I have a 2002 2.3L A/C AUTO Ranger with 187,000 miles on it that kept having coolant come out of cap upon shut off. I replaced water pump, thermostat, fan clutch (confirmed bad) . It still would spike to 3/4 way on temp gauge, then fall to half way, even with heat running. I replaced the cap on the overflow tank, still did it. Finally replaced the overflow tank/cap complete and fixed the issue. I have read a lot of threads in regards to this issue. Most guys are saying headgasket. Nobody but 1 guy I found thought to replace the entire tank. Fixed my truck. Owners don't seem to understand that the overflow tank is an extention of the radiator on these 2.3L 2001-2011 2.3L Rangers. Very critical to maintain 16 PSI in this system. Leaking tank was sucking air upon start up and then when it warmed up and I shut it off, the hot air needed to escape. Air escapes easier than coolant and would boil out the cap and super small leak around the cap base. I am here to tell you, this overflow tank is critical. $60 beats a headgasket or radiator replacement!!! Pass this info on to all 2.3L owners who have this same set up. I know the 2001 to 2011 models are the same tank.

 

That seems to be the norm for a quick diagnoses when people don't know what they're talking about.
"Replace the head gasket"...

 

Welcome to the forum

Well, in fairness if you posted overflow tank was "overflowing" then that very well could be head gasket issue.
Only a few might know the 2.3l DOHC engines didn't use an overflow tank system

You have an expansion tank also called degas tank or degas bottle, totally different than overflow tank system
Overflow or recovery tank is not pressurized, coolant expands when heated so some will be sent over to the overflow tank, when engine cools down and coolant shrinks that coolant in the overflow tank will be sucked back in to radiator

Degas system is all pressurized, there is a air volume in the degas tank, as the coolant heats up and expands the air volume shrinks and when pressure reaches Cap Rating some of that air is released, when engine cools down air is sucked back in.
And yes if you had a coolant leak, you would lose coolant and air would be sucked back in as coolant cooled down, so engine would run hotter from less coolant available and you would get air blocks in the head, so temp would go up and then back down as the air block was pushed out.
But EXACTLY the same thing happens with head gasket leak, cylinder with the leak pushes "air" out of the gasket breach and into the cooling system, this air ends up in the head, and this air will collect at a high point and block coolant flow, an air block, so temp gauge climbs, but so does pressure from water pump and the air block is pushed out of the way and coolant flow returns, temp gauge goes back down.

So "overflow tank" plus temp gauge description would point right at head gasket or cracked head


And if the degas "bottle" was spitting out coolant then it could still have been a bad head gasket or cracked head over pressurizing the system.

Glad it was just a leak.
In future a simple Glove Test could have told you head gasket was off the table, or was the cause of the overflow

Ranger V6 engines all use overflow tank system, well all Rangers did until the 2.3l DOHC Duratec :), it was the only one to use degas/expansion tank setup

I don't think one style is better than the other, as long as the degas bottle coolant level can be seen that is, most are semi-transparent plastic so you can see if coolant is low
With overflow tank you can just open cap and look if you can't tell from the side of the tank, even went engine is hot
Degas has pressure when engine is hot so can't remove cap until engine cools down

 

Expansion tank, is what I meant. Your correct in the use of the term. I just couldn't get over how many 2.3L owners don't realize there is no radiator cap. It is the expansion tank cap that IS the radiator cap in essence. I believe this is something people don't think to consider as a potential cause of coolant issues on these models.

 

What is the glove test you speak of?

I ask this only because I have been having a slight coolant leak coming out of the degauss cap for years now. I've replaced the degauss tank for a new one and have replaced the cap multiple times for new oem motorcraft. Yet I still have a slight out gassing of coolant. I know this because if I look at the liner on the inside of the hood I can see where coolant was...

My oil is clean, no milky or cloudiness in it. I also pressure tested the system at 16psi before and it held no problem. I just ordered a uv kit and light and will have that tomorrow to inspect if there are any other leaks but I know it's around the cap of the degauss tank because when I take the cap off I can see dried coolant there...

Thanks,
-Nigel

 

You may be overfilling the system.
If your engine uses an expansion tank, degas system, then tank is not meant to be filled up to the top with coolant.

When you warm up any liquid it will expand, over flow system used full radiator and then allowed coolant to expand OUT of the radiator as it heated up and then to be pulled back IN when coolant cooled off

Expansion tank, degas, leaves a volume of air in the in the system, top of the expansion tank, this allows warm coolant to expand into the tank, at 16psi the cap will allow the AIR to go out of the cap, then on cooled down the AIR is pulled back in.

If you overfill a degas system then coolant will come out of cap because there is no more AIR to come out.


Glove test determines if a cylinder is pumping air into the cooling system, i.e. cracked head or blown head gasket.
This air limits cooling so some overheating will occur, but in a degas setup this air would usually end up at the top of degas bottle and be pushed out vs coolant being pushed out


Glove Test
Cold engine
Remove cap on degas bottle/tank
Place a Latex Glove over cap opening, seal it with rubber band
You can use a balloon or even a condom in place of Latex glove.

Disable spark, unplug coil pack or spark plug wires, you want a No Start
Now crank engine over

If there is a cylinder leak the Glove will Bounce up and down on each compression stroke of that leaking cylinder.

If glove just lays there then no cylinder leak

If glove bounces pull out 1 spark plug at a time and crank engine
When glove stops bouncing last spark plug removed was from the leaking cylinder

 

Excellent explanation! I will be doing this over the weekend.

