Installing the Bolec WL601 Radiator Level Alarm might sound technical,
but it’s actually a fun and straightforward project—perfect for anyone who loves DIY,
tinkering under the bonnet, or spending time learning how things work.

Whether you’re a student, first-time car owner, or someone who enjoys weekend projects with family,
this guide will walk you through every step to install the WL601 safely and confidently.

What You’ll Need

• Bolec WL601 Radiator Level Alarm module
• WL601P radiator probe (included with the kit)
• Small drill with a 9.5 mm bit (for the probe hole)
• Basic tools: screwdriver, wire stripper, pliers, zip ties
• Electrical tape or heat-shrink tubing
• Optional: your dad, a warm afternoon, and some Christmas music 🎶

Safety First

Before you start, make sure your engine is completely cool. Never open the radiator cap while it’s hot — pressure can cause hot coolant to spray out. Safety glasses are a good idea too.

Step-by-Step Installation

Step 1. Find the Right Spot for the Probe

Look for a flat area on the side or top of your radiator tank — plastic tanks are fine. The probe should sit about 10–15 mm above the radiator core (the part with all the fins).

Mark the spot with a pen.

Step 2. Drill the Hole

Using your 9.5 mm drill bit, make a clean hole at your mark. Wipe away any plastic shavings. It helps to have your dad steady the drill or hold a flashlight while you work.

Step 3. Insert the Probe

Push the probe gently into the hole until the rubber seal sits snugly. It should feel firm but not forced. No need for glue or sealant — the rubber ring keeps it watertight.

Step 4. Mount the WL601 Module

Choose a dry place near the fuse panel or firewall. Use screws or double-sided tape to mount the module securely. Keep it away from extreme heat and moving parts.

Step 5. Wire It Up

• Red: 12 V or 24 V ignition power (connect to a wire that’s live when the key is on)
• Black: Ground
• White: Probe connection
• Blue: Alarm output (connect to light or buzzer)

Always add a small inline fuse (1 A–2 A) on the power wire for protection.

Step 6. Test It

Turn the ignition ON. The alarm should stay quiet when coolant touches the probe. Now remove the probe from water (or unplug it) — the alarm should activate after about 7 seconds.

If that works, you’re done! You just installed a real-world safety system — nice job! 👏

Tips for a Smooth Install

• If you’re unsure about drilling, ask a mechanic or a parent to help.
• Keep wires neat and secure with zip ties.
• Test the alarm once a month by briefly unplugging the probe.
• Label your wires — future you will thank you!

Why It’s Worth Doing

Coolant loss can happen anytime — a small leak, loose clamp, or a split hose. Many engines don’t show any warning until it’s too late. The WL601 gives you an early alert, often saving hundreds or even thousands of dollars in repairs.

And beyond the technical benefit, doing it yourself teaches practical skills — wiring, safety, attention to detail — things that school rarely covers. Plus, it’s a great bonding activity. You’ll always remember the day you and your dad installed an alarm that protects your car.

Bolec Electronics – proudly Australian-made, helping keep engines safe since 1983.