Aloha guys and gals!
First time owner here, actually only owned my ranger for about 48 hours.

When I test drove the truck everything went smooth, temp gauge was normal and everything seemed fine. (Later on after I purchased it) I took off the radiator cap just to inspect the color of the fluid and see what the level was like. I started to drive home and realized I forgot to put the cap on all the way so I started overheating just as I pulled into my driveway. Spilling coolant everywhere in the engine bay. Boiling overflow box and lots of steam and the temp gauge was in the red.

So... I let her cool down overnight, topped it off with as much coolant as I had and the rest water maybe like 25% water. I also did the whole "burping thing with a funnel and waiting until the thermostat popped(which it did). Also0 put a brand new radiator cap on. It felt good after I filled her up, it felt like all the air was out of the cooling system.
I drove her about 15 miles and she handled very well until I took her up a steeper highway hill at high speeds(45) in 4th gear, and by the time I climbed about a thousand feet up, she started to Overheat again. All my power is there, no white smoke out the tailpipe, no water in oil. Doesn't smoke when hot either just steam from the coolant reservoir and boiling with the temp gauge on red.

I guess I just want to know if anyone has any ideas...
Should I have burped it differently? Did I miss a step?
Could a small amount of air trapped in the cooling system cause it to overheat so high(in the red)?
Would a small amount of water not coolant cause it to run hotter and lead to overheating?
Any thoughts help, Aloha! -Dylan

 

Assuming that there are no leaks anywhere.
The fill procedure is as follows:
Remove cap, fill the rad to the top _ make sure cap is on all the way _ second lock position.

Fill reservoir to the fill line with 50/50 coolant, not water.
Any air in the system will bleed itself off into the plastic expansion tank.
Keep topping the expansion tank to the fill line as needed _ usually 3 drive cycles _ full heat up and cool down.

Liquid expands when it gets hot, so as the coolant expands it is caught in the reservoir.
The rad cap opens to allow the expanding coolant to drain off into the reservoir.

On cool down, the coolant "condenses" drawing the excess coolant that was hot, back into the system.

All this works providing there are no leaks in the system.
If there are no leaks then normal topping up is done through the expansion tank.

About over heating:
Partially blocked rad from poor maintenance, when the engine fully warmed up, with the engine off, move you hand around on the rad and look for cold spots, any cold spot indicates a blockage _ it should be warm all over.

Worn pump _ due to lack of maintenance the steel impeller blades rust off and not enough coolant is moved around in the system (long shot and coolant would appear very rusty).

Blocked internal engine passages. Debris and scale build up inside the engine blocking things off and you get overheating.

Faulty thermostat, but they are designed to fail "open", but easy enough to check on the stove with some boiling water _ compare at the same time with a new one.

Adding water to the system will not cause it to over heat, to answer your question.

When driving, turn the heater on full when it's warmed up, is it hot or lukewarm ?
If it's not hot, then the heater matrix is blocked, if this is so, then you can assume that the rad is also partially blocked and or the engines coolant passages are blocked.


If this was truck, I would drain all the coolant out (with the heater open) and inspect the coolant.
Leave it sit over night in a large bucket or even a few days.
You can see how much rust and sediment there is in the coolant.
Worse case is the coolant will appear vey rusty upon draining and you will notice right away when you drain it when it's in the bucket.

Any history on the truck, did it sit unused for a long period of time ?


Worst case here at 17:34...

 

Well here we go:
NOW my heater won't even work when the engine is running hot and I have the heat on full blast it's just blowing cold air...
also, I stuck my ear up to the top hose where the thermostat is at and I could hear boiling or bubbling
Its running hotter and doesnt seem to find a steady operating temperature.. i.e. the gauge jumps around the NORMAL spot pretty rapidly

 

At this point the reason why the heater is blowing cold air is because there isn't enough coolant in the system. (not because it's plugged)
The bubbling in the top hose tell you this.

Don't run the truck this way, it's little low on water.

