Thread: Did I get the coolant flush process right?

Hi, i didnt see this procedure only the one through the tank, if you want to do a proper job drill out the thermostat's internals and fit it so, fill the system with dedicated flush mixture, go for a 20 min ride(or what's stated on the detergent) , remove the drain plug, flush it through the tank untill a clean flow comes out the drain hole, fit a new thermostat then fill it with 50% OAT mixture and bleed well

when you fill it unclip and lift the tank above the bleed hole untill fluid comes out there, refit partially the screw, put the tank back then start the engine, keep it rev'd above 1500rpm untill no bubbles are coming at the bleed screw then tighten it, top up tank and tighten the cap well, no need to switch on the heater/aircon cos it has nothing to with the coolant flow whatsoever

I just did mine after a rad replacement, I have a Deefer so my filler tank is higher than the bleed but follow the above process EXCEPT have your heater set to hot and turn it on (unsure if on makes a difference though). If you don't have it set to hot you wont flush out the heater matrix and you may end up with an air pocket. The heater works off the coolant so it needs to be open. Air con on the other hand is a different story.

Joe

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It doesnt matter if it's heater or aircon, on a D2 the coolant flow is not affected by the heater/aircon settings whatsoever cos there is permannent flow through the matrix unrestricted, no valve or such thing, maybe on defender it's different but not the case for a D2.

Hi fellipe, welcome to the forum and congratulations on your purchase.

How does the coolant look, do you know if it original or been replaced prior to now? The reason I ask is with the red OAT coolant, I am not a big fan of using hose water to flush as I would not want to risk any remaining afterwards. For me it was always a drain and refill, but with the correct blend of demin water and coolant. Never tap water.

I am sure others are less concerned, but I have seen little to no internal corrosion. I only replaced the water pump at over 350,000 kms (or so) because I wanted to be proactive when I replaced the hoses, thermostat, and radiator. Replaced the radiator as original was that clogged with bugs and seeds in the fins that it was easier to replace than attempt to clean out and did at the same time as upgrading the intercooler.

One tip, be very careful when touching anything that is plastic under the bonnet. The combination of heat and age makes it all very brittle. Very easy to snap the expansion tank return line, and just as easy to snap the nipple where it connects to the radiator. I snapped mine in the process of replacing the radiator.

Originally Posted by sierrafery

It doesnt matter if it's heater or aircon, on a D2 the coolant flow is not affected by the heater/aircon settings whatsoever cos there is permannent flow through the matrix unrestricted, no valve or such thing, maybe on defender it's different but not the case for a D2.

I've read that it's not a good idea to use the drain plug as it's easy to damage it.

So the engine doesn't need to be running?

Originally Posted by DiscoDB

Hi fellipe, welcome to the forum and congratulations on your purchase.

How does the coolant look, do you know if it original or been replaced prior to now? The reason I ask is with the red OAT coolant, I am not a big fan of using hose water to flush as I would not want to risk any remaining afterwards. For me it was always a drain and refill, but with the correct blend of demin water and coolant. Never tap water.

I am sure others are less concerned, but I have seen little to no internal corrosion. I only replaced the water pump at over 350,000 kms (or so) because I wanted to be proactive when I replaced the hoses, thermostat, and radiator. Replaced the radiator as original was that clogged with bugs and seeds in the fins that it was easier to replace than attempt to clean out and did at the same time as upgrading the intercooler.

One tip, be very careful when touching anything that is plastic under the bonnet. The combination of heat and age makes it all very brittle. Very easy to snap the expansion tank return line, and just as easy to snap the nipple where it connects to the radiator. I snapped mine in the process of replacing the radiator.

Thanks for the welcome

I'll check the coolant later, not sure if it's still original or not. Thanks for the tips!!

Originally Posted by fellipe

I've read that it's not a good idea to use the drain plug as it's easy to damage it.

So the engine doesn't need to be running?

According to RAVE no need for engine running when you flush it but it can help to do it faster... the drain plug removal is part of the official method, you need only a new washer, if you want all the dirt out you need to open the lowest point IMO, about risking to damage the drain plug .... it's valid for any bolt but seems too paranoid for me to not touch it, i've removed mine several times without probs