It might be a bit too cold to change the oil on your WW2 jeep right now.  However, it won’t be long when you will need to climb under the jeep, turn some wrenches and get that oil changed.

I really do hate dirty oil, don't you?

I really do hate dirty oil, don’t you?

Occasionally it will be necessary to flush the oil system because of an accumulation of sludge or other foreign material. Here are some instructions from WW2 manuals:

  • Drain the oil from the system after warming the engine to normal operating temperature. Be sure to use CAUTION as the oil will be HOT.
  • Fill the oil pan to half the indicated level with light engine oil.
  • Start the engine and allow it to warm up thoroughly. This will allow the light oil to clean the system. Watch the oil pressure gage, and stop the engine at the slightest sign of low oil pressure. This may be caused by a clogged strainer.
  • When the engine is thoroughly warmed, turn off the engine and drain the oil.
  • Fill to the proper level with the correct engine oil.
  • If the oil filter has a replaceable filter element, inspect it and replace if necessary.
Caution: These are recommendations from WW2, always consider if this practice is considered safe for you or your equipment for proceeding. If you follow these instructions I would use extreme caution and watch closely the oil pressure gauge. I would also try using 10w oil as my “cleaner” and I would fill it till it was at the full mark instead of half. The sump pickup in a jeep may not pickup the oil if it is only half full. I suggest always changing the oil filter when changing the oil. But I wouldn’t change the filter until after the cleaning. Again, exercise caution.
Whether you new at mechanics or just new around WW2 military vehicles, you might be interested in Automotive Trouble Shooting for WW2 Wheeled Vehicles: Volume 1 and Automotive Trouble Shooting For WW2 Wheeled Vehicles, Volume 2.