One thing I can say about the Ranger. It keeps the old man from getting lazy and laying around there’s always something to fix. Lately the Ranger has been overheating if I set and idle with the air conditioner on and temperature outside in the high 90’s The temperature will climb and start bubbling back into the overflow bottle. Well I know a lot of people will say that that is only normal however this has started in the last few days I’ve had the truck for about a year and have never had it overheat. It could set and idle all day long and never overheat. I checked the antifreeze and it was a little weak. Only floated 2 *****. So I drained the radiator which by the way is less than a year old as are the hoses installed a gallon of new concentrated Prestone and now I am floating 5 *****. I thought I had fixed it but this afternoon I was moving some trash down to the pick up point and the truck idled 5 to 8 minutes with the AC on and 95° outside temperature and it started the climb again.
I caught it before it got really hot and shut it off after about 10 minutes I started it up drove it down the road and it seem to be OK did not overheat as a matter of fact this is been the case every time it has overheated it has always been after idling and I could start driving and it will cool off. I’m kind of at a loss as t what to explore is there someway to tell if the water pump is going bad how about the clutch fan can someone tell me how to check that out the radiator is not dirty and the fan seems to scream up when you start it cold like it always did. I should also add I recently replaced orifice tube and charge the unit with a charging cylinder so it has the exact proper amount and now it is much colder it blows 38 to 40° air so it is really paying off I don’t know if that causes a bigger load on the radiator or not it used to only blow 60° I should also add that I bought the truck in late August last year so I’ll probably never really experienced day after day of 95 to one hundred degree heat until the last few days.
Any help or experience that anyone can add will be greatly appreciated as I remain as always,
stumped Larry

 

I’m no expert but I think the fan just runs off the crank and is always on. At least that’s how it is for my 05.

The reason it only overheats when it idles is probably because there’s no wind passing through your engine bay and under the truck, your water pump isn’t spinning as fast, and same goes for your fan since it’s off the crank.

But your truck shouldn’t overheat when it’s idling, your cooling system isn’t working as good as it SHOULD. I live in Texas and my truck never over heats even in the summer no matter how long it idles.

I’m not an expert on cooling systems but you might want to try doing a flush on your engine block and changing the thermostat before you go changing your water pump as those are cheaper and easier to do.

Since you’ve got new coolant and radiator it’s probly unlikely your cooling jacket is restricting the flow so much that it’s overheating but worth a try before you replace the water pump. But that’s just me.

Goodluck !

 

Sounds like the clutch on your fan may be slipping more than it should.
Read Ron's response in this post about checking fan clutch operation.
https://www.ranger-forums.com/genera...ranger-162274/

 

Well this morning I ran a fluid test on the radiator just like the instruction said got it up to temperature 10 minutes drained about a gallon out put the fluid in the bottle hooked it up to vacuum put it in the radiator two minutes never changed color Except for a little bit of radiator coolant that got sucked up into the test bottle near the end of the test. It’s supposed to turn from blue to yellow if your leaking exhaust into the coollant.
One note however my test fluid is about five years old. I don’t know if that would make a difference or not. Took the tester out let it idle and it started to overheat almost immediately put the water back in the radiator and parked it. I am so frustrated with this damn truck bought it on the cheap did some Metal Work Shot some paint looks good. Then Thr AC went out and the TRANSMISSION. Put in some new seats new windshield brakes tires fixed a whole host of little problems now the truck is not so cheap and just when I get everything fixed and working good this had to happen. I can’t afford to trade it off. I’m old, retired and have little money. Going to try a new thermostat allbeit the one that’s in there is only about six months old. Beyond that I don’t know what the hell to do. Donations would be appreciated...

 

If your clutch fan is slipping I’d think you’d be able to tell if you popped the hood and king of felt how much air the fan is moving around. Just don’t get your finger taken off. If that’s your problem autozone sells a fan clutch/water pump assembly for a little over $100. Since you are overheating only at idle it does sound like your fan is going bad since while your driving air naturally passes through the radiator without much fan needed.

Most expensive things on cars that go out commonly are trannys and ac. ford builds pretty good engines if you maintain them so I’d say your truck should be a little nicer to you after you fix your overheating problem (knock on wood)

 

Big dog I just went out and started the truck up let it come up to temperature 1/2 ways of the gauge and I checked the fan before I started it and after it got up to temperature it’s almost free wheeling I mean I can give it a flip with my finger and it will spin two or three blades before it stops cold and hot. So I think I will try the cheapest fixes first I will get me a fan clutch then a water pump and thermostat then a radiator. I also listen to the fan right after I started it up it used to sound like a 747 taking off but it is not spinning up like that anymore. So here’s hoping the fan clutch is the source of the problem.
larry

 

If your fan isn’t running at idle then there’s no air going through your radiator to pull the heat out of your coolant and eventually your engine. When your driving down the road the wind passes through the radiator like your fan is on. If your truck doesn’t overheat while driving then your cooling system is probably working just fine you just need air flow over your radiator when your at a stop. AKA a fan clutch should get you sittin pretty

 

That's what I was thinking just unscrew it and take the two bolts out of the shroud if I remember correctly.

