A stock vehicle will generally have an air intake somewhere inside one of the front fenders/quarter panels. This means it will be low and close to the ground and being close to the ground means
the vehicles intake will be move prone to suck in dust and if submerged in water it will have no choice but to suck in water which will lead to catastrophic engine failure.
A diesel engine will be destroyed by just a small amount of water whereas a petrol motor could survive a small amount but it’s certainly not worth the risk.
The 4wd snorkel helps prevent dust and will prevent water from entering the engine as long as the water level doesn't exceed the height of the 4x4s roof/snorkel height.
A special sock can be added to the top of a snorkel and these will act as a second air filter.
They are good for catching leaves from trees that may have
come in contact with the snorkel, also great for catching real fine dust
particles (bull dust).
Do it yourself will take about half a day and most snorkel kits come with a cutting template and instructions. However you will require a hole saw with a drill.
Getting a snorkel installed by the supplier means you will get a warranty in case of a water leak due to it not being water tight. You stand a better chance to get something fixed by the installer/supplier than if you had installed it yourself.
After installation (even if installed by a supplier) make sure to check the air intake box as on most 4wds there will be drainage holes, if these are not blocked water may enter the engine.
The holes are generally only the size of match stick head. Plug these holes with silicone or something similar (make sure whatever is used can withstand heat) and let it dry before switching the engine on.
On all vehicles or anything that has an engine you will also find an air filter in a box (Air filter box) which will be attached close to the engine.
These filter the air and prevents dust, sand, leaves and anything else from entering the engine.
In most cases installing an aftermarket air filter will increase the performance of the vehicle. Some of these are reusable filters like the “K&N filter”.
Purchase a cleaning kit along with them or ask the mechanic to clean the filters when servicing the vehicle.
Over time (about 3-4 service intervals) the cleaning kits will pay for themselves.