SHAFT AS-YM 4574596 - Caterpillar

Illustration 1. Standard.The commercial folded cores for the 3400 and 3500 Families of Engines use the opposite or "reversed" gap position that provides better heat tranfer performance but is more sensitive to applications where debris exists. The "reversed" gap positions the 2.0 mm (.08") gap on the downstream side of the radiator while the 6.5 mm (.26") gap now is on the upstream side. The "reversed" gap positioning requires that the 2.0 mm (.08") gap on the grill side be adjusted and that the larger gaps be observed (not set) to be approximately 6.5 mm (.26"). See Illustration 2.
Illustration 2. Reversed.For both "standard" and "reverse" designs, the gaps should be close to the correct spacing with the strap assembly bolts loose. In both designs, only the downstream (grill side) gaps should be adjusted (6.5 mm standard - 2.0 mm reversed). Forcing the cores either closer or farther apart causes the core to bow in the middle since the cores are fixed at either end by the locating dowels. Excessive bowing could initiate stresses that could lead to failure of the module.