John
#1
08-13-2018
Join Date: Aug 2018
Location: Oroville CA
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#2
08-13-2018
Welcome John
I also have 1994 4.0l Ranger, 400k now, been a very good truck
1994 was last year of the 60 wire EEC-IV Computers, OBD1 system
1995 and up Ranger used 104 wire EEC-V computers, OBD2 system
NEVER overheat the 4.0l OHV engine, pull over at the first sign of rising temp gauge, and let it cool down
4.0l OHV heads have a weak/thin casting in the heads between the valve seats, if head gets too hot it will crack there and you will need a new head or two.
So check over cooling system regularly
Heater core also has a tendency to clog up which can cause temp gauge to go up and down, reverse the heater hoses at the firewall every 2 years, when you change coolant.............
Heater cores on these are very easy to change, 4 screws and two hose clamps, and not expensive
So if heater output is not HOT then swap out the core
I also have 1994 4.0l Ranger, 400k now, been a very good truck
1994 was last year of the 60 wire EEC-IV Computers, OBD1 system
1995 and up Ranger used 104 wire EEC-V computers, OBD2 system
NEVER overheat the 4.0l OHV engine, pull over at the first sign of rising temp gauge, and let it cool down
4.0l OHV heads have a weak/thin casting in the heads between the valve seats, if head gets too hot it will crack there and you will need a new head or two.
So check over cooling system regularly
Heater core also has a tendency to clog up which can cause temp gauge to go up and down, reverse the heater hoses at the firewall every 2 years, when you change coolant.............
Heater cores on these are very easy to change, 4 screws and two hose clamps, and not expensive
So if heater output is not HOT then swap out the core
#3
08-13-2018
Join Date: Aug 2018
Location: Oroville CA
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Thanks for the info
hey thank you for that bit of information I hope I can ask a few more things? I think my temp gauge must be messed up or not working correctly cause it never says more than half way but the other day it was running terrible so I pulled over to check I cracked the radiator cap it seemed to not be spraying water so I went ahead and opened all the way, big mistake it went everywhere burnt me a lil but that told me that she was very very hot? I think but the gauge never showed hot at all. Is there a way to test the gauge to see if it’s good or what should I do next? Thinking of removing thermostat due to I don’t have any money rite now but still need to get around. And thank you for any info you can help me with?
#4
08-13-2018
Ford temp gauge has about 210degF as 1/2 way mark
You have a 190-195degF thermostat
So temp gauge should show just below 1/2 way after full warm up, but above 1/3
And if hauling a load or driving up a longer hill then it can go just above 1/2, that is normal, 3/4 would be PULL OVER TIME
After about 10 minutes of running there should be 10-14psi pressure in the cooling system, that's the rating of the rad cap, so what happened would be expected if engine was warmed up, not a sign of any problem, there should be pressure in the system after driving it.
This pressure comes from coolant EXPANDING when heated, all fluids expand when heated, thats how a Pressure Cooker works
Your 1994 and most Rangers(except 2.3l duratec) use an Overflow cooling system.
It will have an overflow tank with a COLD line and a HOT line, this overflow tank is NOT sealed for a good reason, it needs air flow
This system is Self Purging for air inside engine or radiator
When engine is COLD open rad cap and have a look at it, it has TWO valves, larger valve has the big spring, it holds radiator closed until 14psi pressure is reached and it is then pushed up and allows hot coolant to flow out of radiator and into Overflow tank, until pressure is lower than 14psi when it closes again.
This coolant that leaves the radiator raises the level in the overflow tank and can go as high as HOT line but unless you are hauling a load or driving up a long grade it will usually stay just below HOT line
After you shut off the engine, coolant will start to cool down and SHRINK in volume, it takes longer to cool down that to heat up, lol.
But coolant will eventually shrink enough so there is -1psi in the radiator, and this is where the SECOND VALVE in the rad cap comes into play, it is in the center of the larger valve and has a smaller spring.
The -1psi PULLS OPEN this smaller valve and sucks coolant back into radiator from the overflow tank.
After full cool down Overflow tank should have coolant level exactly at the COLD line, if its below COLD line then you probably have a coolant leak
Self Purging of air
Air is lighter than coolant so will collect at any high spots in the cooling system, highest spot is the top of the radiator
So as the water pump circulates coolant and any air, the air will end up at the top of the radiator by the rad cap opening
As engine gets warmed up and pressure gets above 14psi then rad cap opens and the AIR goes out FIRST to the overflow tank.
