Bulletin No. 4.10-7 Group No. 4.10 February 15, 2005 Page 1 of 1

THE TRASH CAN

Oil coolers

To assure full engine life on newly rebuilt engines, cleanliness is vital. While inspecting the failed parts from warranty claims, we frequently find that contaminated lube oil was the primary cause of failure. The frequently failed parts are: connecting rod bearings, crankshaft main bearings, camshafts, camshaft bushings, tappets, oil pumps, pistons, piston skirts and piston pins. One possible source of the lube oil contamination is a dirty oil cooler. It is very difficult to completely and properly clean a used oil cooler. The oil cooler is one of the most over looked sources of contamination. If the engine to be rebuilt has had one of the following failures: spun bearings, flattened camshaft lobe, tappet failure, rocker shaft or arm, or other major internal component failure, we strongly suggest that the oil cooler be replaced. The oil cooler can be like a trash can; collecting debris from internal component failure. In order to avoid premature engine failure, we recommend replacing the oil cooler. Cleaning the oil cooler is not advised. In fact, O.E.M. technical manuals suggest that oil coolers be replaced after 4,500 hours of use and always during major overhaul.

The engine block should have all its soft plugs, pipe plugs and piston-cooling jets removed for a thorough cleaning of all oil galleys. The oil filter and oil bypass housing should also be disassembled, cleaned and checked. The rocker arm shaft also should have its soft plugs removed and cleaned. If the above procedures are followed, your time and money in rebuilding an engine will be well spent.

Remember – clean environment, clean parts, clean oil – means a clean engine!