Md. Code Regs. 11.14.02.06

Current through Register Vol. 51, No. 12, June 14, 2024
Section 11.14.02.06 - Exhaust System
A. The exhaust system includes the exhaust manifold and all piping leading from the flange of the exhaust manifold, to and including the muffler, resonator, and the tail piping.

Procedures:Reject Vehicle If:
(1) With engine running and the vehicle on a hoist or lift, visually inspect the exhaust pipes, mufflers, resonators and tail pipes for leaks, deterioration, proper mounting, damage, and general condition. Rusted or corroded areas shall be given particular attention. Holes in the system made by the manufacturer for drainage are not cause for rejection.(1) Vehicle has no muffler.
(2) Light trucks equipped with a cap or slide-in camper shall have a full length tail pipe extending beyond the rear wheels and exiting beyond the side or rear of the body.(2) There are loose or leaking seams or joints.
(3) On all other vehicles the tail pipe shall be located as originally designed by the vehicle manufacturer, or if not as originally designed shall extend beyond the passenger or occupant compartment and enclosed cargo area if it is open to the driver or passenger area. The tail pipe shall extend at least to the front of the rear wheels, beyond the rearmost door opening, and exit beyond the side or rear of the body.(3) There are holes caused by damage, corrosion, or temporary repairs made to the exhaust pipe, muffler, resonator, or tail pipe. Welding or brazing is considered a permanent repair if it does not leak.Elimination of a resonator alone is not cause for rejection as long as the vehicle has an effective muffler.
(4) Type II school buses shall have a full length tail pipe extending beyond the rear wheels and exiting beyond the side or rear of the body unless the vehicle is equipped with a left side exhaust system which meets the following criteria:(4) Tail pipe end is pinched or obstructed.
(a) The exhaust pipe may not passwithin 12 inches of the fuel tank or its connections unless a suitable baffle is installed between the exhaust system and these components.On vehicles with left side mounted fuel tanks, compliance with this requirement may be more difficult; however, this requirement shall still be met.(5) The system is not properly mounted, securely fastened, or if the seam of a muffler or resonator on a type II school vehicle faces the fuel tank, fuel lines, or floor of the vehicle.
(b) No part of the exhaust system may pass within 12 inches of any flexible brake hose, solid brake line, or flexible fuel line unless a suitable baffle is installed between the exhaust system and these components.(6) There are loose muffler baffles; the vehicle is equipped with cutout or similar device; or the system is not original or equivalent.
(c) The exhaust pipe should be approximately a 45-degree angle as it approaches the left body line to prevent back pressure and heat buildup (see diagram).(7) Any part of the system passes through the occupant compartment, or there are any leaks in the heat exchange boxes or ducts of vehicle using engine exhaust heat to warm the interior of the vehicle.
(d) The exhaust pipe shall be deflected downward as it approaches the left side of the body.(8) The tail pipe on light trucks equipped with a cap or slide-in camper or a type II school vehicle is not full length, or does not extend beyond the rear wheels and exit beyond the side or rear of the body.
(e) The exhaust pipe shall exit behind the driver's compartment.(9) The tail pipe on all other vehicles, if not as originally designed by the vehicle manufacturer, does not extend beyond the occupant compartment and the enclosed cargo area if it is open to the occupant compartment, to at least the front of the rear wheels and beyond the rear of the rearmost door opening, or does not exit beyond the side or rear of the body.
(10) Exhaust pipe, muffler, or tail pipe is not of a leak proof construction. Flexible pipe that does not leak is acceptable, except on type II school vehicles.
(11) It emits continuous exhaust fumes or smoke which obscures persons or objects from a clear rear view.
(12) On the type II school vehicle, the system passes directly under the emergency door, or there is any reduction in the size of the tail pipe after it leaves the muffler.
(13) A type II school vehicle with left side exhaust does not meet the requirements established.

Md. Code Regs. 11.14.02.06

Regulation .06 amended effective April 1, 1991 (18:6 Md. R. 686); February 1, 2012 (39:1 Md. R. 18)