Jetta L4-1781cc 1.8L SOHC (RV, PF) (1989)
If any hose clamps require replacement; only use P/N: N 900 213 01.
Step 1. Preliminary Checks
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test drive vehicle and determine engine performance
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check ignition timing point, correct if necessary
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verify that proper thermo sensor is threaded into coolant water flange
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P/N: 035 919 369M (Digifant II Golf/Jetta)
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replace with correct part if necessary
Note:
As of model year 1989, a plastic coolant flange has been installed which uses thermoswitch # 025 919 041A
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check for vacuum leaks
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repair if found
Step 2. Carbon Build-up, Diagnosis
Visually inspect the intake valves and ports for carbon build-up as follows:
Note:
Checking for carbon build-up on Golf or Jetta engines with Digifant II is time consuming, and should only be performed if a customer still experiences
performance problems after 2 or 3 consecutive cleaning attempts with Autobahn gas additive, P/N: ZVW 246 001 (20 oz. bottle)
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remove intake manifold
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set cylinder to be checked at top dead center (on compression stroke)
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using inspection mirror and flex-light, determine degree of carbon build-up on intake valves (through intake ports)
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compare your observation with chart
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reinstall intake manifold with new gasket