Engine Aluminum Spacer Deck Pitting Caterpillar

Problem:

There have been instances where the engine's aluminum spacer deck assembly gets excessive pitting when the coolant is not kept to proper specifications.

Solution:

Some of this pitting may be inhibited by installing an orifice at the outlet of the coolant temperature regulator housing. By installing an appropriate orifice in that location, the coolant flow is slowed down. This reduces the effects of coolant velocity. The orifice also provides backpressure on the coolant system to decrease cavitation erosion.

NOTE: This technique is most useful when installing a new spacer deck during overhaul but may provide added benefit on older units.

Fabricate an orifice from 1/4 thick stainless steel as shown in Illustration 1.

To install the fabricated orifice:

1. Remove the upper radiator hose from the coolant temperature regulator housing.

2. Insert the fabricated orifice approximately 1/2 inch into the end of the radiator hose that was removed from the regulator housing. See Illustration 2.

3. Install the radiator hose on the regulator housing back to the hose's original position. This will push the orifice further into the hose and keep orifice correctly oriented in the hose.

4. Place one hose clamp in the original position on the radiator hose to keep the hose in position on the regulator housing.

5. Place a second hose clamp on the hose so that the clamp is over approximately 50 percent of the orifice and 50 percent downstream of the orifice.

Illustration 1.

Dimensions For Fabricated Orifice. The orifice must be fabricated from stainless steel.

Illustration 2.

Installation of fabricated orifice.

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