Apply Heat To A Cold Engine - Lycoming IO-390-D Series Installation And Operation Manual

Condition
Sluggish propeller operation
Overheating
(The temperature of the system
components is greater than the
maximum design operating
temperature for the components.)
Overspeed
Volcanic ash
Engine soaked in water

Apply Heat to a Cold Engine

If an engine is in cold weather longer than 2 hours (at temperatures less than 10°F (-12°C) it can
become "cold soaked." At these extremely low temperatures, oil can become thicker, battery
capacity decreased, and the starter could be operated above capacity. Incorrect cold weather starting
can cause unusual engine wear, decreased performance, shortened time between overhauls, or engine
malfunctions. In the "cold soaked" condition, fuel can vaporize too slowly which could make engine
start difficult.
NOTICE: Pre-heat application will help the engine start during cold weather and is necessary
when the engine has been in sub-freezing temperature + 10º F (12ºC). Do not use small
electric heaters (which install in the cowling opening) to warm up an engine because
they do not apply sufficient heat.
Do not use a heated dipstick to apply heat because heat will be concentrated and not
applied throughout the engine. Concentrated heat can cause damage to non-metal engine
parts. The oil must be warmed to flow to all parts of the engine.
If the engine is not equipped with a commercially available engine pre-heating system:
1. Use a high volume air heater to apply heat.
2. Apply hot air to all parts of a cold-soaked engine.
3. Make sure the engine oil is in compliance with the recommended grades in Appendix A.
WARNING
4. To ensure uniform heat application, apply hot air to the following parts in 5-minute intervals
for a minimum of 30 minutes:
• Oil sump
• Oil filter
Engine Conditions
Page 42
IO-390-D Series Engine Installation and Operation Manual
Table 1 (Cont.)
Action for Engine Conditions
Make a safe landing and speak to Maintenance.
Make a safe landing as soon as possible, and identify and
correct the cause. Refer to the IO-390-D Series Engine
Maintenance Manual
Refer to the section "Overspeed" in this chapter.
Refer to the section "Volcanic Ash" in this chapter.
Refer to Chapter 05-50 in the IO-390-D Series Engine
Maintenance Manual.
IF HEAT HAS NOT BEEN APPLIED TO ALL PARTS OF THE ENGINE,
THE ENGINE CAN START AND RUN BUT LATER FAIL AFTER
APPLICATION OF HIGH POWER BECAUSE THE OIL WILL NOT
FLOW FULLY THROUGH THE ENGINE. DAMAGE CAN OCCUR AND
NOT BE KNOWN UNTIL AFTER SEVERAL HOURS OF OPERATION.
• External oil lines
• Oil cooler
Action
• Cylinder assemblies
• Air intake.
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March 2020