Installing 4/2-way valve with thermostat: VW Jetta VI / Golf V / Jetta 2.0 TDI (CFFB, CFHB, CFHC, CLCA, …)

🧭 Before you start

Seat the valve connection on a new O-ring and bolt it to the block, then refit the coolant hoses on unions A, B and D. Next come the dipstick tube, alternator, right air pipe with the G31/G42 sender connector, the front coolant pipe and the left air pipe with its wiring and vacuum hoses. Finish with the crankcase breather hose, battery carrier, battery, air filter housing and engine cover, then replenish the coolant.

Fits: VW Jetta VI (16, 2010–2018), VW Golf V / Jetta (1K, 2003–2009); platform code AJ5

Don't miss

• Use a new O-ring on the valve connection, moistened with coolant, and push it in with slight rotary motions.
• Valve securing bolts (3) go to 15 Nm with a T-bar and 10 mm socket.
• Fit the coolant pipe to valve connection (C) and hoses to unions (A), (B) and (D) before refilling.
• Refit the charge pressure/intake air temperature sender connector on the right air pipe; a missed plug sets faults straight away.
• Reconnect the vacuum hoses and crankcase breather hose before the air filter housing hides them.
• General practice: bleed the cooling system properly and recheck the level once the engine has warmed up and cooled.

Written for this job from the workshop steps below · TorqFix editorial.

🔧 Engine codes this applies to

🔩 Torque settings

Values can differ between engine variants — check the code stamped on your block.

ℹ️ Always cross-check the exact figure against your vehicle's factory manual before final tightening — a wrong torque can damage the engine. These values are extracted from workshop data and may not cover every variant or revision.

📋 Procedure

1. Moisten new O-ring (1) with coolant.
2. Insert connection (2) of 4/2-way valve with O-ring (1) into cylinder block with slight rotary motions.
3. Tighten securing bolts (3) using T-bar and 10 mm socket3185. Specified torque: 15 Nm — 15 Nm (11 lb-ft)
4. Fit coolant hoses on unions (A), (B) and (D).
5. Insert dipstick tube downwards into cylinder block.

6. Fit clip (2).
7. Screw on and tighten bolt (1). Specified torque: 10 Nm — 10 Nm (7.4 lb-ft)
8. Install alternator Starter, current supply, CCS27Removing and installing alternator.
9. Bring right air pipe into position and fit electrical connector (1) on charge pressure sender G31/intake air temperature sender G42.
10. Screw in and tighten bolts (arrows).
11. Secure hose clip (2).
12. Install coolant hose (3).
13. Fit coolant pipe to connection of 4/2-way valve (C).
14. Position front coolant pipe and secure with bolts (arrows).
15. Attach electrical connector (1) for Hall sender G40 in bracket. [Note: Disregard (2) and (3).]
16. Fit coolant hoses and secure hose clamps (1). [Note: Disregard (2), (3) and (4).]
17. Fit left air pipe and secure hose clip (3).
18. Attach electrical wiring and hoses on left air pipe.
19. Screw in and tighten bolts (2), (5) and (arrows). [Note: Disregard (1) and (4).]
20. Secure wiring harnesses (arrows) and electrical connector (1) on bracket.
21. Clip wiring harness into bracket (arrow).
22. Fit air pipe with intake union on turbocharger, swing forwards and tighten bolt (2).
23. Fit vacuum hoses on air pipe (arrows).
24. Fit hose (1) for crankcase breather on cylinder head cover.
25. Install battery carrier, screwing in and tightening securing bolts (arrows) to do so Electrical system27Removing and installing battery.
26. Install battery Electrical system27Disconnecting and reconnecting battery.
27. Install air filter housing with air mass meter and connecting pipe .
28. Fit engine cover .
29. Replenish coolant .

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