Hi,

The weather has turned colder over the past few days and I have noticed that the temp of my heater never gets "hot" - it seems to old just take the chill out of the air. Today its about 35 degrees out and the temp gauge never gets above N (in Normal) on my 25 mile trip to work.

A week or so ago it over heated because the previous owner had wired the electric cooling fan wrong. I was able to refill it imediatly and fixed the fan wiring that eve.

So... could the over-heat have nackered the thermostat or the heatercore? I don't remember if the heater was ever any good (only had the truck 10 days). Are they prone to airlocks in the heater matrix or do they self bleed?

I'm going to get a new thermostat so see if that helps but how well do your heaters work - I know there is a great variation in temperatures in the States but I would expect it to be as warm as a hand dryer in a Restroom when it has warmed up???

Cold and Frustrated!

Simon

 

Typically, the heaters in the Broncos are quite efficient. I have (for no other reason than I was curious) run around in 20 degree weather in shirtsleeves in my own. If the over heat purged a lot of coolant, you may need to check the level again at the radiator not the expansion tank. If the level in the radiator drops enough, the system will not draw from the expansion tank and you will end up an almost full exapnsion tank and a system full of air pockets. If topping it off doesn't help, try starting with a cold engine and leaving the radiator cap off while you let it idle. This should allow the system to purge any air pockets and you can then top off once it has reached operating temp.

 

when I checked before the level seemed ok at the rad cap - but I will certainly try running it without the cap to see if that purges any remaining air out.

 

Worst case scenario, you've got a clogged heater core. They are pretty simple to replace if needs be.

 

Yeah, that might be true too. I could probably clean it out with a caustic cleaner to remove limescale and scum.... Are they typically copper/ brass or aluminium?

 

I knew you were gonna ask that... I think they are typically aluminum especially on the late models.

 

ah bugger, Caustic cleaner is no good then it'll eat the whole lot away! LOL

 

if i recall the heater cores arnt to spendy. I am gonna do this as well becaue mine just doesnt seem hot enough. I also need to adjust the heater control cables to make sure they are working

 

We just replaced the thermostat in son in law's F150 for the exact same reason. All was fine until he sprung a leak and ran the truck a bit hot. Fixed that and it seemed fine until cold weather hit and he complained of getting no heat. New thermostat and all was toasty again. (Though I still don't think he comprehends exactly what it is the "TEMP" gauge readings actually mean)
Apparently sometimes running an engine hot can toast a thermostat. I've had it happen to me once or twice too.

 

Yeah overheating will ruin the "temper" in the spring and change the temperature "value" required to make the thermostat open. One way around running the risk of this problem is with a "wax core" thermostat. The thermostat is just as the name would imply, a wax of sorts is encased in the t-stat and when the proper temp is reached the wax melts allowing the t-stat to open. Nice thing is, if the truck does overheat, the wax just stays melted. The additional heat won't affect the spring temper as there is no spring to malfunction. When everything cools down the wax solidifies again and the process starts over.

 

Changed the thermostat today and so far it looks like it has cured the problem. On the driveway it warmed up just fine although I wonder if there still maybe air in the system as the level kept changing alot. WIll let you know how I get on when I drive it.

Simon