How do you guys flush your radiator at home?

 

1. Run a commercial flush for the rated time on that bottle. Let engine cool.

2. Drain into suitable container below lower hose and dispose of properly - antifreeze is toxic to pets, small children (as well as a drowning hazard in something as innocent as a 5 gallon pail).

3. Remove upper, lower hoses and return line to coolant bottle. DO NOT remove any lines on lower sections of "sub" radiators, which are transmission and engine oil (if equipped) coolers. Be careful how much stress you appply to remove hoses, nipples require a tender touch. Cracking the outlet nipple means new radiator usually. Layout attached.

4. Wrap rag around garden hose and insert in lower hose inlet. Be careful not to stress this plastic part unless you want to buy a new radiator. If available, rag and a second hose or short piece of hose in top rad outlet, to direct water away from vehicle. Tape or hold finger over end or small hose on the return nipple.

5. This is reverse flush, to bring out flakes if possible. Turn on water hose to good flow - but not wide open, and observe what comes out, may see flakes of grey looking scale, etc. 30 minutes running time, so plan for where water will go. It will also have some coolant/cleaner residue, but highly diluted. Not a good idea for SHMBO to see this going into "her" flower bed.

6. Connect lower hose back. Insert garden hose and rang in upper radiator beck and fill with plain water, leave hose running at modest rate. Crank truck and allow coolant/cleaner to be flushed from cooling system, until it runs clear. Again, may want hose to direct water out of top hose away from truck. Antifreeze does not like paint.

7. Detach lower hose and drain plain water.

8. Attach all hoses, double check fittings. Refill with 50/50 mix of coolant and distilled water. Use green or yellow coolant, NOT Dexcool. Distilled water inhibits calcium forming inside radiator tubes. System capacity (dry) is 13.1 quarts. So if you only put in like 1.5 gallons you are not done yet. Follow established procedure for venting / purging / burping using the delicate fitting for that purpose.

9. After test run, recheck coolant level in jug, and re-check every day for a week, then back to just weekly check (along with other fluids).

10. D1 owners the same, just four hoses (extra return line from throttle body heater). D1 owners can apply garden hose thru top fitting is desired with hardware store adapter. Pix below. This does alter the threads of the fill hole somewhat, so may want to use a plain hose end sprayer and rag wrapped around it. I long ago re-did mine for 1/2 inch NPT.

11. IMHO drain of removing block drains is optional, as you are also flushing engine in steps above.

 

Agreed

Couldn't help myself....but serious great post. I've been meaning to do this!

 

One more step to the flush, once you have all the old coolant out, run 2 or 34 gallons thru to remove as much of the tap water from your radiator, if you skip this step, you will build up more calcium in the radiator plugging it up, then you get to buy a new radiator.
When finishing, install Peak coolant, not Dexcool and add a bottle of Water Wetter or Purple Ice to help your coolant system .

 

When flushing mine, I remove the driver's side block plug (passenger side is impossible to get to) and dran from the engine additionally. Also, being extremely **** about the residual tap water in the block, hoses, etc, I use my shop vac/leaf blower to blow out the engine and hoses. I then refill with 50/50 premix Peak universal since I don't feel like buying distilled water and mixing it myself.

 

Drain coolant.
Fill with garden hose.
Idle with heater on for 15 min.
Let cool for 15 min.
Drain.
Refill.
Repeat until all water comes out clear.
Refill with your favorite all aluminum safe coolant, I prefer the 50/50 premixed because it is idiot proof.

 

3. Remove upper, lower hoses and return line to coolant bottle. DO NOT remove any lines on lower sections of "sub" radiators, which are transmission and engine oil (if equipped) coolers. Be careful how much stress you appply to remove hoses, nipples require a tender touch. Cracking the outlet nipple means new radiator usually. Layout attached.


Does this mean all upper and lower hoses connected to radiator including removing thermostat at this time or just unplug right at radiator connection? also is coolant bottle, do you mean expansion tank? Now when running engine for 15 mins with hose in ( Im guessing by this Insert garden hose and rang in upper radiator beck and fill with plain water you meant plug hose into upper radiator hose opening into radiator? and the coolant and mostly water will go all over the place since you don't have a sealed system at the moment?

 

Yes sir, I mean all hoses that attach to the main radiator, at the radiator. And I would stuff the water hose with a rag in the lower water inlet, because we want to reverse flush. You might want to do the same at the top to keep water from going where you don't want it. Reverse flush has a good chance of breaking loose scale. Not very effective in block due to water pump, etc. But I would run for like 10 minutes after it becomes clear, more may come loose. If you have hot water to use, even better, there is a hose bib on most water heaters....

If using a commercial flush, like Prestone, that requires running in the vehicle with cooling system closed. But GM has a TSB for dexcool flush that has you run car for like 3 hours.... then remove and flush out, neutralize, etc. If your goal is dexcool removal, it will take longer than 15 minutes. TSB attached.

And yes, the coolant recovery system fixture, jug, bottle, white thing, it is an important part of the system.

And don't forget the heater core. On a D1 it is only used when the heat is dialed on. On a D2 it is running coolant all the time, and that path is very important when thermostat is closed. As you know the D2 has a remote thermostat. It depends of hot coolant entering four small metering holes on the top hose connection (flow direction is down). This heats up the stat to open. There is minimal flow thru the closed stat, and part of that flow goes thru the heater core. Block up the heater core with gunk, and it will take longer for coolant to circulate enough to heat up stat and coax it to open. Meanwhile the engine is warmer than you might want.

 

Thanks !!This is great! I have another question too since this is slightly a complicated cooling system... outside of using a real gauge, is there a way to test the system while sealed to know if it is cooling correctly already? my disco II never goes above 1/2 mark or below.. just sits there... of course heats up quickly to temp but just with all the fear of hearing them overheat I just want to make sure... I know my lower radiator hose stays cool to touch for at least 5 minutes at idle but I understand something about idle not a good test since it doesn't open up or something like that? I get decent overflow back into expansion tank and I think thats a good sign and heater and A/C work properly.... I just have some weird feeling after driving for some time it might be a little hot but don't really know where to tell... my ultra gauge should arrive soon and that can help for sure! I need a manual temp gauge! lol

 

Please see this posts and all attachments. https://landroverforums.com/forum/di...ed-help-45372/ You are wise to not trust the gauge. Above 9:00 it considers truck to be overheating, no matter what dad's F150 did. Testing cooling system with scanner or ultra gauge lets you see what is going on degree by degree. Stat is fully open at 204 F. So IMHO, that should not happen when you are cruisning down the road at 50 mph on level ground with no trailer. The system should have some "reserve" capacity. A plugged thermostat (metering holes, a restricted heater core (less water flow when stat is closed, which is needed to bring hot coolant to the remote stat), a restricted radiator (dexcool sludge, bottom of radiator wil be colder (more than 20 degrees) than top rows, all these things can add up. My D1 runs 194 -196F at 50 mph.