GMC GMT 610, Manual, Page: 24 / 80

G/H Van (GMT 610) 2005
G/H V
AN
(
GMT 610
)
20
P
AGE
Section 13 — Cooling
To provide satisfactory engine cooling and A/C performance, the following conditions must be met:
1 . Do not locate any large objects such as batteries, spare tires, lights/sirens, etc., in front of the radiator core, A/C condenser or
grille. They restrict air flow into the radiator core and influence fan blade stress and/or A/C head pressure.
2. Grille opening size, configuration and the external baffles provided should not be altered in any manner. Any reduction in cooling
ability may adversely affect engine/transmission performance.
3. Fan clutches not conforming to the original equipment specifications may not operate correctly and may stay “on”
continuously, never come on, or cycle on and off excessively. This may result in a reduction of fuel economy, engine overheat at
times, or annoying cycling.
4. Heavy duty cooling equipment is required when air conditioning, auxiliary belt driven equipment, snow plows, winches, etc., are
installed.
5. Continuous coolant flow is necessary from the heater connection on the engine to the heater connection on the radiator or water
pump in order to control transmission oil temperatures during closed thermostat (warm-up) operation. Do not alter this flow as it
may result in premature engine or transmission failure.
6. If a heater unit is not installed in the vehicle or a heater shut-off valve is required, a line connecting the heater connection on the
engine to the heater connection on the radiator or water pump must be installed. When a shut-off valve is required in the heating
system, it must be teed into the system in such a manner as to maintain continuous flow between engine heater connection -
radiator heater connection at all times.
Do not over fill coolant recovery or surge tank containers.
Be sure to add coolant to system after adding capacity to system heaters. The use of environmentally friendly long life coolant is required.