Ok, at the risk (yet again) of sounding stupid, is there any trick or particular consideration in flushing and replacing coolant in a D? I have removed the radiator for repairs (the tank was cracked and it is being repaired with a new core). Draining the radiator has presumably removed most of the coolant (although of course yet here is still some in the block). What should I be doing to remove the rest of the coolant and replacing it when I reinstall the radiator? Is it simply a matter of filling the radiator and then topping up as the motor warms up and circulates the water? Will I need to bleed coolant to eliminate any air pockets, and if so how? ’scuse my ignorance in these matters...
D special: flush and replace coolant
- Thread starter ajaxvte
- Start date
Hello, I would undo the top hose, remove the thermostat, put a hose pipe in the top of the water pump, pack around it with rags, then turn on the water. This will flush out the block.
Best done outside
Best done outside
Have you removed the block coolant jacket drain plug (reasonably inaccessible, under the exhaust manifold; from memory, it has a 21mm hex head)?
With the heater tap open (i.e. setting on full heat) - and with the radiator installed - I usually run mains water through the system (from the header tank) until the outflow from the radiator and block drains run clear; also back-flush through the block drain hole. I then refill the system with plain water and take the car for a run, let it cool for a short while, then drain the water and when it's cool, re-flush and refill with water, repeating this process once or twice more before refilling with coolant. Prior to refilling with coolant, with both drain plugs open and the heater setting on full heat, I blow through the system with compressed air (dusting nozzle on one end of the small hose between the header tank and the top of the radiator - and header cap tank in place) to clear out as much residue as possible.
Maybe others have a better approach?
Chris
With the heater tap open (i.e. setting on full heat) - and with the radiator installed - I usually run mains water through the system (from the header tank) until the outflow from the radiator and block drains run clear; also back-flush through the block drain hole. I then refill the system with plain water and take the car for a run, let it cool for a short while, then drain the water and when it's cool, re-flush and refill with water, repeating this process once or twice more before refilling with coolant. Prior to refilling with coolant, with both drain plugs open and the heater setting on full heat, I blow through the system with compressed air (dusting nozzle on one end of the small hose between the header tank and the top of the radiator - and header cap tank in place) to clear out as much residue as possible.
Maybe others have a better approach?
Chris
After draining coolant, I have cut the foot of a pantyhose (about 15cms) and placed over top radiator outlet with the top hose and worm clamp holding it in place. Always surprised how much scale it collected on periodic inspections.
Thanks yes have adopted the same trick myself and always amazed at how much stuff it collects...
Just to revive this and previous threads on coolant (none of which seem to have reached a consensus), my reading of the very confusing “advice” out there is that for an older car such as a DS there is basically a choice of three: original (non organic acid technology OAT) green, OAT green and hybrid OAT red coolant. There are those that argue that OAT should not be used in cars with seams and welds in older style radiators. Then there are those who argue that HOAT (red - Toyota?) is ok.
I am tempted to go with the HOAT red, principally so that I can tell the difference between coolant and LHM leaks on the garage floor! But only if the advice is that it is ok with the older radiator and mix of cast iron block, alloy head etc in the D. Of course, for the past seven years of ownership I have used regular green coolant, which may or may not have contributed to the seams giving way in my radiator head...
AM
I am tempted to go with the HOAT red, principally so that I can tell the difference between coolant and LHM leaks on the garage floor! But only if the advice is that it is ok with the older radiator and mix of cast iron block, alloy head etc in the D. Of course, for the past seven years of ownership I have used regular green coolant, which may or may not have contributed to the seams giving way in my radiator head...
AM