This is why Overflow tanks hose comes in at the BOTTOM of the overflow tank.
This air goes thru the hose then Bubbles UP to top of overflow tank, and is Purged.
When engine cools down again COOLANT is sucked back in to replace the air that was pushed out on warm up
Very simple and reliable system if everything is working
To check if it is working as it should
COLD engine
Open rad cap and top up radiator if coolant is low, if its not low, coolant at the very top, then system is working as it should, but test it anyway, lol.
Replace cap
Make sure overflow tank coolant is at COLD Line, if hard to see it then add your own mark, tape works
Drive for 20minutes or more
Check coolant level in overflow tank, should be higher now
Wait until engine is cold again and open rad cap, coolant should be at the very top, no air at all
And coolant level in overflow tank should be at COLD line or the mark you made
If so then all is well
You have a 190-195degF thermostat
So temp gauge should show just below 1/2 way after full warm up, but above 1/3
And if hauling a load or driving up a longer hill then it can go just above 1/2, that is normal, 3/4 would be PULL OVER TIME
After about 10 minutes of running there should be 10-14psi pressure in the cooling system, that's the rating of the rad cap, so what happened would be expected if engine was warmed up, not a sign of any problem, there should be pressure in the system after driving it.
This pressure comes from coolant EXPANDING when heated, all fluids expand when heated, thats how a Pressure Cooker works
Your 1994 and most Rangers(except 2.3l duratec) use an Overflow cooling system.
It will have an overflow tank with a COLD line and a HOT line, this overflow tank is NOT sealed for a good reason, it needs air flow
This system is Self Purging for air inside engine or radiator
When engine is COLD open rad cap and have a look at it, it has TWO valves, larger valve has the big spring, it holds radiator closed until 14psi pressure is reached and it is then pushed up and allows hot coolant to flow out of radiator and into Overflow tank, until pressure is lower than 14psi when it closes again.
This coolant that leaves the radiator raises the level in the overflow tank and can go as high as HOT line but unless you are hauling a load or driving up a long grade it will usually stay just below HOT line
After you shut off the engine, coolant will start to cool down and SHRINK in volume, it takes longer to cool down that to heat up, lol.
But coolant will eventually shrink enough so there is -1psi in the radiator, and this is where the SECOND VALVE in the rad cap comes into play, it is in the center of the larger valve and has a smaller spring.
The -1psi PULLS OPEN this smaller valve and sucks coolant back into radiator from the overflow tank.
After full cool down Overflow tank should have coolant level exactly at the COLD line, if its below COLD line then you probably have a coolant leak
Self Purging of air
Air is lighter than coolant so will collect at any high spots in the cooling system, highest spot is the top of the radiator
So as the water pump circulates coolant and any air, the air will end up at the top of the radiator by the rad cap opening
As engine gets warmed up and pressure gets above 14psi then rad cap opens and the AIR goes out FIRST to the overflow tank.
This is why Overflow tanks hose comes in at the BOTTOM of the overflow tank.
This air goes thru the hose then Bubbles UP to top of overflow tank, and is Purged.
When engine cools down again COOLANT is sucked back in to replace the air that was pushed out on warm up
Very simple and reliable system if everything is working
To check if it is working as it should
COLD engine
Open rad cap and top up radiator if coolant is low, if its not low, coolant at the very top, then system is working as it should, but test it anyway, lol.
Replace cap
Make sure overflow tank coolant is at COLD Line, if hard to see it then add your own mark, tape works
Drive for 20minutes or more
Check coolant level in overflow tank, should be higher now
Wait until engine is cold again and open rad cap, coolant should be at the very top, no air at all
And coolant level in overflow tank should be at COLD line or the mark you made
If so then all is well
Last edited by RonD; 08-13-2018 at 11:57 AM.
