my problem has been going on basically since I bought this truck.

The truck has run well the whole time, with this being the exception .

The dam thing has the overheats . hahaha

I am gonna get a little detailed and drawn out with this, just to describe the issue at hand. Its a 2003 ford ranger, with the 2.3 dual cam 4cyl. The Truck has repeatedly overheated since I have owned it ( only a 2-3 years ). It had 140k miles on it when I got it, and apparently has a replacement (2001)engine in it. So I dont know the actual mileage, or previous/possible problems. I got truck for super cheap and it has still been a great work truck.
Anyway, At first , the temp gauge would shoot up randomly and infrequently. I would check it out and sometimes notice the reservoir exp tank empty and then refill it, seeing that was the problem. Well the temp would stay allright , but if I were to run the a/c for long enough , or just drive long enough , even on the highway , the temp wold climb up and not go down. this was before I removed the Tstat. I was certin it was a tsat problem , as the temp fluctuated out of control.
So the truck would not overheat when driving around town , but then on the highway, after 10-15mins ( everytime) it would start overheating.
no matter how much water/ coolant I had in there it would start to overheat. there were a few times where I drove a long way , some highway , and it didnt overheat . So I kept filling the tank

So this has been going on for like two years . hahaha( not funny)
well it hasnt been two years really . Because a few months ago I went to replace the tstat and just removed the whole thing( internal part) as the housing was like 150 bucks and I didnt have a replacement. well , I thought it was good but then after about 20 mins on the highway it would start overheating .

So all this time I have seen that needle in the read quite a few times, and I have pulled over and let it cool and fill the tank, and it always seem to be empty. I dont know if the tank is blowing it out the cap or it is leaking somewhere else.....eventhough there are no signs of any leak until it sit after running too hot and blows it out the cap . No signs of smoke , no signs of coolant in the oil .

I just dont get it ....

It is driving me nuts. Now , just so you know I have done quite a bit of work on cars and trucks. I have checked and tested the crap out of this trucks cooling system and cant find any conclusive answers.

I sat with this thing and let it idle with the a/c on for an hour, no tsat, and it overheated only after about 45 mins... fans working , water must be circulating( but I dont notice much flow through the tank if that matters(withoutstat)) . while I let it idle I checked the radiator temps with an infrared thermometer. all was normal until about 30 mins and then it would creep up , and then finally get to about 3/4 (215*) on the gauge.
So I have seen the clutch fan not working properly and i am not sure if there is supposed to be a high speed fan that would kick on at high temps, But still I didnt think that was really the problem .
Everytime(almost) I am on the highway, after 15 mins the temp starts going past the half point. I think it has gotten worse lately . more frequent .

It has done this almost since I bought it , and I would like to know if anyone has any suggestions to what I should check or replace next

I think the waterpump is ok- it heats up regularly after start up and doesnt overheat right away.
No tstat in place. ( some say the truck can overheat due to this but I seriously think that is not likely)
electric fan works when called for by temp switch .
Possible faulty reservoir cap , but it doesnt seem to leak until it is way too hot.
it will overheat when driving on the high way .


Anyone have any advice for me ?

I am gonna go drive it and watch it overheat ...

 

I had the same symtoms due to a faulty radiator

 

Plugged radiator or the lower radiator hose is collapsing on the inside (may not be visible on the outside).

 

Thank guys , I was thinking a similar thing
I'm pretty much gonna try anything at this point
Cuz I can't narrow anything down

What are the chances of it being a cracked head , or gasket ????

I filled tank with water and drove highway with success yesterday , temp remained good for 30 mins , crept up a bit , started to overheat once I got off

Im gonna get some new parts and try to get them in there

 

whats your cooland look like, if its like brown that could possibly be part of the problem, especially if it has stuff floating in it, so you could try to flush out the system, i did this by draining it rinsing out the radiator and hoses and running water in for about a week with draining out the water and putting new in every other day and then when it looks better putting new colant in it, also you want to clean out the resivior since that gets build up after a while as well.

A faulty thermostat could also be the issue, if the thermostat isn't reading or reading right the computer will think that the engine isn't hot and not cirrculate the coolant through the engin right.

You could also have a bad water pump thats not pupmping the coolant right.

Even try getting electrical contact cleaner and cleaning the contacts on the mass air flow censor, i've even heard of that causing heat issues, no idea why and my truck is too old to have one to worry about, so i don't.

Hope this helps you out, so you can try the inexpensive fixes before you jump to getting a new radiator.

 

if it was a cracked head or a leaking gasket you would know, and if it was leeking coolant in to the cumbtion chamber you would notice it in the ride