system. A coolant shutoff valve shall be provided for the coolant inlet side of the
fuel warmer unit. The unit shall not cause heating of the fuel above 27°C (80°F)
under any possible condition.
An in-tank fuel warmer or preheater unit shall be provided on diesel engine driven
vehicles. The unit shall use engine coolant to transfer heat to the fuel in one fuel
tank. The warmer shall not cause heating of any fuel above 27°C (80°F) under any
possible condition, shall not disable or cause elimination of the fuel gage sending
unit and shall not violate 3.2.1 or any Federal Motor Carrier Safety Regulation. A
coolant shut off valve shall be included. The units required by 188.8.131.52(c) and (d)
may be combined.
184.108.40.206 Fuel fired engine preheater. When specified (see 6.2), for diesel engine driven
vehicles, a diesel fuel fired engine water heater shall be furnished to preheat the engine. The
heater shall include a timer, a thermostat and a circulating pump, and shall be connected to the
engine coolant system. The heater shall be capable of starting and operating at -51°C (-60°F) and
shall heat the engine to +4°C (+40°F) from -51°C (-60°F) in not more than 1 hour. The system
shall be equipped with a light, visible to the driver, to indicate that the preheater is operating. The
system shall include fuel warmers or preheaters conforming to 220.127.116.11(c) and (d).
18.104.22.168 Vernier throttle control. When specified (see 6.2), a manual vernier controlled
throttle with quick release shall be furnished, except on electronically controlled engines.
3.4.2 Electrical systems. The electrical system shall be in accordance with Federal Motor
Carrier Safety Regulations 393.27 through 393.31 and 393.33.
22.214.171.124 Starting system. A 12- or 24-volt direct current (dc) starting system with 12-volt
dc lighting system shall be furnished. Engine starting equipment shall include an ether starting
system, glow plug or electric grid heater. If an ether system is furnished in lieu of a glow plug or
grid heater, it shall be of the measured shot type. The measured shot type ether system shall be
key operated or manually operated from the driver's compartment and shall be inoperative with
the engine warm. Complete provisions for a replaceable ether reservoir of not less than
355 milliliters (mL) (12 fluid ounces) shall be furnished. A reservoir need not be furnished.
When specified (see 6.2) the starting motor shall be equipped with a thermostat controlled,
automatic resetting circuit breaker that will protect the motor from overcrank heat damage. The
circuit breaker shall not limit cranking ability for a startable engine.
126.96.36.199 Ignition system. For gasoline engine driven vehicles, a 12-volt dc ignition system
shall be furnished.