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SD1too · 27th March 2020, 14:58

Hello Digby,

This will be coolant loss in the 'V' due to shrinkage of the 'O' rings, particularly that at the base of the thermostat housing.

If you remove the plastic manifold chamber then the LH bank aluminium manifold you'll be able to remove the three plastic coolant components by levering very carefully underneath the fixing flange of the thermostat housing. First though, note the position of the two serrated clips on the straight pipe. Are they touching the water pump and thermostat housings? If so, slide them inwards before attempting to remove anything. The curved pipe is the most fragile of the three and if you're lucky you'll get it out without breakage. New 'O' rings are CDU 3858. There's no need to renew the entire assembly but many people do.

After reassembly, make sure that you slide those serrated clips outwards so that they're hard up against the water pump and thermostat housings. It's this positioning which makes the assembly absolutely rigid and prevents future leakage. Mine's been bone dry for several years now. Take no notice of a well-known and notorious member's efforts to belittle this simple remedy, should he appear on this thread.

Simon

PS 60,000 miles is about right for this problem to occur. There's no need to remove the temperature sender.

27th March 2020, 14:58	#3
SD1too Doesn't do things by halves Rover 75 2.5 Connoisseur Auto (1999) Dealer launch model. Join Date: Mar 2007 Location: Former Middlesex Posts: 20,385 Thanks: 1,587 Thanked 3,749 Times in 3,181 Posts	Hello Digby, This will be coolant loss in the 'V' due to shrinkage of the 'O' rings, particularly that at the base of the thermostat housing. If you remove the plastic manifold chamber then the LH bank aluminium manifold you'll be able to remove the three plastic coolant components by levering very carefully underneath the fixing flange of the thermostat housing. First though, note the position of the two serrated clips on the straight pipe. Are they touching the water pump and thermostat housings? If so, slide them inwards before attempting to remove anything. The curved pipe is the most fragile of the three and if you're lucky you'll get it out without breakage. New 'O' rings are CDU 3858. There's no need to renew the entire assembly but many people do. After reassembly, make sure that you slide those serrated clips outwards so that they're hard up against the water pump and thermostat housings. It's this positioning which makes the assembly absolutely rigid and prevents future leakage. Mine's been bone dry for several years now. Take no notice of a well-known and notorious member's efforts to belittle this simple remedy, should he appear on this thread. Simon PS 60,000 miles is about right for this problem to occur. There's no need to remove the temperature sender. __________________ "Whatever is rightly done, however humble, is noble." Sir Henry Royce. Last edited by SD1too; 27th March 2020 at 15:02..