Dodge: Cummins temp swing, temperature fluctuation, cummins engine

Question
-------------------------
Followup To
Question -
I have a 94 Dodge with the Cummins engine. The temp was hanging at the bottom edge of the range, so I replaced the thermostadt. Now it climbs to 180, but then drops quickly to the low range, and slowly climbs back up, then continues the cycle.
Answer -
Check inside the radiator to see if it has any buildup in it.If it does have it rotted out.Could be poor coolant circulation.Also if the system has air in it will cause temperature fluctuation.

Great, I'll take a look. As far as the air goes, there is a hose that bypasses the thermostat. It should poll the air out. Is there another place I need to bleed?

Answer
Dan,
No bleeding needed.Check these for defects.
1.Check the drivebelt for proper adjustment.
2.Make sure the core of the radiator is not blocked with debris.
3.Check the fan blades for cracks or broken blades.
4.And the main one.Have the radiator cap pressure tested to see if it's maintaining the proper pressure.
All these symptoms can and will cause the problems you are having.Keep me posted....RamMan