Does your Ford Focus misfire and stutter after wet weather? If so the problem could be easier to isolate and fix than imagined. Kim Henson tells more…
This true story should really be under the ‘Steve’s Tips’ heading, rather than ‘Kim’s Tips’, and results from a conversation with my friend ‘Steve on the Isle of Wight’. He told me that his family’s petrol-powered Ford Focus was running roughly/misfiring every time it rained.
He discovered that rainwater was collecting around the spark plugs, located within wells in the cylinder head, and adversely affecting the ignition system’s high tension circuitry.
Soaking up the water using a soft cloth would cure the trouble – until it rained again.
Steve advised me that it was proving difficult to discover the point or points where water was entering the engine compartment, in order to fix the leak(s).
In order to progress his diagnostic work, he decided to lay an old, folded towel across the top of the engine and leave it in place (when the engine was cold and NOT starting it of course) until after it rained. (Steve’s copyright photo, above, shows the towel in place to help identify the source of the rainwater leak).
When it did rain again, it was found that the towel was predominantly damp on the driver’s side of the vehicle. Closer investigation proved that the culprit was the screen washer nozzle, mounted in the bonnet just above this area, and a slightly loose fit, allowing the rain to drip onto the engine in exactly the worst possible place.
This was soon sorted/re-sealed and the engine now stays dry and runs well again.
Sometimes it can be difficult to trace a water leak into a car since gravity and capillary action can result in pooling of the water some distance from the entry point into the vehicle. However it is especially important to check (frequently) carpets and floors for moisture, and to fix any rainwater leaks discovered. This helps to preserve the structure of the car and in the case of modern vehicles can help to avoid electrical breakdown (essential electrical units/assemblies are often installed beneath carpets and close to bulkheads etc, where moisture ingress can wreak havoc).
With many modern cars (remarkably including some very recent models!) water can find its way into electrical units/cables/connections, including the main Electronic Control Unit (ECU) and cause short circuits. In some cases, apart from resulting in the car running badly, or failing to start at all, such moisture ingress can write off an ECU (etc.), and even a tiny water leak can result in long-term damage, if left to its own devices. This can be hugely expensive to fix…
As a preventive measure, the application of waterproof silicone grease around electrical connections/units can help to keep things operational, but if a water leak is present, finding and fixing the leak itself is always vital as a first step!
I should add that many modern vans have frontal bodywork design that tends to channel water onto the top of the engine. This is especially bad news if the engine’s top cover is damaged or missing, in which case it would be wise to obtain a replacement or mend the original cover, as soon as possible. Depending on the vehicle, it may also be possible to rig up an additional cover/water deflector, to help direct the water away from the engine and electrical components/wiring. Make sure that the cover is safely clear of all moving parts.
VERDICT
Don’t ignore water leaks into the engine bay or vehicle interior – fixing them early will avoid inconvenience, financial heartache and frustration galore!
My thanks to ‘Steve on the Isle of Wight’ for his story about his family’s leaking Ford Focus.