature and owner experience. Specs are for the typical configuration — check them against your exact car before you start.

Hyundai Tucson 2.0 G4GC (2008): Crankcase Ventilation System Cleaning

On the 2.0 (G4GC) engine, crankcase gases leave through the PCV valve on the valve cover and hoses into the intake tract. Over time, oil emulsion and carbon deposits build up in them. This causes oil in the intake, leaks at seals and gaskets, increased oil consumption, and a rough idle. Cleaning comes down to flushing the valve and hoses and checking that they are not blocked.

Difficulty: Easy Time: 1-1.5 hours Steps: 11

Parts

4
№PartGenuine part no.
01 PCV valve (G4GC)if faulty (not passing air or stuck)
02 Crankcase ventilation hoses, oil-resistantas needed
03 Valve cover gasketif the cover was removed 20920-23F00
04 Engine oil (G4GC)if changing it after cleaning

Part numbers are from the manufacturer's original catalogue. Check them against your VIN before ordering.

Tools

7
  • Socket set and ratchet
  • screwdriver
  • hose clamp pliers
  • carburetor or throttle body cleaner
  • container of clean gasoline or solvent
  • rags
  • new hoses if needed
There's a full repair manual for this car Every system, wiring diagrams and torque specs — not just this job. Haynes AutoFix (online) and 2 more. See manuals →

Step by step

11 steps
  1. Shut off the engine and let it cool down. Open the hood and remove the engine cover if there is one.
  2. Find the fitting with the PCV valve on the valve cover. A hose runs from it to the intake manifold, and a second hose (fresh air) runs from the air intake or the duct behind the air filter to the valve cover.
  3. Disconnect both hoses. To do this, squeeze the spring clamps with pliers and carefully slide the hoses off. Old rubber hardens and cracks, so do not yank on it.
  4. Remove the PCV valve from the valve cover. Shake it: a good valve should click, and the moving plunger should travel freely. If it does not click or is stuck, it is better to install a new one.
  5. Clean the valve with cleaner or clean gasoline. Blow air through it or blow through it by mouth: air should pass in one direction and be blocked in the other. Do not use sharp objects inside it.
  6. Clean the hoses and metal tubes. Flush them with solvent and blow them out. If there is a thick layer of tar inside that will not wash off, or the rubber has swollen and cracked, replace the hose.
  7. Remove the air duct and inspect the throttle body and the intake tract. Remove oil residue and emulsion with throttle body cleaner and a rag. Do not push the throttle open with your finger, and do not let cleaner get into the electronics.
  8. If there is a lot of emulsion in and under the valve cover (a sign of short trips and condensation), remove the valve cover and clean it. Tighten the cover bolts in 2-3 passes from the center outward, to about 7-10 N·m (5-7 lb-ft). Check the exact value against the manufacturer's specification. Install a new gasket and check the mating surfaces.
  9. Reassemble in reverse order. Put the clamps back in their original positions and check that the hoses fit tightly and are not kinked.
  10. If the oil in the crankcase is emulsified (light colored, like "mayonnaise"), replace it together with the oil filter.
  11. Start the engine and let it idle. Check the idle speed, smoothness of operation, and the absence of air leaks (whistling). Read the OBD codes if the Check Engine light is on.

Common mistakes and warnings

  • Work only on a cold engine and do not let cleaner or dirt get into the intake tract
  • If oil is still being pushed into the air filter after cleaning and oil consumption remains high, check the compression and the condition of the piston rings and valve stem seals
  • The problem may be in the engine itself rather than in the ventilation