Maybe my searching is bad, but i would have thought someone would have thrown a guide up for this, what with the service manual essentially being unavailable for people.

Does anyone have any tips for flushing, i guess more specifically for the bleeding part?
Normally when i've done this, there has been a bleed valve, or something/somewhere to do in order to let the air out, is this not the case for the Ranger? (specifically the 3.0)

Thanks.

 

Air rises in a liquid so best place to bleed out air is a high spot on the engine side of the cooling system, rad cap is a high spot but thermostat can prevent release of air to radiator.
So usually heater hoses are the best place
Loosen and remove one heater hose at its highest place
Fill system until heater hose has coolant in it then reattach

You can buy a fitting, like a "T" with a removable cap on it, to install on a heater hose so you can bleed or fill system by removing the cap.
Although its a bit much to spend money on something like that since you shouldn't have to bleed system that much, if you do then there is another problem.

Some 3.0l engines had a pre-heater on the throttle body, two smaller coolant hoses that circulated coolant around throttle opening to prevent icing in colder climates, these would be a high point and one could be removed to let air out as system fills.
BUT(big but), the ports on these could break off easily so be very very careful.

You just need to get out "most" of the air, enough to prevent an "air dam", the cooling system is Self Purging, any cooling system is if there is an Overflow tank

After coolant in the engine warms up thermostat opens and coolant starts to flow to radiator
Any air will make its way to the top of the radiator and stay there.

Warm coolant expands so creates a Pressure inside the cooling system
Rad cap is usually rated for 14psi pressure
When pressure gets to 15psi the larger valve in the rad cap is pushed open
If there is any air in the rad the air will be pushed out to the Overflow tank first, and bubble up and out, then warm coolant flows out until pressure is below 14psi
After engine is shut off the coolant cools down and shrinks back to original volume, when it gets below 0psi in rad the Smaller Valve in the rad cap opens and pulls coolant from THE BOTTOM of the Overflow tank back in to radiator, keeping the rad topped up with coolant, no air

Very simple system and works very well

 

That's good info to know, at least, about the lack of Ford designing it fully, at least we can work around it to some extend, thanks!

I'm curious on the PSI rating of the cap, i could have sworn my cap states 15PSI on it, and i *think* it's a factory cap....

I'm thinking that if i can lift the front on ramps about 8 inches, i should get away without needing to remove the heater hoses?

When flushing, i've seen some people say fill entire system with regular water, i'm not sure i need to do that, but i do want to get the heater core along with the block emptied of old coolant as i'm switching from green to yellow (if i can confirm the right yellow, there are several part numbers it seems)

 

Cap pressure can be 12 to 18psi depending on vehicle, 14psi was just an example

Raising the front will work IF(big if) your thermostat has a "jiggle valve"(yes that is what it is called) on the plate and it was positioned at 12:00 when installed.

Picture here: https://s25.postimg.org/4kjiul3mn/ch...-stat.03_a.jpg

Just a hole in the plate with a metal bar that lets air out when refilling engine, metal bar "jiggles" to keep hole open and free from debris.

If you don't have that then air will be trapped in the engine.
If you are unsure then after filling up the system, on the ramps, start engine with rad cap off
Let engine idle until rad coolant feels warm at the top, thermostat is open, takes 4 to 5 minutes usually, and then top it up and put cap on.

Have Cab heat set to HOT of course, when flushing, refilling or topping up, fan can be off


It is not normal to have an air bleeder on systems with overflow tanks since they are self purging, systems that use degas bottles/tanks often have bleeders

 

Ok, i wondered if it was an example pressure, just checking.

Never knew it was called a jiggle valve, nice :) Not sure why this won't work if you don't have one though? I'm assuming aligned to 12:00 would be jiggle valve to the front of the vehicle?

Sounds like on the ramps is just going to help generally then?

OK, big question now then; because of the thermo, i'm assuming that the only way to drain the heater and block, is if that's open, or removed? I haven't looked at the thermo placement on this engine yet, is it easy to remove for flushing?

Just ordered the gold coolant, so i really need the green cleared out completely, and the only method i've seen is run with water after draining, but surely that'll leave water in those other areas?

Thanks for the help so far, very useful.

 

No, the coolant weights much more than the air so will drain out for the most part, some will always remain behind but not really an issue.
When refilling the air will get stuck in pockets and can't get out, jiggle valve is one less place for it to get trapped, heater hose is another

Taste your tap water, if you can taste it then use distilled water as base for flush.
Not "bottle water", distilled water.
Filtered water is also NOT the same as distilled water

Most water has minerals, and minerals are salts for the most part.
This shortens the life of coolants.
Distilling gives you just water, no minerals

 

We're in a soft water area, but i don't think that's what you're asking, i'm going to boil the water first to help.

