What happens if your exhaust pipe gets clogged?

Answer 1

One of a number of things can happen if your exhaust pipe becomes clogged.

- If the obstructing object isn't too tight, the engine will likely simply blow it out, easily if loose or with quite bang if tight. Something like dirt, snow, or if someone is pranking you with a banana in the tailpipe, they'll all just blow out. However, something like a rock, dent, or crimped pipe won't clear out.

- If the object wont blow out, but is only partially blocking, the engine will likely still run. If the obstruction is minor, there may be no noticeable effect at all. If the blockage is moderate, loss of power, decrease fuel mileage, and perhaps an audible hiss or whistling sound might be heard.

- If the blocked is sever, the engine performance will be more harshly effected, with large loss of power and RPMs being limited as the engine can't rev up. Overheating might occur as the hot gases can't escape away from the engine properly if run long. A loud hiss or whistling sound can often be heard. The engine will often act as if it's in too high of gear, lugging knocking and eventual stalling.

- With a complete blockage the engine may start, run a few moments till the exhaust pressure builds up to a point it's to great for the engine to expel enough to fumes to be able to breath in fresh air and fuel to burn, at which point it will stall and not restart. Note, some car exhausts will have a small drain vent in the muffler to allow condensation to drain out. Those cars might restart after some prolonged cranking, but will stall again once the pressure is too great.

In all cases, there is a risk the exhaust system my fail, if old or rusted. Parts could break loose or the muffler might "explode" apart from the pressure. However the good news is, NO permanent damage should be done to the engine once the obstruction is cleared. The engine only fails because it's not able to breath properly, not because of any mechanical damage.

Unlike some might think, NO exhaust fumes should enter the passenger compartment so long as the pipes are in proper working condition. They will block any fumes from leaking into the passenger spaces.

Note, on smaller engines, particularly 2 cycle engines, their exhaust can become clogged on their own from carbon and soot build up internally. This is not uncommon for this type of engine, used on older dirt bikes, boats, atvs, weed weeders, and other small engines.