Overheating Issue...

cowboycowboy91 · Jun 22, 2016

My brother has a 1992 ford ranger 4wd with a 4.0L in it. Anyways, it had a bad fuel pump and set a couple years and I got it running about a couple weeks ago. He was driving it yesterday and it started steaming. The temp guage didn't work, so I got a aftermarket guage and slapped in it right quick today and changed the thermostat. I then ran it down the road and back and it heated up to 220. I took off the belt and spun the water pump and it sounded smooth and didn't make any noise when I spun it. The radiator had some junk in it though. I drained and flushed it out with a garden hose and then filled it back up with fresh clean antifreeze mix. What do you guys think I should do next? Change the water pump or radiator? I am thinking it is the water pump, but not sure. While I had the coolant sensor out, I had my brother bump it over and it spurted water out the port. So, its pumping some coolant. What do you think?

RonD · Jun 22, 2016

Feel the upper hose at the radiator after engine is warmed up
Then feel lower hose, should only be 10-15deg cooler, if it is colder then coolant is flowing too slowly thru rad

Pull rad and do a Flip test

cowboycowboy91 · Jun 22, 2016

Re

I used a heat gun and the upper radiator hose was 210 and the lower one I just felt and it was really hot too. Does that mean its not the radiator? Also, what is a flip test? I am sorry, but I'm not sure what that is. I might sound dumb here, but if you just flip the radiator over, how would you fill it? Would the filler spout be on the bottom?

RonD · Jun 23, 2016

Flip test is old school for radiators, like the Glove test is for blown head gaskets.

Pull radiator out
Put rad cap on
Place rad so tubes run up and down, so on it's side
Put hand over lower hose outlet
Fill rad using upper hose outlet, just water, garden hose
Stop filling when full
Remove lower hand
Rad should drain instantly, very fast
Tilt rad a bit to get all water out

Now the test
Flip rad upside down
It any water comes out it could only come from blocked tubes.

cowboycowboy91 · Jun 23, 2016

Re

Thanks Ron! I might try the flip test then and see what happens.

gw33gp · Jun 23, 2016

Just flushing with a garden hose is not a very good flush. It would be much better to flush with a strong chemical flush from a parts store. That should remove build up on the inside surfaces of the block and radiator. Even a thin film of gunk/corrosion on the surface can interfere with thermal conduction and result in overheating.

cowboycowboy91 · Jun 26, 2016

Update

Ok, I want to say whats going on now. I have changed the radiator, water pump, and thermostat. The overheating issue is still happening. The fan clutch seems fine. It runs @ 180 for about 10 to 15 minutes and then starts ticking up as I drive. I drove it about 4 miles and after 3 the temp guage rose to 200 and by the time I got home it was 220. It is a manual temp guage, so I think it is working. Anyways, I am thinking it could possibly be a bad head gasket or cracked head. I have not noticed bubbling in the radiator though, but I did notice that the radiator has considerable pressure build up with the motor being started cold and turned off before warming up. There is no coolant in the oil or any coolant loss that I have noticed. What do you think it could be? Am I down to it being a bad head gasket?

RonD · Jun 26, 2016

4.0l OHV engines also have a weak casting between valve seats and would crack, causing blown head gasket symptoms.

Do the glove test, post #6 here: http://www.therangerstation.com/forums/showthread.php?t=167776

That will tell you if that's the problem or not

Denisefwd93 · Jun 26, 2016

Guys may get tired of hearing me say it but my fan clutch "seemed" ok.. had it changed to HD and it's been golden ever since. they just aren't that expensive either.
jus sayin

cowboycowboy91 · Jun 27, 2016

Update

Hey Ron, thanks for that info on the glove test. That is pretty clever. Also, thanks to the other people who answered. I wanted to update everyone about the glove test info that Ron suggested. I plugged the overflow tube and dropped the antifreeze level to a couple inches below full. I then pulled the fuel pump fuse to prevent starting. The engine was cold. I then put a latex glove and rubber banded it over the radiator. Anyways, hope I did the steps correctly. Then I cranked it over for awhile and the glove didn't move a bit. Not even a puff of air come out. Does that mean the head gaskets and heads are good? If it does, where do I go next? Maybe it is the fan clutch huh? Anyways, just letting you guys know that it passed the glove test.

cowboycowboy91 · Jun 27, 2016

Hey, also I was thinking...is there any way that a port in the water jacket or heads is plugged up causing an overheating issue? If so, what do you recommend me doing? What type of chemical do I need to flush it with and does it actually work? So far, the thermostat housing and water pump was really nasty. The thermostat had actually rusted into 2 pieces. The impellers on the water pump had chunks of rust coming off of them. I think somebody was running water in it at 1 point in time. Probably the previous owner didn't add antifreeze to it through the summer and caused a pile of rusting. Anyways, just wanted to run it past you guys and see if it would be possible to have some rust plugging something in the water jacket up.

RonD · Jun 27, 2016

Yes, good test method, and yes it means heads and gasket are good.

My '94 4.0l had random temp fluctuations, uphill downhill didn't matter, idle or high RPMs, temp would climb up to above 1/2 but less than 3/4, then drop back down to just below 1/2(normal warmed up temp)

It turned out to be the heater core, it was partially plugged.
In '94 and maybe '92? the heater core is the by-pass and part of the cooling system, not an add on that can be shut off.
There is no heat control valve on the heater hoses, so coolant must flow thru heater core when engine is running or you will get overheating issues.

On the plus side, heater core was $25 and you only need to take out 4 screws in the cab and the hose clamps to swap it out, takes about 20min to swap.

In my case it was random up and down of temp gauge, it didn't stay hot, maybe a minute are two up then down for 5 minutes.
And I have to say I did replace a perfectly good fan clutch because of that symptom, lol, learning some times costs a buck or two

cowboycowboy91 · Jun 27, 2016

update

Hey Ron, thanks for that additional info about the heator core being the water pump bypass. I went and bought an 89 cent fitting and bypassed the heater core by connecting the hoses together....just to see if that was it. Good news is it helped, bad news is that it didn't fix it. At highway speeds and driving down the road is fine. I was thinking it was fixed, but I let it set and idle, and it started ticking up again. When I went out and checked it, it was all the way up to 230 degrees. Anyways, maybe the fan clutch is my last option....it isn't leaking silicon or loose though, and it feels firm when you spin it....but it is a thermal fan clutch, maybe it isn't locking up at 1:1 ratio when it should. I am not sure. Anyways, what do you guys think?

Denisefwd93 · Jun 28, 2016

page 1 #9 Now it's the only thing you didn't change EVEN THE HEAVY DUTY FAN CLUCTCH IS under a $100 so whatever

RonD · Jun 28, 2016

Normal temp at highway speeds and climbing temp at low speed or stopped is classic fan clutch failure symptom.

Rad fan takes over air flow under 30mph, above that vehicle speed provides enough air flow.
But it is also outside temp related, lower air flow with cooler air vs higher air flow needed with warmer air

Overheating Issue...

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