Yanmar 1GM10 Shop Manual Download

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CHAPTER THREE

Freshwater (Closed) Cooling Systems

Inspection

WARNING

When performing any service work on the
engine or cooling system, never remove the
pressure fill cap on the exhaust manifold
(Figure

drain coolant or disconnect

any hose while the engine is hot. Scalding
fluid and steam may be blown out under

pressure and cause serious

Once a year, or whenever troubleshooting the cooling

system, check the following items. If the proper equip-
ment is not available, have the tests performed by a radia-
tor shop.
1. Loosen and remove the pressure fill cap (Figure

24).

2. Check the cap seals for tears or cracks. Check for a
bent or distorted cap. Rinse the cap under warm tap water
to flush away any loose rust or dirt particles.
3. Inspect the cap neck seat for dents, distortion or con-
tamination. Wipe the sealing surface with a clean cloth to
remove any rust or dirt.
4.

Check the fluid level and fill the system if necessary as

described in the

Coolant section in this chap-

ter.
5.

Check all cooling system hoses for damage or deterio-

ration. Replace any hose that is questionable. Make sure
all hose clamps are tight.
6.

Check the heat exchanger (Figure

25)

for cracks or

damage. Service, if necessary, as described in Chapter
Eight.

coolant (not equipped with

remote reservoir)

WARNING

Do not remove

pressure cap (Figure

24) from the pressurized cooling system
when the engine is hot.

1. Loosen and remove the pressure fill cap (Figure

24).

2. Check the level of fluid in the system. It should be
level with the iron plate at the bottom of the filler neck.

NOTE

Excess coolant (above proper level) will be
expelled when coolant reaches operating
temperature.

3. If the exhaust manifold is not properly filled, add cool-
ant. Refer to the Coolant section in this chapter for proper

coolant.

Heat
exch

Coolant (Equipped With a

Remote Reservoir)

Refer to Figure

26.

Check the level of the coolant in the remote reservoir

tank (Figure 26) when the engine is cold. The coolant
level should be between the marks on the tank.

2. If the coolant level is low, but the tank is not dry, add
coolant to the tank. Refer to the following section for the
proper coolant mixture.

WARNING

Do not remove the pressure fill cap (Figure

24) from the pressurized cooling system
when the engine is hot.

If the coolant level is low, but the tank is dry, remove

the pressure fill cap on the exhaust manifold (Figure

24).

Add coolant to the exhaust manifold so it is full, replace
the cap, then add coolant to the remote reservoir tank to
the proper level.

4. Run the engine until it reaches normal operating tem-
perature, then let the engine cool. Recheck the coolant
level in the remote tank and, if necessary, refill the remote
reservoir tank.

Coolant

Only use a high-quality ethylene glycol-based anti-

freeze designed for aluminum engines. Mix the antifreeze
with water in a

ratio. Coolant capacity is listed in

Table

When mixing antifreeze with water, use only soft

or distilled water. Distilled water can be purchased at su-
permarkets in gallon containers. Do not use tap or salt wa-
ter because it will damage engine parts.