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5.3l (lm7) Coolant Flow Direction

BlueH2o

By BlueH2o
in Ask A GM Technician

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BlueH2o New Member

BlueH2o

Posted
Posted

Can anyone tell me the direction of coolant flow in the 5.3L Vortec (LM7) engine (2004 Silverado)? Does it flow from the bottom radiator hose port through the thermostat to the block/heads out the water pump to the top hose or vice versa? Have looked all over the net and there are many "opinions" but having difficulty nailing this one down. Just replaced the t-stat, hoses, coolant, and am quite surprised at the temp difference btwn the top and bottom hoses. Truck is running fine and the temp gauge is where it should be, but am curious about the direction of coolant flow and Haynes isn't as forthright with the info...thx.

00Silverado4x4 Senior Enthusiast

00Silverado4x4

Posted
Posted

There is suppose to be a difference of temp between the top and bottom radiator hoses because you have a radiator between them cooling down the fluid. The flow will be from the hot hose to the "cooler" hose. Typically top to bottom using gravity to assist in flow. This isn't always true as I have worked on liquid cooled engines used in generators that were backwards (for some unknown reason.)

Doug_Scott Senior Enthusiast

Doug_Scott

Posted
Posted

Should be top to bottom. Generally the thermostat is on the "outlet side" of they system. So locate the thermostat, and the coolant will flow out of the engine at that point.

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