my 1995 ranger was running just fine then today overheats in five minutesand thens runs at very high rpms,has 2yr old waterpump newtstat dont think head is blown nowater in oil no white smoke no water on the oil cap,i havent check the plugs for water,stated raining no garage,when engine is cold starts runs fine,but when it gets hot its like a train

 

humm guess all these people dont know whats going on with my truck just wanted little insite on problem

 

Can't tell about the runaway rpm's,, unless you have a sticky throttle cable. Are you loosing coolant from the over flow tank, if so, you could have a bad head gasket. Not bad enough to burn coolant, but let cyl pressure into the cooling system, forcing the tank to overflow. And, is it actually getting hot, or is the gauge misreading. Is the tstat, in the right way, and is the radiator clean?

 

no cable is fine just flushed rad and heater core very dirty tstat in right not loosing any overflow yes it get hot then goes full throttle at idle,no water in oil no water on oil cap no leaks sparkplugs not burning fluid next checking water pump its about 3 yr old sum people saying there made cheap and go out fast im stumped

 

well thanks to one person would tried to give some insite on my problem,but i have it running no blown head no bad water pump no plugged heater core or plugged rad or bad tstat,
was bad heat sensor and broken vac line!!
i got this truck in 1995 with 10 miles on it,i am only owner and never been to the shop i do all work,had this ole truck for 20 yrs and only has 140 thousand on it no rust.why buy a new one when it still runs and paid for

 

If the coolant was in bad shape/rusty as you say it was, then the cooling system components & engine coolant surfaces are in question, as old coolant can become acidic & cause all sorts of mischief. Like rust & scale in the block & head blocking coolant flow & heat conductivity, it & cavitation can eat away at the water pump vanes & bubbles in the coolant impedes heat transfer, all further corrupting coolant flow & heat transfer & on & on it goes for a neglected cooling system, so you don't get any attaboys for neglecting your cooling system, thus the question becomes, what do you do, or can you do about it at this point????
You didn't say that you ran a descale product after flushing the system, or what the condition of the cooling system hoses are in, if the cooling fan clutch, belt tensioner are working as they should be, if you replaced or tested the radiator cap, have a CEL lit & if so, what trouble codes are stored, so still lots of unknowns that could be adding to your overheat woes.
SO, if we can get some more info about the vehicle, like which engine, where you are on All past & present due scheduled maintenance replacement items, the forum may be better able to suggest more focused next steps.
The high engine rpm is likely the computer sensing an over heat condition & it having the IAC raise the rpm, to circulate more coolant to try & cool things down again. When it gets to this point, you could try & turn the heat to Max/Fan speed to High speed & it'll help cool things down.
Since the system has recently been flushed, maybe you have a large air bubble trapped/didn't get a good system air burp when you refilled????
To help burp the system, the specified 195 deg Motorcraft thermostat with the air bleed valve design, or one like it is recommended, along with the specified Motorcraft radiator cap.
Raise the front end, or park with the front end up hill, the steeper the better, to make the radiator the cooling system high point.
Top off & mark the coolant tank level with a 50/50 mix of coolant & distilled water & run the fully warmed up engine, with heater temp control on High, for say 30min, to chase any entrapped air back to the top of the radiator. Turn the engine off, leave the hood up, so it'll cool faster & after its fully cooled down, check the coolant reservoir level mark you made, to see if the coolant level has dropped. If it has, the system has burped an air bubble out & topped itself off. So if the reservoir tank is low top it up, if its dry, top it up & repeat until the coolant level doesn't drop anymore & let us know how it goes.