Engine Sputtering After Rain? A Guide to Drying Water From Coil Wells | MyMechanic
Your car was running perfectly, but after a heavy downpour or a trip to the car wash, the engine is suddenly shaking and misfiring. This common issue is often caused by water ingress—water that has found its way into the deep wells where your spark plugs and ignition coils reside.
For Singaporean drivers in Malaysia, where sudden storms are a fact of life, knowing how to deal with this is a valuable skill. This guide explains how to safely dry out the coil wells and get your engine running smoothly again. And as always, MyMechanic is on call for professional assistance.
Why Water Causes Misfires
The ignition coil needs to deliver a very high voltage spark to the spark plug. Electricity and water do not mix. When water pools in the spark plug well, it creates a path of least resistance for the electricity to escape, shorting it out against the cylinder head instead of jumping the gap at the spark plug tip. The result is a cylinder that doesn't fire, causing a rough, shaking engine.
This problem is often caused by clogged cowl drains at the base of the windshield, which allows rainwater to overflow onto the engine.
The Dry-Out Procedure: A Step-by-Step Guide
This procedure requires basic tools and patience. The engine should be OFF while you work.
Tools You'll Need:
A socket or wrench to remove the ignition coil bolts.
Compressed air in a can (ideal) OR a long, thin rod (like a screwdriver) and a lint-free cloth.
Dielectric grease (highly recommended for prevention).
The Drying Process:
1. Identify the Misfiring Cylinder: If you have a code reader, it will point you to the exact cylinder. If not, you may have to check all of them. Start with the ones most exposed to potential water runoff.
2. Remove the Ignition Coil: Unplug the electrical connector and remove the bolt holding the coil in place. Gently pull the coil straight up and out of the well.
3. Inspect for Water: Look down into the deep well. You will likely see a pool of water sitting around the top of the spark plug. The coil boot will also be wet.
4. Remove the Water: - Ideal Method (Compressed Air): Use the straw attachment on your can of compressed air to blow all the water out of the well. It will evaporate quickly. This is the most effective method. - Alternative Method (Cloth): Wrap a small piece of a lint-free cloth around the end of a long screwdriver. Insert it into the well to soak up the water. You will need to repeat this many times with dry sections of the cloth until the well is completely dry.
5. Dry the Coil: Thoroughly wipe the rubber boot of the ignition coil until it is completely dry, both inside and out.
6. Apply Dielectric Grease (Prevention): Apply a pea-sized amount of dielectric grease to the inside rim of the coil boot. When you reinstall the coil, this will create a waterproof seal.
7. Reinstall and Test: Place the coil back into the well, secure the bolt, and reconnect the electrical plug. Start the engine. The misfire should be gone.
Water Woes in Malaysia? MyMechanic Provides a Dry Solution.
Don't let a little rain ruin your drive. If you're a Singaporean driver facing a misfire after a storm, MyMechanic can help. Our technicians can quickly diagnose the issue, dry out the components, and take preventative measures to ensure it doesn't happen again.
A misfire caused by water ingress is a perfect example of a simple problem causing major symptoms. The dry-out procedure is straightforward and highly effective. For Singaporean drivers in Malaysia, understanding this process can turn a moment of panic into a manageable situation. And for a truly hassle-free solution, a call to MyMechanic ensures the job is done quickly, correctly, and with preventative measures to keep you driving smoothly, rain or shine.