I'm curious if you think raising the rear would help draining the back of the engine and the heater core?

 

Boiling doesn't help "treat" water for cooling systems, it helps your Health by killing germs in the water.
Distilled water is boiled BUT........the steam from the boiling water is captured cooled and drips into another container(thats the distilling process), so everything but the H2O is left behind in the first container, pure H2O ends up in second container, well pure enough, lol.

Yes, if you angle the truck down hill more coolant will drain out.
But you simply can not drain all the coolant out without disassembling the engine, so not sure what the point would be.

Coolant "wears out" but doesn't "go bad", draining out old coolant and refilling with new coolant brings PH up above 9 and all is well.

You should reverse the heater hose lines at the firewall at each coolant change, this "back flushes" the core for longer life, you should do that after draining but before flushing.

Flushing is not needed unless coolant change has been neglected for many years, like 10 years if you had Red(OAT) coolant, 6 years for Green(Silicate) coolant.
Won't hurt either.

On older vehicles, 15+ years old, it is often better to switch to the Green(silicate) coolant, it is less expensive and needs to be changed every two years.
But the reasoning behind is that a 15 + year old vehicle will get coolant leaks or failed cooling system parts, so the 2 year change is optimistic, you will usually have to drain the system before that and replace some or all of the coolant, so less expensive for the same protection makes more CENTS, lol.

Green, Red or Gold/Yellow coolant has same protection from overheating, freezing and anti corrosion, the Red and Gold just last longer, so better for new/newer cars/trucks

 

It's a 2002 with full service history, but nothing mentions a coolant change.
Gold concentrate ordered already.

I think I need to make sure the system isn't getting air from a gasket failure, no good reason to think it is, just a feeling right now due to the few inches low in the rad and the tank being seemingly plain water.

 

Simple free test for head gasket leak is the Glove test

Cold engine
Remove rad cap
Remove overflow hose, use vacuum cap or gum or putty to cover this opening in rad
Put latex glove over rad cap opening, or a balloon or even a condom
Use a rubber band to seal glove to rad cap opening
So you now have a sealed cooling system

Unplug the coil pack's 4 wire connector, you want a No Start

Crank engine while watching the glove
It should just lay there no movement, if so head gasket is good, no leaks

If Glove bounces then you do indeed have a head gasket leak or a cracked head
Remove 1 spark plug at a time and crank engine
When glove stops bouncing the last spark plug removed was from the cylinder with the leak
Reinstall that spark plug to confirm

Glove test is better than block test, and more definitive, old school is some times better than "new" school



Check the overflow hose and tank for blockage
Blow into the overflow hose to make sure it isn't blocked and doesn't have any leaks
Lower its end below level of tank and it will drain the tank, then flush tank with water to clean out any debris that may clog the flow back to rad as engine cools down
Low coolant level in rad could be clogged overflow, or failing rad cap(smaller valve).
But you would usually notice upper rad hose looks collapsed, sucked in, but not always.
After refill run engine for a few days, a few heat ups and cool downs
Cold engine, check that rad is full to the top, should be FULL to the TOP no air at all
Mark level in overflow tank, do not add coolant to tank
Drive for a few more days
Cold engine, check level in tank
If it is lower then you have a leak, pin hole usually if there is no coolant residue on the ground.
Very hard to find these since they only leak when engine is warmed up and the leaking hot coolant evaporates before dripping to the ground
Best method is to rent a Cooling system pressure tester
It is a hand pump with rad cap fitting and a gauge
You can pump up Cold engine pressure to say 20psi
Then look for a leak, or watch pressure to see if there IS a leak in the engine/rad part of system

 

*That* is the one I saw and couldn't find, thank you :)

It'll be good to run this test before I blow 50 bucks of coolant through the system.

Not really on topic, but is there anything I should consider re HT leads etc? They look like an inefficient design from the 80s.

 

HT leads?

 

Here was me wondering why the thread died, only to realise my post didn't appear (stupid mobile posting with poor signal....

Anyway, HT leads, sorry, ignition leads, i'm English

 

Spark plug wires should be changed every 15 years or so, if Motorcraft brand.

Check with local Ford Dealers for sales on tune up parts, they usually run spark plug and spark plug wire sales a couple of times a year, cheaper than discount brands in most cases.

 

Hmm, that's not a bad idea, thanks.

I did the glove test last night, all good, which makes me happy, i'll go ahead with the drain later this week when the coolant arrives.