5.4 SD roaring under load
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Joined: Oct 2010
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5.4 SD roaring under load
My 01 5.4 SD sometimes "roars", makes a loud noise, when towing a heavy trailer or with a heavy load in the bed when accelerating. It can usually be stopped by backing off on the accelerator momentarily. Any ideas?
Sit. Stay.
Joined: Oct 2001
Posts: 18,308
Likes: 20
From: Washington State
Your truck's engine is equipped with a fan clutch.
This "clutch" works so that when the fan is not needed to cool the engine it will have the fan run at less than 1 to 1 with the engine. Meaning: it turns slower than the engine. This is done for fuel economy and performance reasons.
The clutch is controlled by heat that comes from the radiator. If the heat from the radiator is is beyond a certain threshold, the fluid inside the clutch will thicken and make the fan spin 1:1 with the engine. This is the roar that you hear.
This "clutch" works so that when the fan is not needed to cool the engine it will have the fan run at less than 1 to 1 with the engine. Meaning: it turns slower than the engine. This is done for fuel economy and performance reasons.
The clutch is controlled by heat that comes from the radiator. If the heat from the radiator is is beyond a certain threshold, the fluid inside the clutch will thicken and make the fan spin 1:1 with the engine. This is the roar that you hear.