I just ran another liquid test on the engine and my test fluid stayed bright blue never changed color any at all.
So here's what I'm thinking since it does not do it all the time I let it sit there and idle with the air on for a good 30 minutes and it never got over 155° according to my tester. That's the temperature coming out of the radiator going in and it is about 195°. Since it is intermittent it's got to be either the thermostat or the fan clutch. If the water pump was the problem it would do it all the time. An intermittent head gasket leak would also be pretty rare. Also I could shine the flashlight down in the radiator after i drained it down and I could see a pretty good flow of water coming through the radiator back out the return. Finally since it doesn't overheat when you're running and Cools down if you start running after it gets hot that means the radiator is doing what it supposed to when air is moving through it and the thermostat is open So the only two things that can make it overheat given what we know is either something that shuts off the water flow or something shuts off the airflow. Therefore I will replace both the fan clutch and the thermostat that should solve the problem because that is the only 2 things that can stop the flow of air and water intermittently.
after you all read this feel free to correct me if my logic has gone astray because this is all going to happen tomorrow, Saturday and I would like to know before I do all this work and Tear this thing apart.
thanks in advance,Larry

 

Exactly your cooling system is working like it should internally you just need air flow for the heat exchange. Aka at idle with zero air flow your cooling system is just pumping hot coolant around and just getting hotter and hotter, but when you go down the road you get that heat exchange of cooler air over the radiator whether your fan works or not.

 

This a.m. I installed a new fan clutch did not change the thermostat because I wanted to know which one was the problem. Couldn’t really tell by how hard the old clutch was to turn when I got out it seemed pretty hard even harder than the new one however after I put the new one on I let it sit there in the driveway for the better part of an hour gauge never moved up past a quarter. Also with the engine idling at a steady 850 RPM you could hear the fan speed up and slow down as the radiator began call for cooling. I had never heard it do that before. After about 45 minutes I took it out on the road and drove it over the mountain gauge never move past a quarter of the way up on the way back I stopped at Burger King got a hamburger sat there and ate it in the truck. With the AC on and 94° outside gauge never moved.
so at this point I am calling it fixed...
thanks for all the replies and the suggestions this forum is awesome.
Larry

 

I’d say we knocked this one out the park glad we could save you some $$

best of luck

just a final note when my truck is at operating temperature the needle sits in the very middle, if your thermostat is stuck open it can cool your engine too much and not let it get to operating temp and take forever to warm up. I’m not sure how ur gauge is setup but I would just keep that in mine since you said your gauge was at the 1/4 mark after an hour

 

Thanks for the warning Bigdog73. I just got back from a 25 mile drive and the gauge did get on up toward the center after I drove a while. I’ve got a 180° thermostat in mine not sure what you’re running that might account for running a little low in the gauge but I learned something on this job that I didn’t know after 60 years of wrenching It turns out that was what was throwing me off on my diagnosis. I always thought a fan clutch either worked or it didn’t and it would give you some morning that it was about to go out. Not so with a Ford Ranger. Mine would just randomly stop working and let the fan free wheel then there she would go temperature through the roof. Then it would work for days and never show any problem. I have read several posts on this forum of other owners having or same intermittent overheating problem it might Be v wise to take note and for 30 bucks change that Sucker out. Its an easy job takes about 15 minutes and then you will know for sure. ONE Guy said he has had his truck to three different shops and the dealer and none of them could find what was the matter. I bet he spent way more than 30 bucks.
Thanks to all, LARRY

 

Ron I bet you know the answer to this question.
I put a new fan clutch on my ranger that has been overheating I think you’ve been following the posts?
She’s not overheating anymore but I thought the fan clutch was kinda of an on off thingy but this one acts like my Honda electric fans. When the radiator calls for cooling the fan will increase in speed a little bit maybe a couple hundred RPMs but if that proves not to be enough it will speed up some more another hundred or two RPMs. And yesterday while it was idling on a very hot day the fan would actually cycle on and off as cooling was called for the fan would tighten up a little and run at the increased speed for three or four seconds and then slow back down and it sat there and did this for a long time. This was going on while the engine RPMs were steady at 850. I have got a Motorcraft high dollar clutch. Don’t get me wrong I like it to work that way but is it supposed to. I have never seen that before on a mechanical clutch. I’m just wondering if I’m going to have to replace it again soon or is that how it is supposed to work? Maybe I just wasn’t paying attention for the last 60 years.

Larry

 

That is how it is supposed to work. It is a viscous fan clutch
Here is a You Tube video that explains how it works.
link:

 

Thanks for the update I watch the video and learned that there is an order of model as well as the viscous model in the past I must’ve been looking at the owner off models the ones that just come on or go off. So mine is working as it is supposed to and I am enjoying cool comfort.
Thanks again, Larry

 

Hey RonD
sorry about posting in this thread but it’s been a while since I was on here and I can’t find my thread about the overheating problem I’ve been having.
Hope you remember some of the hoops that I jumped through and thought I had fixed it when I install the new fan was all right for few weeks and then yesterday It went through the roof for no apparent reason and the radiator was down 4 quarts but it was in the overflow bottle. so I went through most of the test again Past the glove test and passed the exhaust gas liquid test.
top radiator hose 22° hotter than bottom radiator hose and I don’t believe there is any such thing as an intermittent water pump am I wrong about that. I can see the water moving through the radiator. Did you find one thing the relatively new thermostat I put it when I looked at it closely with a magnifying glass I saw it was a 198° stat. So I pulled that thing out put it back Together without a stat Refilled it and up she went through the roof Fill the water bottle with hot coolant. let it sit for a couple hours sucked it all back in and empty the bottle. I’m pretty sure the darn thing had a large air bubble because I couldn’t get 2 quarts of my liquid that I lost when I pulled the stat back in the radiator so I put it in the overflow bottle Started up let it bubble for a few minutes drove it down the road and no heating. These darn trucks are the hardest to get the air out I’ve ran into. So my question is is there anyway that it could pass the glove test and the liquid test and still have a blown head gasket or cracked head?
thanks in advance and all replies will be appreciated,
Larry
PS: One other thing; I tried the heater and it worked fine but that heater valve stays open all the time unless you’re on max ac or off. Can a heater malfunction cause it to overheat I don’t think so?