Why Pakistani Monsoon Flooding Is a Genuine Engine Threat
These scenes are repeated every July/August in the main cities of Pakistan. The underpasses of Lahore become filled within few minutes after every heavy rainfall. The streets of Karachi are turned into rivers. Urban streams run over on the main roads in Islamabad. For Pakistani drivers, these conditions are just a way of life, but most are unaware of how quickly and devastating the flood water can be on a car engine.
The size of the air intake for the average car engine is around 30 to 60 centimetres above the ground depending on type. This is far less than what most drivers think. Even from the inside of the car, a road that looks shallow may be up to the air intake due to the presence of standing water and/or debris that pushes water up, especially in dipped underpasses and construction areas. After the water has gone into the air intake, the damage that ensues can be catastrophic and often times irreparable.
What Happens to Your Engine When Water Enters
Combusting is incompatible with water. The job of an engine is to pressurize a mix of fuel and air in the engine cylinders. This mixture is compressible, and it's a perfect process. There is no such thing as a "water bomb.You can't "bomb" water. If a small amount of water enters the cylinder, during the compression stroke, the piston is unable to move. If it isn't the water, then what is it?
Hydrolock The Silent Engine Killer Explained
When water has caused a total mechanical failure in the engine, it's called "hydrolock. If the water is blocking a piston's path as the piston is compressed, the connecting rod connecting the piston to the crankshaft will bend or break under the pressure. In extreme cases the crankshaft will fracture, cylinder walls will crack and the engine block will crack.
This damage occurs instantly. The engine does not slowly deteriorate with time. If there is enough water in the engine, one compression stroke is enough to destroy the engine. The only way to repair a hydrolock is to do a full engine rebuild, which may be impossible. The cost of engine rebuild ranges from one lakh to a few hundred lakhs in Pakistan depending on the type of the vehicle and extent of damages inside the vehicle. Many old pakistani cars cost more to repair than they are worth.
The most dangerous time is when the car stalls in flood water. For every driver, the urge to jump to restart the engine comes as second nature. If water has gotten inside the cylinders, this is the worst thing to do. A water soaked crankcase with water in the cylinders will hydrolock the engine and destroy it as it will try to restart. If your vehicle has stalled in flood water, turn on the flares and call for tow assistance, don't try to start the engine.
Warning Signs Your Engine Was Damaged by Flood Water
You can't always tell if there is damage to the flood water engine. The car may start and run after passing through water and exhibit symptomology within hours or days that are indicative of damage to or contamination of the car.
If your car has been exposed to a lot of flood water, check your oil dipstick right away. If the oil is milky, creamy or greyish in colour, water has mixed with the engine oil. This is a major red flag. If the water is present in the oil, the oil cannot lubricate the engine nearly at all, every minute the engine is running it is operating without the protection of oil. Avoid driving a car. Replace oil and filter and check for any additional damage.
Check for abnormal knock, rattles or rough running after flood driving. The noises can be a sign of bent connecting rods or damaged pistons that have been caused by a partial hydrolocking incident. While the engine may have started and appear to be running, these noises are indications that some internal parts have been stressed beyond their design limits.
The Immediate Checks Every Pakistani Driver Must Do After Flood Driving
In Pakistan, if any car has been driven in standing water, the following checks should be made as soon as possible when the car has again reached a safe dry ground, even if it seems to be driving normally.
Check the Oil, Electrics and Air Filter First
Remove dipstick and check the oil. For milky colour, or a high oil level that wasn't present previously, check for water in the sump. Inspect the air filter housing for water or dirt. A wet air filter is a sign that water got in to the intake system and could have gotten into the engine.
Inspect all electrical connections where possible for moisture. Flood water entering the fuse box, ECU or wiring harnesses can cause short circuits and damage to the sensors which can manifest as electrical issues that may not show up in the next few hours but can become a big electrical problem over the next few days. Check footwells for water penetration. In case there is water in the cabin, the electrical equipment under the carpet and under the seats must be dried as soon as possible.
