The 75 and ZT Owners Club Forums - View Single Post - The Function and Malfunction of the Diesel Thermostat

Mike Noc · 20th January 2012, 20:56

Probably due to the difference in the pipe diameters of the two circuits.

The second valve will bleed off excess pressure when the coolant is only flowing through the smaller heater matrix pipes, and allow full pump flow when coolant is flowing through the larger radiator pipes.

Mike

20th January 2012, 20:56	#9
Mike Noc This is my second home Rover 75 CDT Manual Connoisseur SE, Rover 75 CDT Automatic Connoisseur SE & a Freelander Td4. Join Date: Jul 2009 Location: Hampshire Posts: 11,570 Thanks: 3,470 Thanked 3,119 Times in 2,247 Posts	Probably due to the difference in the pipe diameters of the two circuits. The second valve will bleed off excess pressure when the coolant is only flowing through the smaller heater matrix pipes, and allow full pump flow when coolant is flowing through the larger radiator pipes. Mike Last edited by Mike Noc; 20th January 2012 at 20:59..