Welcome to the continuation of our new DIY series, where CorvSport scours the internet for the best DIY guides. With CorvSport your digital encyclopedia, we bring you the best guides and resources from the vast Corvette community. This series will also give hobbyists considering DIY projects the clarity they need to know when to hire a professional.
Almost every generation has at least one component that an inherent problem prompts enthusiasts to actively replace. You will hear something similar to the following:If you do not replace it immediately, it may malfunction and be damaged in the worst case scenario.For example, in the case of the C5, that component is the harmonic balancer, and we've published a guide to its DIY fix here. For the fourth-generation Corvette, that component is Opti-Spark. And today's guide also includes an “in-between” component: the water pump.
CorvSport Complexity Guide
- Difficulty: 7 (10 most difficult)
- Patience required: 9
- Level of specialized tools required: Five
- Is a helper recommended? No
Today's guide was brought to you by Corvette Forum member “LT1*C4” and is the best and most comprehensive guide we could find on the internet. To supplement this guide, we have also included a highly recommended YouTube video. This hand-picked C4 Opti-Spark and water pump replacement is fully credited to “LT1*C4” and provided to the CorvSport community in unedited form. In these instructions, you'll see that LT1*C4 has taken the time to include detailed instructions with photos.
How to replace the Opti-Spark and water pump on your C4
Step 1: Remove the battery
Step 2: Drain the engine coolant
Step 3: Unplug the IAT sensor
Step 4: Access the throttle body and water pump
Step 5: Remove the coil wire.
Step 6: Remove the passenger side hose
Step 7: Unplug the IAC valve
Step 8: Remove the TPS sensor
Step 9: Remove the vacuum line.
Step 10: Remove coolant hoses
Step 11: Remove throttle cable
Step 12: Remove the throttle body
Step 13: Prepare for water pump removal
Step 14: Disconnect the ECT sensor
Step 15: Delete the connection to Opti-Spark
Step 16: Remove the serpentine belt
Step 17: Remove the water pump
Step 18: Remove the plug wire.
Step 19: Remove crank pulley
Step 20: You are now halfway done.cleaning time
Step 21: Check the water pump drain hole (if not replacing with a new one)
Step 22: Prepare the electric water pump for installation
Step 23: Prepare and install Opti-Spark
Step 24: Reinstall the pulley
Step 25: Prepare and install Opti-Spark
Step 26: Reinstall the plug wires
Step 27: Prepare and install the water pump
Step 28: Reinstall the six cover bolts.
Step 29: Bypass throttle body coolant (optional)
Step 30: Refill the cooling system
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