No, it is not. BUT: Starting a car with the exhaust submerged carries other risks. By implication there are other things submerged that could be damaged by water, such as the alternator, HVAC, or transmission. Also, the engine may not start if the starter cannot overcome the water pressure.
Take ou starter off and have it tested could be that the brushes shorted out
Your timing belt has probably worn out, or broken, and has jumped timing.
No, they do not go that deep
Is it gas fumes or exhaust? The only cause for a fuel smell inside the vehicle would be a fuel leak, so check the lines, tank, etc. for that. While you're underneath, check the exhaust. Sometimes exhaust can have a similar odor to fuel, so check for exhaust leaks under the vehicle and also check your rear door seals and trunk seals for damage or poor seal. Sometimes exhaust can be sucked in through poor seals. If you are unwilling or unable to get under the vehicle to check for exhaust and/or fuel leaks, take the vehicle to a shop and explain your concerns and ask that it be inspected. Breathing either fuel vapors or exhaust can have serious health and safety risks, so be proactive, do something about it before bad things happen.
The purpose of the EGR valve is to direct some of your exhaust gas right back into your intake. Hence the name: Exhaust Gas Recirculation. Sounds pretty ridiculous, huh? Well, exhaust gas actually helps your engine warm up more efficiently (so the valve is open when the block's cold), then the valve's supposed to shut off that exhaust intake when you're warm. If it stays open exhaust is always recirculated into the engine. It would be like taking your air filter off and driving continuously through a tunnel filled with exhaust. Nice, huh? The life, gas mileage, and horsepower of your engine are all reduced.
Yes if it is submerged or you stuck a water hose in the breather inlet. Or maybe its possible if the vehicle was driven through water too fast, maybe.
Yes
When submerged in water, it may get water conatmination. Also the thermal shock, when exhaust is put in water may easily damage the o2 sensor. Some sensors are vented through cables and some through a special hole. Those with hole, are more likely to get water contamination.
Exhaust gasses are escaping through a hole or rotted section of exhaust system
Through osmosis in the root hairs or from cell surface in submerged aquatic plants.
as hot as the exhaust manifold there are exhaust gases passing through it
That is called condensation. When you start the engine the exhaust system/pipes are cold. When the heat from the engine exhaust passes through the exhaust it makes it sweat. That is normal.
The exhaust is expelled directly from the engine using straight pipes through the stern of the boat, above the water line. Normally high speed boats are equipped with these types if exhaust system.
why does a 1971 454 chevelle 2hrs. running time back fire through the exhast possible the firing order is not correct, valves not adjusted properly,
A ductless exhaust provides a short channel for the airflow to pass through, while a ducted exhaust provides a pathway to move the air far away.
As a rule exhaust is emitted on the opposite side of the fuel filler tube on single exhaust vehicles for safety reasons.
possible causeThe muffler is extremely hot after mowing, when the ignition is turned off, the fuel air mixture continues to be drawn into the engine through the carburetor and when the engine comes to a complete stop the fuel air mixture is now stalled and what is in the muffler is ignited by the header pipe, muffler or exhaust valve. The loud bang is the unmuffled explosion of the air fuel mixture.