I have the coolant drained out of my system and the thermostat removed. I was wanting to do a flush of the entire system but I am not sure I know how to do it with this capless radiator / degas bottle system. I know I could hook a garden hose up to the top of the radiator where the inlet hose is and let it flow out the bottom. But that just gets the radiator. The reason I want to flush is that I saw small black flakes in the coolant and the bottom of the degas bottle. I have no idea what it could be as the coolant is not that old (maybe 1 or 2 years at most). In the past few years I have replaced the degas bottle, water pump, EGR and pretty much all of the hoses (all Ford parts).

The factory manual says the remove the thermostat, and take the thermostat out and just put the housing back on, then flush according the manufacturers instructions. But I am thinking what might be best is to just fill with water and the flush liquid, then come back and drain it all out then refill with 50/50. But does opening the drain on the radiator or removing the lower hose get all of the coolant out of the system?

 

First you should back flush the heater core separately.
Remove heater hoses at engine end or get longer hose of the same size.

Point one hose down at the ground or into a larger bucket, and then use garden hose on the other hose to flush out the core.

Repeat but in the opposite direction

For future reference you would normally warm up the engine and then feel the heater hoses, warmer one would be the IN hose, so after cool down you would flush thru OUT hose to push out any debris that may have come in but couldn't get out because of the smaller tubes in the core, back flush.

If flow thru the core in either direction seems limited
Get some CLR, mix it with hot water and pour it into the core until full, overflows out other hose
Let it sit for 20min and then flush
Repeat as you see fit.


After that you can do what you said, you should use distilled water, because the minerals have been distilled out, it is NOT the same as bottled water which has minerals ADDED
Minerals are Salts and salts promote corrosion

Run the engine as directed, no need to remove thermostat, when radiator starts to heat up thermostat is open, so flush chemical is getting to all the parts
Also set HEAT to HOT, so core gets full flow

Then drain as directed and refill with 50/50

Yes, removing lower rad hose makes draining faster

Use the correct coolant for your year, there are 3 kinds of coolant, silicate(green), OAT (red/pink), HOAT(yellow/gold)
But color is not standardized so look at the label, and look at what you are suppose to use in your year

 

Thanks for the great info!

I'm curious why it is important to flush the heater core first?

I have always just used the regular green Prestone that claims it is for all engines. I wasn't aware that it might require a different type. I just looked it up on rangerstation and it claims it needs the yellow. Can it cause any damage or problem using the green Prestone instead of the yellow motocraft?

 

Heater cores are not used year round, so do not get constant circulation of the corrosion inhibitors like the rest of the cooling system does.

This is why heater cores can get clogged up and also spring a leak because they rusted thru at a spot where debris collected and prevented the corrosion inhibitor from contacting and protecting the metal.

OAT or HOAT can be used together or switched.

Silicate can only be switched from or to HOAT

OAT and HOAT have 5 year change intervals, this is considered "lifetime" by some, lol.

Silicates is 2 year change interval.

I use silicate on my older vehicles because I KNOW I will probably have a coolant leak or some other issue in that 2 years so will have to change or add coolant.
Silicate is cheaper, lol.

On newer vehicles I use HOAT, more expensive but not that much more when you multiply silicate cost by 2.5, i.e. 5 years vs 2 years

As said read the label, color is not standardized

The silicate is the original Green coolant that has been used since the 1930's

OAT was developed as different metals were combined in cooling system, i.e. cast iron blocks and aluminum heads, Organic acid technology(OAT) is good at protecting the different types of metal, where silicates were more for just cast iron engines.

HOAT is Hybrid Organic acid technology, it actually has silicates in it, so best of both really

 

Everything I read said that the green silicate was the old silicate (IAT) coolant. So I assumed that the green prestone coolant was the old IAT. But I noticed their labeling says "5yr/150,000". Like many of the coolants I have looked at, the bottle says nothing about IAT, silicates, OAT, HOAT or anything like that. So I called Prestone and asked them and they said that their green coolant is now OAT and has been for several years. Prestone says that it is a "universal" coolant and can be added to IAT. Of course traditionally they have said do not add OAT to IAT like you said.

Peak still seems to make an IAT, HOAT and OAT antifreezes,

Antifreeze & Coolants | PEAK® Auto

but Prestone only seems to make the "universal".

 

Yes, color is not standardized or "universal", lol

As long as you stick to one kind and do the change at recommended intervals it will be fine.