No Heat

[DomsRanger87]

87' Ranger- v6 Temp goes up but I don't get any heat. Thermostat?

 

[RonD]

If temp gauge in dash is showing normal temp range, but heater is blowing cold, or luke warm, then either the heater core is plugged up or the heat control valve on the heater hose in the engine compartment is not working.

If temp gauge in dash is showing below normal after warm up(10min.) then t-stat stuck open could be the issue.

Google: back flush heater core
This is easy to do and free, but you do need to know which heater hose is IN and which is OUT to have it be effective, the warmer hose is IN.
Back flushing the core can restore heat but it is a temporary measure, core tubes are restricted and will it need to be replaced.

Heat control valve can be operated by a cable or a vacuum line, Ford used both, easiest way to test these is to remove one hose and look at the valve flap while you manually operate the valve control.

 

[ab_slack]

Another thought, check coolant level in the radiator.

I can't recall if it was my BII for certain which would be the same as your Ranger more or less, but I recall encountering this on a few different occasions (different vehicles) and the coolant level was low yet circulating thru engine giving normal temperature but coolant wasn't making it into the heater core the got very little heat.

Anyway it is an easy check.

 

[Twister]

If temp gauge in dash is showing normal temp range, but heater is blowing cold, or luke warm, then either the heater core is plugged up or the heat control valve on the heater hose in the engine compartment is not working.

If temp gauge in dash is showing below normal after warm up(10min.) then t-stat stuck open could be the issue.

Google: back flush heater core
This is easy to do and free, but you do need to know which heater hose is IN and which is OUT to have it be effective, the warmer hose is IN.
Back flushing the core can restore heat but it is a temporary measure, core tubes are restricted and will it need to be replaced.

Heat control valve can be operated by a cable or a vacuum line, Ford used both, easiest way to test these is to remove one hose and look at the valve flap while you manually operate the valve control.

Does an 87 have one of those heater control valves? I don't remember seeing on under the hood of my 87.

Sent from my SPH-L900 using Tapatalk

 

[RonD]

My '94 4.0l Ranger doesn't have one, the heater core IS the by-pass for the cooling system, so coolant is flowing thru the core all the time.
Heat inside is controlled by a "blend door" that the dash board heat control opens and closes.

If core gets clogged with this design then engine will get random spikes in temperature.
Not overheat, but temp gauge will go up above normal then drop back to normal with no obvious reason.

Yes, could be air bubble or even the "blend door" if there is no external coolant valve.