The genuine STIHL 9638 003 1581 Crankshaft Oil Seal is a high-quality OEM rotary shaft seal designed to maintain proper crankcase sealing in STIHL petrol chainsaws. This seal prevents air leaks and oil loss around the crankshaft, helping maintain correct crankcase pressure, fuel delivery and engine performance. It is commonly replaced during engine rebuilds, crankshaft servicing or when diagnosing lean running, hard starting, erratic idle or air leak issues.
Fits STIHL Models
- 017
- 018
- 019T
- 021
- 023
- 025
- 028
- 028 AV
- MS 162
- MS 162 C
- MS 170
- MS 170 C
- MS 171
- MS 171 C
- MS 172
- MS 172 C
- MS 180
- MS 180 C
- MS 181
- MS 181 C
- MS 182
- MS 182 C
- MS 190 T
- MS 191 T
- MS 210
- MS 210 C
- MS 211
- MS 211 C
- MS 230
- MS 230 C
- MS 231
- MS 231 C
- MS 250
- MS 250 C
- MS 251
- MS 251 C
- MS 270
- MS 270 C
- MS 271
- MS 271 C
- MS 280
- MS 280 C
- MS 291
- MS 291 C
- MS 311
- MS 391
- GS 461 Concrete Saw
Workshop Note
STIHL commonly specifies 9638 003 1581 as a replacement-style crank seal that can be installed without fully splitting certain crankcase assemblies, while 9639 003 1585 is typically used when the crankcase has already been separated during a complete engine rebuild.