Yep definitely not over filling the tank. Only filling to the max line which is about half/little bit below the degaus tank.

I found another thread that I bookmarked at work where someone used a 2006 Ranger 2.3L thermostat instead of the heated one that is on the 2001. Apparently the 2006 is rated at 190' F compared to the 220' F of the 2001. The extra heat builds up and pushes the coolant out the top and puts stress on everything. I have to ask questions in that thread when i get to work shortly.

-Nigel

 

I think '01/'02 used the head thermostats , maybe '03

But in any case you can use later model unheated thermostat housing, BUT(big but)...........
Your '01 computer needs to see that heater or CEL(check engine light) will come on and STAY ON FOREVER, lol.
So what many do is to install the later model unit and then plug in the old unit and zap strap it out of the way, this make computer happy and driver happy

Yes what happen on the 2.3l Duratec was the lower rad hose needed a 180deg t-stat, but there wasn't one that Ford could use, so they designed one, but to get it into production took a few years
So they added a heater to the 220deg housing to make it a 180deg(or 190deg), so the change to later model housing won't make it run cooler unless there is a problem with current thermostat unit.
Also much much cheaper for the later model unit, much cheaper, lol.

The way "most" cooling system work is with the thermostat is on the top rad hose, and a radiator can cool about 15 to 20deg.
So if you install a 195deg t-stat on the top hose, then bottom hose coolant will be about 180deg when it comes out the bottom goes back into the engine.

So if you use t-stat on lower hose you want a 180deg so top will be 195deg, 190-200deg coolant temp is what you want at top of the engine for best MPG and engine life, not an opinion, an S.A.E. Study

But there is a problem in that hot coolant rises and the lower rad hose doesn't get much circulation UNTIL thermostat opens, so you need to allow for some circulation on the lower hose so t-stat can heat up and wax can melt, which is why there can be some oddball hoses on engines with thermostats on lower rad hose, lol.

 

Found the thread:
Duratec cooling mods -- Need to clear CEL - Ford Ranger Forum

I'll post what I did there:

I have read everything here. Everytime I drive my truck I smell coolant. I checked and sure enough the top of the under side of the hood cover has been misted by coolant from the degauss rad cap. (I have a 2001 2.3L).

Af first I thought it was the cap so I purchased a new OEM motorcraft one. Still had the same problem. Figured it was the degauss bottle. Bought an OEM Ford and replaced it and then also replaced the cap again for OEM.

I can still see faint traces of where coolant is coming out from the bottom of the cap. Back in 2013 I replaced the thermostat that was original on the truck for an OEM Motorcraft one:


That exactly, which is rated at 190'F.

I have an ultragauge so I can see the engine temp. It ranges from about 190'F to about 215' F. IS this normal? I don't know if that's using the top engine sensor by the spark plugs. That too has been replaced with new many years ago. For whatever reason my old sensor was reading something like 265'F and as soon as I replaced the sensor it read normal readings...etc.

I will note that I fill the coolant bottle to MAX... after reading perhaps that's too much and I should just slightly keep it at above MIN?

There is no other leaks other than where the cap is... I don't believe there is any blockage at all because when I turn on my heater that works perfectly fine and is hot. When the truck is running and I open the hood I can see the top most coolant hose spitting coolant back into the degauss bottle which I am assuming it's circulating as it should. Nothing is boiling. No coolant in the oil either...etc.

See pictures of my drive today going to work. About 35 minutes of highway driving 65mph. Engine temp reads in order from: 199 to 215'F. Is this normal? Shouldn't that read at 190'F because of the thermostat opening at 190'F? Or is it going to be hotter because well... it's the engine?

This is the only thread I could find that remotely covered anything about this.

EDIT: From research it looks like the engine temp is what the sensor is on top of the block via the Engine cylinder head temp sensor.


Thanks,
-Nigel

 

If thermostat is on lower hose of any engine, then upper engine temp will be 15 to 20deg hotter
So 190deg t-stat on lower hose would get 205 to 210deg as normal on upper engine, 215deg is fine.

240deg wouldn't worry me hauling a load or climbing long grade, but 265deg is officially overheating, lol

 

So after I drove today I felt the upper hose and it's hot. The lower hose is much much cooler. Not COLD but definitely cool.... is that normal? I'm trying to read all these different posts on different forums and people are saying if the lower hose is cooler something isn't working right.

I know the hose is definitely not 200 degrees at the bottom... I will confirm this by driving for 30 minutes then pulling into my garage and seeing the temps on the hoses...etc.

I could pull the radiator and see if there is a clog somewhere. I feel like if there was a clog the temperature would go up much higher/faster... no?

No milky oil either.

I don't mind buying a new radiator since I'm sure this one is 17 years old.. But I just don't want to be throwing parts at it if this is normal in terms of temp.

I rented a pressure tester from advanced auto and will test it to see how it holds pressure.

Is it normal to be seeing coolant flowing through back to the degas bottle from the upper right hose. See attached picture.

Thanks,
-Nigel

 

Place your hand on the rad in various places, it should feel warm all over with no cold spots.
This test should be done on a fully warmed up engine.

Cold spots on a rad where the engine is fully warmed up, indicates a partially blocked rad.

The top hose being hot while the bottom one is cool, also says the rad is blocked and or the thermostat isn't opening.
New thermostats should be tested on the stove to make sure they open.
Low coolant can also cause these symptoms.