glmoore0001

I was reading Wally Plumley's article on Dexcool on John Pirtle's page and he recommended draining Dexcool (which my car is running), flush with plain water, then flushing with Prestone Heavy Duty cooling system cleaner and another water flush and refilling.
When you flush with water, are you just filling the system with water, running the engine till warm, then draining?
The article states that you should not run Dexcool for more than 5 years and I am trying to set a Time Baseline for the next change.
Thanks... Gary Moore

Mrmerlin

Gary what ever you do dont go flushing the system,
drain it and refill it with your favorite 2 gallons of coolant and 2 gallons of distilled water.
flushing the engine can also make the HGs leak.

I would suggest to use Zerex GO 5 coolant at the next change.

NOTE you can flush the heater core by removing the short hose from the rear of the head and the small hose for the water bridge put the hose in a bucket and add water through the heater control valve till it runs clear into the bucket, add some water into the coolant bottle as well this will drain out into the bucket.
then refit the hoses

glmoore0001

That is exactly what I will do.

Mrmerlin

drain the block as well, each plug holds about 1.2 gallons its messy,
a little kiddie pool makes quick work of all the splashes

GT6ixer

+1 just used one. Works great.

dr bob

So an offline question came up around whether a flush is OK. The history on DexCool is that there was a rash of head-gasket failures attributed to early DexCool. I'm one of those victims, in my case with my early Ford Explorer V6 and some external coolant leaks. Mr Merlin's advice to not flush is aimed at the OP, who was ready to dump a can of heavy-duty cooling system cleaner into the reservoir and let that do some extra cleaning. Not A Good Idea.

Still, you do need to take adequate steps to make sure all the old DexCool is out of the system. A thorough flush with clear water will do the job, so long as you can get good flush water circulation through the block, the radiator, and the heater core. For me, that includes disconnecting the large coolant hoses at the radiator, turning them loose-end-up, and flushing from upper hose through the block drains. Then upper hose connected to radiator with lower still disconnected, flush through the top hose and out the lower hose nozzle. Then connect everything again, fill with water, start and warm-up the engine with temp slider at full hot so the water pump can push water through the core. Then drain everything again. Then drain plugs back in, hoses reconnected, add G-05 coolant and top off with distilled water.

So fresh-water rinse as needed to get all the old coolant out. Any oil in the system deserves a bit of liquid Tide in a rinse cycle.