Cooling System - HUSTLER 3500 Owner's Manual

It is important to note that whenever an air filter element is
cleaned by any method, the person or company performing the
cleaning assumes responsibility for the integrity of the filter
from then on. The warranty for air filters expires upon
cleaning or servicing in any manner because the condition of
the filter after servicing is completely out of their control.
Therefore, on a dust ingested engine failure, there will be no
warranty consideration if the air filter element has been
cleaned or serviced in any manner.
A partially dirty air filter element works better than a new
element. Therefore, a dirty filter element is not bad for the
engine unless it is excessively restricting the air flow and engine
performance is affected. The reason is simple. The media in the
filter must be porous to allow air to pass through it. When dirty
air passes through the filter, the dirt plugs some of the holes in
the media and actually acts as part of the filter media. When the
next round of dirt enters, the first dirt helps filter out even
smaller particles making the filter more efficient at stopping dirt
from entering the engine. This is referred to as barrier filtration.
Of course, at some point the filter media becomes too clogged
to allow air to pass.
The mowing conditions will determine the frequency of air
filter element changing.
Air filter
Figure 4-16

Cooling system

The 3500/3700 engine must operate at the correct temperature
to obtain maximum efficiency and service life. This is
dependent on the cooling system.
Always fill the system with a 50/50 solution of permanent
antifreeze and clear water.
Checking the coolant level
WARNING: Always wear eye protection when ser-
vicing the cooling system.
NOTE: Visually inspect the system daily prior to operating
tractor. Be sure the engine is level. Open the hood, and check
the coolant recovery reservoir located next to the battery. Check
the coolant level only when the system is cold. Check the
109627_0910
coolant level only at the overflow reservoir (Figure 4-16). The
cooling system is a closed type. Never open the radiator cap.
Doing so may induce air into the cooling system and may cause
overheating. The coolant level should be between the low and
full marks on the reservoir.
If the coolant recovery reservoir is low, refill system, with the
proper coolant mixture, through the recovery reservoir. It is not
necessary to remove the radiator cap to replenish the coolant.
Engine cooling is accomplished with a 50/50 mixture of clear
water and Ethylene Glycol (anti-freeze). This mixture will
provide freeze protection to -32° F (-34° C).
The radiator is equipped with a pressure cap and overflow
reservoir.
DANGER: Never remove radiator cap or overflow
reservoir cap when engine is hot. Pressurized hot
steam and water may be released, causing serious
burns or possible blindness.
The cooling system operates under pressure controlled
by the radiator cap. It is dangerous to remove the cap
while the system is hot. Always cover the cap with a
thick cloth and turn it slowly counter-clockwise to the
first stop. Allow all pressure to escape before remov-
ing the cap completely.
Be sure that the radiator fins are clear of chaff and dirt to
allow free air movement.
Radiator
screen
Coolant
recovery
reservoir
Draining and flushing the cooling system
NOTE: Drain and flush the radiator and engine block every
12 months. Refill with a 50/50 mixture of permanent antifreeze
and clear water.
4-9
Figure 4-17