RETAINER AS-SEAL 4D4506 - Caterpillar

All Caterpillar EnginesThere have been reports that steel wire brushes have been used to clean injection nozzle tips. Wire brushes are also being used to clean cylinder heads with the nozzles still in the head. This method of cleaning injection nozzles can give lower engine performance.
For example, when a direct injection nozzle is cleaned with a steel wire brush, metal around the nozzle orifice can be rolled into the orifice. This makes the orifice smaller. See the illustration. The smaller orifice will cause a decrease in fuel flow that results in lower engine performance.
If a fuel nozzle tip must be cleaned, use an 8S2258 Nozzle Cleaning Brush from the 8S2245 Injector Cleaning Tool Group. This is a brass wire brush.
A nozzle that has been cleaned with a steel wire brush can give acceptable results during the nozzle test because none of the internal parts were damaged. Close visual inspection is necessary to find this problem.
The nozzle on the right has been cleaned with a steel wire brush. The orifices have some metal rolled into them. The nozzle on the left has not been cleaned and has orifices with sharp edges like a new nozzle.