Let it cool down enough so when you remove the rad cap you don't get scalded.
Top up the rad with just water for now and add just water to the over flow reservoir.
Fill at least half full, even a bit above.

In the morning, remove the rad cap again and top it up if need be.
Take it for a drive keeping an eye on the temp gauge, with the heater on full.
Should be hot air at this point blowing, if not top up the rad.

IF YOU HAVE TO TOP UP THE RAD WITH A HOT ENGINE USE LOTS OF RAGS AND REMOVE THE CAP VERY SLOWLY _ LET THE RAGS CATCH THE WATER THAT'S GOING TO COME OUT OF THE RAD.

Sounds like your thermostat isn't opening...

If after tomorrows test of adding water and the test drive fails, the next logical thing to do is to test the thermostat as I described earlier.

And the gauge jumping around like that simply indicates that it's low on coolant.
Sometimes there is water getting to the coolant sender and sometimes not, that's why it jumps around _ it's low on water.

 

Why is this happening ???

If the thermostat isn't opening, the coolant can't flow to the rad.
With out flow to the rad, the engine can't get rid of its heat and dissipate it through the rad.

The coolant (water) will then easily reach boiling point.
Once this happens, the oxygen in the water expands and creates air pockets in the system.
The air pockets expand to the point where eventually air pockets develop in the system.
This becomes even worse if the air pockets develop at the water pump impellor blades.
The coolant doesn't get pumped around anymore.

So in your case the lack of flow is what's causing your over heating problem, so the easiest thing to check for is a thermostat that isn't opening.

 

I will add whenever filling any vehicles cooling system it is best to have the heater on which allows the heater control valve if equipped to open making it easier to purge the air from the system.

I also like to use my Lisle radiator funnel kit whenever possible, the design of it makes purging air from the cooling system much easier on most vehicles.

If anyone buys this kit make sure to get the latest model mine is the original old style which I will be replacing soon.

 

So here is my question with thermostat. Which one should I get? The Internet says go with the original but I also see that using another will help it run cooler... Should I go with the one that pops at a cooler temp? Or the original.
Any other tips with burping the system, I seemed to do it all correctly but still have air in the top hose like I heard...

 

It's supposed to have the 195 degree one (with out checking)
Getting a cooler one may help it along, but if the underlying problem isn't directly related to the thermostat not opening, then it will over heat again if the problem isn't corrected, it just may take a little longer with a cooler thermostat.

Try the cooler thermostat, they're not expensive.

Here's how I fill it so no air is trapped when replacing the thermostat.

Remove the top rad hose from the upper thermostat housing and comfortably twist it off to the side. Make sure it's raised up above the rad.
You may want to remove the air intake hose at least to gain access to the clamp on the upper rad hose.
Removing the alternator makes it easier still and it's easy to do, but make sure and disconnect the "Ground" cable on the battery first.

Remove the top aluminum thermostat housing and clean up the mating surfaces.
Put the new and old thermostats in cold water in a dipper on the stove and bring them up to a boil, the cooler one should open first obviously.
If your old one doesn't open at all, then that's your problem.
The original one will open right around when the water begins to bubble if it's a 195 degree one.

When filling, fill from the rad, but leave the thermostat out.
Carefully watch the water level where the thermostat goes in the upper intake manifold.
You want the water level close enough to the edge with out it overflowing to where the bottom end of the thermostat is immersed in coolant.

Place the thermostat in the upper intake manifold, gasket and upper housing _ torque to spec.
Clamp the upper rad hose back onto the housing and continue filling the rad until it will take no more coolant.
Top up the reservoir if need be.
Install the alternator and air intake hose.

NOTE:
Be carful when removing the two small bolts that hold the thermostat housing in place, they can easily be twisted of with too much muscle.
Use penetrating oil and gently break them free, if they start to move add more oil and thread them back in.
Thread them in and out adding penetrating oil until you're confident that they will come out all the way with out twisting off.
The idea is to work as much oil into the threads so they won't twist off.
Use cooper anti seize compound on them when installing the thermostat.