#5
08-13-2018
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Location: Oroville CA
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Thank you I think I have bigger prob
so anyway thank you so much for that info very well explained. So I went out and took cap off rad. Apparently some time ago either me or the wife put the wrong coolant in the truck I think cause I pulled the upper rad hose and all I see is a rust looking color crap like mud in the line and I unscrewed what looks to be a rad drain at the bottom left side if facing the truck and more mudd looking crap so I put the hose in rad and pumped out a ton of mud water now I’m to the lower hose I guess I’m not sure how to clean all of that and how far it is? I imagine it’s prob everywhere in the system that sucks cause it looks hard to get out and it didn’t rinse out with water. But good news is the gauge works fine after your explanation on how the gauge is supposed to work that’s how it works I just always thought why would ford make a gauge that didn’t go all the way up but it’s prob generic for a bunch of fords. Ok one more thing since my system is obviously plugged up would that cause tons of performance issues also cause I don’t want to try and fix that issue if the cause is obviously the Coolant system just curious if it will cause truck to seem like it runs lean or do you think that is a separate issue and I’ll deal with that after I clean all the other stuff out. And thanks againman you are the best help I could find anywhere
#7
08-16-2018
Remove rad cap and ONE heater hose at the firewall, and then remove lower rad hose and drain cold engine
While engine is draining have garden hose on, but lower flow, not high pressure, and hold it against detached heater hose, and then to heater core nipple where it was attached, flushes out core and hoses
Also remove overflow hose from rad cap opening and remove the hose from its clips until the end of the hose is lower than coolant overflow tank(reservoir)
Put running garden hose in overflow tank and let it fill up, then remove it, water should be flowing out the smaller hose, let tank drain and repeat, try spraying water inside the tank to clean it it out
Put lower rad hose back on and refill cooling system with water via rad cap opening
Fill until water comes out detached heater hose and heater core, then reattach hose to core
Put rad cap back on
Reattach overflow tank hose to rad cap opening
Fill overflow tank to COLD LINE
Drive it this way for 1 or two days then repeat one more time.
Yes you can add a suds free cleaner like simple green to the FIRST flush, but use just plain water on the second flush
Water is not always just "water", many areas have "hard water" lots of minerals in it, minerals are SALTS!!!
And most people know what salted roads do to the outside of a vehicle, lol,...........well salts will do the same thing to the inside as well
So if you live in an area with hard water then use Distilled water to refill both times, you can use garden hose water to clean it out
Distill water is NOT bottled water, minerals are ADDED to bottled water
Distilled water is just plain water
Refill the 3rd time with 50/50 GREEN coolant, it is silicate based, 2 year life, don't use red/pink it is Organic based
You can use yellow/gold coolant, its a Hybrid silicate/organic, 5 year life, but IMO it is a was of money once a vehicle gets past 15 years old to use expensive coolant, you will lose a water pump, thermostat or hose will blow out within the 2 years, lol, certainly within the 5 years, so changing every 2 years is a non-issue IMO
While engine is draining have garden hose on, but lower flow, not high pressure, and hold it against detached heater hose, and then to heater core nipple where it was attached, flushes out core and hoses
Also remove overflow hose from rad cap opening and remove the hose from its clips until the end of the hose is lower than coolant overflow tank(reservoir)
Put running garden hose in overflow tank and let it fill up, then remove it, water should be flowing out the smaller hose, let tank drain and repeat, try spraying water inside the tank to clean it it out
Put lower rad hose back on and refill cooling system with water via rad cap opening
Fill until water comes out detached heater hose and heater core, then reattach hose to core
Put rad cap back on
Reattach overflow tank hose to rad cap opening
Fill overflow tank to COLD LINE
Drive it this way for 1 or two days then repeat one more time.
Yes you can add a suds free cleaner like simple green to the FIRST flush, but use just plain water on the second flush
Water is not always just "water", many areas have "hard water" lots of minerals in it, minerals are SALTS!!!
And most people know what salted roads do to the outside of a vehicle, lol,...........well salts will do the same thing to the inside as well
So if you live in an area with hard water then use Distilled water to refill both times, you can use garden hose water to clean it out
Distill water is NOT bottled water, minerals are ADDED to bottled water
Distilled water is just plain water
Refill the 3rd time with 50/50 GREEN coolant, it is silicate based, 2 year life, don't use red/pink it is Organic based
You can use yellow/gold coolant, its a Hybrid silicate/organic, 5 year life, but IMO it is a was of money once a vehicle gets past 15 years old to use expensive coolant, you will lose a water pump, thermostat or hose will blow out within the 2 years, lol, certainly within the 5 years, so changing every 2 years is a non-issue IMO
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