1996 Ranger with no heat

[chief]

My ranger will not, well some times, blows a little heat. I have had the thermostat changed, and checked the antifreeze. The truck runs at normal operating temp until I turn on the heater and then the temp gauge bottoms out. The heater hose feels warm and so does the core. I would appreciate any help. Thanks - Freezing in TN

[1saxman]

The heater hose should be at 200 degrees, way too hot to hold. Replace the radiator cap. Check the coolant surge tank every morning after use the previous day to see if coolant needs to be added. I believe your cooling system has air in it from a non-functioning radiator cap. Coolant is simply not getting to the heater core. It could also be something as simple as a cracked hose from the rad to the surge tank.

[chief]

I have now replaced the thermostat, the radiator cap, the heater relay switch, and added antifreeze lost in the swith change. Still cold air, dang it! Any of you folk know of anything else to try or is it time to give up and take it in? I hate to do that.

[791ton]

take the cap off and let it run at idle. watch for air bubbles in the radiator. This is known as burping the system. Also watch for the water level to drop when the thermostat opens.

[Bull]

I had the same problem on my 97 F150, I finally found the problem was the water pump. It didn't leak but after replacing everything else I changed it and the blades on it were worn out.

[1saxman]

Originally Posted by Bull

I had the same problem on my 97 F150, I finally found the problem was the water pump. It didn't leak but after replacing everything else I changed it and the blades on it were worn out.

Good call - I forgot about that. Cavitation actually erodes the impeller blades away. Doesn't this usually make the engine run hot?

[Bull]

Mine didn't run to hot, it was at the top of the nornal range but the impeller was worn so bad it looked like a skill saw blade

[btooling]

My 99 Ranger starter the same problem, I did the same things that you did. I may be off in left feild but, my problems plaged me for 6 months off and on until, the Head gasket blew. I personally belive that my gasket was slowly leaking compresson back into the coolant system untill it finally blew completely out. One indication was that my antifreeze would turn rusty prematurly, and It would lose water and never suck it back from the resevoir. Like I say, just a thought, I would check for excessive moisture from the tailpipe. I am a "have to be mechanic" rebuilt the heads, reinstalled and in 50 miles it spun a rear main. In the middle of a total overhaul at present. Heck You have to take the darn engine almost completley out just to get the oil pan off. This may help you head off a major failure and a major amount of time. Hope so.

btooling