Ask the Mechanic: How deep can I drive through water with a snorkel on my 4WD?
Hello Paul, what is the use of roof high snorkels fitted to 4WD vehicles? Do the owners of these cars drive them through water that is deeper than the bonnet and can they do that safely and without damage?
Jawa
Hello Jawa, roof high snorkels fitted to 4WD vehicles help to elevate the air intake point in order to provide the vehicle engine with cleaner air, especially when driving on dusty roads or wading through flash floods or pools of water. Snorkel kits are very useful when driving over deep water-logged sections of the road or water streams.
When you drive through water with the usual low air intake systems, there is a high risk of water seeping into the engine through the air intake system. This can cause severe engine damage due to a hydrolock (where reciprocating parts of the engine such as pistons are obstructed from moving after a certain amount of liquid has filled in the room where the moving pistons are supposed to be). A professionally fitted snorkel kit can allow you drive through water streams that are as high as your car bonnet.
Precaution should be exercised to avoid intrusion of water into sensitive electrical components on your engine and the rest of the car. As much as the snorkel will protect your engine, the rest of the car may not be insulated like a boat. Caution should also be exercised before and during wading across water streams and flash floods. Often, the fast moving water currents can be deceptive and endanger you and your passengers. Flash floods or streams can carry your car away and lead to a risk of drowning.
WHY SHOULD I SWAP REAR TYRES WITH FRONT ONES?
Hello Paul, I got a flat tyre and went to a nearby fuel station to have it changed. The problem was two nails that had punctured the tyre. Although the tyre was repaired, the mechanic pointed out that the front tyres were worn out and advised me to swap them with the ones at the back, which were in better condition. What advantage is there to have less worn out tyres and why do front tyres wear out faster than the rear ones?
Juliet
Hello Juliet, your mechanic has a point; swapping the less worn out rear tyres with the more worn out front tyres will improve the performance of your car brakes and help enhance car handling and traction. Front tyres work harder than the rear ones because they handle most of the stress due to brake force.
A lot of the vehicle weight distribution weighs more at the front axle where the engine is located, which adds stress to the front tyres, especially during braking. Steering also adds to front tyre stress due to friction as they turn on the road surface. This contributes to faster wear compared to rear tyres.
WHAT IS THE CRUISING SPEED LIMIT FOR TRUCKS ON UGANDAN HIGHWAYS?
Hello Paul, I ask this out of concern since I drive daily. What should be the open road cruising speed of a truck which is designed for the job it is doing, is in good condition, is properly loaded and proficiently driven?
Cornelius.
Hello Cornelius, the speed limits in Uganda depends on the area where you are driving and the type of vehicle. For trucks, the highway top speed should not exceed 80 KPH. The truck driver should observe speed signs and adhere to the lower speed limits set for all vehicles when driving through trading centres, city centres, junctions and curves such as 50, 30 or 5 KPH.
Speed limits are set based on the design of the road, curves, terrain of the area, the environment of the road, nature of traffic flow and junctions among other factors.
Speed limits take into consideration the braking distance of a particular vehicle in the event of emergency braking. That is why a heavier truck has a lower speed limit than the lighter Sport Utility Vehicle or saloon vehicles.
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