After any flood exposure, a thorough car wash that includes the undercarriage removes the chemical contamination from Pakistani flood water before it causes rust and corrosion. Harris Car Care stocks car wash products suited to post flood exterior cleaning. Visit harriscarcare.com to find the right products.
How to Drive Through Flooded Streets Without Destroying Your Engine
Avoidance may be the safest way to deal with flooded streets. Take alternate paths, wait until the water level has dropped, or retrace your steps if you cannot determine the water level. However, if there is no alternative, the following technique helps to minimise the risk to the engine.
Start in first gear or lowest gear possible and stay at a slow steady pace. This forms a small bow wave in front of the car, which helps to repel water from the engine compartment. Don't stop after you're in the water. If water gets in between the car, it can equalize around the car to the exhaust and air intake if the car stops. Continue at a steady low pace until you're out of the water all the way.
Turn off AC before entering flood water. The AC condenser is at the front of the car and draws air aggressively through the engine bay when operating. When the AC is off, there is less air movement to draw the water towards the engine's intake.
Do not drive through water if it is more than the middle of your wheels deep. This is where the water is getting close to the engine inlet on most cars in Pakistan and there is a high chance of it causing hydrolock. It's much more dangerous to become trapped in that depth of water than it is to turn around and head back.
Once out of flood water, lightly tap brakes often and drive slowly. The gradual friction created when braking gently will heat the brake surfaces, which in turn will reclaim stopping power before you need it at its maximum, while wet brakes lose friction greatly.
Post Flood Car Detailing and Engine Bay Cleaning
After the initial safety inspections, once you are sure the car is not damaged, a thorough post flood car detailing session prevents the secondary damage that is caused by the flood water in the coming days and weeks.
The flood water in Pakistan is not "pure water". It infuses the road chemical, sewage contamination, organic debris and industrial runoff that remain harmful even when the water dries up. On the exterior paint, this contamination causes etching and accelerated oxidation. Underbody and wheel arches: accelerates rust. It can lead to mould growth and long lasting smells in the cabin.
After a flood, a good car detailing service will address the exterior, remove the chemical film and mud that has adhered to the car's body, and dry and disinfect the interior to remove moisture that may have entered the cabin. A professional engine cleaning cleans away flood water residue on wiring, sensors and other parts that are hard to access and dry in the home, especially in the engine bay.
Post flood detail with ceramic coating offers extra protection which greatly minimizes contamination's bonding to the paint and body panels when it rains again. It is one of the most useful investments in protection of the cars in Pakistan during the monsoons.
Frequently Asked Questions (FAQs)
How do I know if my engine has hydrolock after driving through flood water?
The clearest signs are the engine stalling and refusing to restart, a loud knocking sound during or after the flood exposure, or the engine cranking but failing to fire. If any of these occur after flood driving, do not attempt further restarts. Have the car towed for professional inspection immediately.
Is it safe to do a car wash after driving through flood water?
Yes and it is strongly recommended. A proper car wash after flood exposure removes the chemically contaminated water residue before it etches into paint and corrodes metal. Focus on the underbody, wheel arches, and lower panels where contamination concentrates, using a pH neutral car shampoo to safely remove residue without stripping any protective coatings.
Does car detailing after a flood actually make a difference?
Significantly. Post flood car detailing addresses the contamination that a basic rinse cannot remove. Professional decontamination of the paint, engine bay cleaning, and interior moisture treatment prevents the mold, rust, and electrical faults that develop when flood contamination is left on the car after the visible water has dried.
Can ceramic coating protect my car from flood water damage?
Ceramic coating protects the paint surface from the chemical contamination in flood water by creating a hydrophobic barrier. It does not protect the engine or electrical systems from water entry, but it significantly reduces the paint and body damage that flood water causes when it contacts the exterior.
Drove through flood water this monsoon? Do not wait for the damage to develop. Book a professional post flood inspection, engine bay cleaning, and car detailing session with Harris Car Care at harriscarcare.com and protect your engine and exterior from the hidden damage that Pakistan's flood water leaves behind.