Variable Coolant Pump

WARNING: This page is about a different variant/trim than selected.

Courtesy of JAGUAR LAND ROVER NORTH AMERICA, LLC

ITEM	DESCRIPTION
1	Electrical connector - Variable coolant pump shroud solenoid
2	Electrical connector - Variable coolant pump shroud position sensor
3	Pulley

The variable coolant pump is installed at the front left of the cylinder block. A pulley attaches to the pump flange. The ratio of crankshaft speed to variable coolant pump speed is 1:1.45.

For additional information, refer to: ACCESSORY DRIVE

The Powertrain Control Module (PCM) controls the variable coolant pump to give the minimum flow to support all cooling requests from the engine components. The variable coolant pump has a shroud inside that slides over the impeller to control the quantity of engine coolant pumped into the engine. The purpose is only to pump the minimum quantity of engine coolant necessary around the engine. This decreases the load on the engine and improves fuel consumption and emissions.

Variable flow functionality is used during warm-up, contributing to the whole engine thermal management strategy. The internal pressure within the variable coolant pump acts against a return spring in the variable coolant pump housing. The variable coolant pump shroud solenoid is open without a signal from the PCM. Therefore the variable coolant pump shroud returns to its base position under spring force, resulting in full flow from the variable coolant pump.

As components warm up, the flow request increases in 4 stages. The engine coolant flow control continues until the complete powertrain system, including the transmission, achieves its operating temperature.

NOTE: Flow percentages are approximate values.

The flow modes of the variable coolant pump are the following:

Level 1 = 15% of the total flow.
Level 2 = 25% of total flow.
Level 3 = 50 % of total flow.
Level 4 = 100% (Maximum flow).

NOTE: If engine is not running, the default pump shroud position is Level 4 or fully unshrouded (safety position).

The Powertrain Control Module (PCM) receives input signals from the following components to calculate the level of coolant flow required:

Engine speed - Crankshaft position (CKP) sensor
Engine Coolant Temperature (ECT) sensor
Cylinder head temperature sensor
Radiator outlet temperature sensor
Ambient Air Temperature (AAT) sensor
Cylinder block temperature sensor
Engine oil pressure and temperature sensor
Engine torque
Fuel consumption (modeled in the PCM)
Automatic Transmission Fluid (ATF) temperature from the Transmission Control Module (TCM)
HVAC control module (HVAC) demand.