We had a bad snow this weekend and I was driving the truck to work and it overheated with lots of smoke. After pulling over and letting it cool down I noticed no holes in hoses and the hoses where warm like things where flowing. I refilled the radiator with anti-freeze but turned off the valve to the heater.

Truck ran fine home and no overheating. I was thinking I dont remember how much anti freeze it had before and might have been too much water and might have cause the heater core to freeze. What is the best way to thaw the heater core?

 

How about a heat gun or blow drier?

 

First off, I'd make sure how much and how strong your antifreeze is. It may not hurt to drain the sytem and refill if it hasn' been done in a while.

As far as thawing out a core, My first thought would be a heated garage, but I know for some (like myself) thats not an option. My next thought would be to get a small space heater (electric) and set it in the cab to warm it up. I'd probably also open up the valve to the heater core and run the engine once things beging to thaw since the hot coolant should really thaw things out once it can start to move through it.

I guess if all else fails try a hair dryer?

Hopefully your core didn't split when it froze, and hopefully your didn't damage your engine either when it overheater.

 

The radiator was pretty empty so I put in 2 jugs of antifreeze. I coasted and cut off the truck once I saw smoke so hopefully it will be okay. It seemed to run fine when going home but not 100%.

Thanks for the heater idea I was thinking about it but was not sure.

 

Just a note here...

...straight antifreeze is just as bad a straight water. You need to mix it down. If I remember right the optimal mix is 60/40 or somewhere around there. There is a chart on the back of the jugs. When in doubt, go for a 50/50 mix.

Bobby

 

Second note:

If you were that low on anti freeze and were in a freezing situation, you might want to check all your freeze plugs to see if you haven't sprung a leak!

 

Another question here, what lead you to believe the heater core was frozen? Just lack of heat? If you were that low on coolant, you may not have had enought to flow into the heater core, which would lead to no heat output. You never mentioned if you reopened the heater valve after you refilled the radiator on your drive home.

Just a thought.

 

Or, (pardon me for saying so - not trying to be obnoxious) if the heater valve was closed in the first place?

 

And are you really talking about smoke, or steam? Steam is bad enough, and is a common sign of overheating, but if you really had smoke, that's an entirely different but equally, if not more so, serious matter.

 

I meant to say steam, sorry for not using the right term. I think the heater core is frozen because it seemed to run really hot with the heater valve open and no heat was coming out of the heater as well. It was in the open position when it overheated.

I was not low on coolant but am pretty sure just more water than antifreeze in the mix. It started snowing friday and I drove the truck home in the snow that night from work. We got roughly 6-8" over the night. Saturday day it was lightly snowing but I started the truck up and warmed it up and it seemed fine. Sunday no snow but colder and I started the truck up and warmed it up with no issues. Monday I warmed the truck up and seemed to be running warm but not bad so thought driving it would cool it down with airflow. That's when it pegged the temp gauge and saw steam so coasted and shut off the truck.

When I put in antifreeze I did check to see if there was any leaks but did not see any. I closed the heater valve and drove home and the truck was at perfect temp and was running great.

This morning I looked under the truck and did not sign of major leaks (heater valve still closed). Started the truck up and let it warm up. Drove it to work which is only 12 minutes away with short highway jaunt. Truck stayed in the middle of the temp gauge and ran fine. Was just curious and testing it since I have roadside assistance ha ha.

Going to pick up a small heater and leave it in the cab for a while then going to open the valve and see if I have luck.

 

Personally, I think you're making this way harder than it needs to be. There should be enough heat radiating through the firewall on these old trucks with an engine up to normal operating temperature to raise the temp in an attached heater box above 32F, which will thaw any frozen water and allow circulation. (it's in excess of 100F under the hood at the exhaust, which is right by the heater) It's more important that you test the level of protection in your rad water with one of those 3 dollar Prestone anti-freeze testers and make sure you're operating safe, and that your coolant level is correct. So open the valve and go for a drive. See if you have heat. Unless you have some other problem, like a leak, a cracked head/block or blown gasket, everything else should take care of itself. At least, that's my 2c.

 

Have you tried to run it with the heater valve open again since you topped off the coolant? I'd give it a shot. And here's why:

It may not have APPEARED to be low on coolant. But the more I hear the more it sounds as though the coolant had been drained and replaced and the engine wasn't heated up enough to allow the thermostat to open and allow the coolant in the radiator to fill the engine - then get topped off. In that case what little coolant got to the top of the engine was immediately diverted to the empty heater (before the thermostat did open) and got trapped because of all the air in the engine wasn't sufficient to push it out of the heater back to the engine. Thus the steam as well.

I'd open the heater valve and drive it around the block for 15 minutes until it's completely warmed up and see what happens - bet all you end up having to do is add about a quart or two more of coolant and it will be fine after that.

 

Thanks guys for the info. Left the truck out in the sun all day and warmed up the truck, cut it off and opened valve. Worked great since with not even a hair of running hot. Heat still is not 100% though seems like half of what it was. Not sure though.

 

That's good news. You may have some sediment/gunk or air trapped in the heater (or at the valve) restricting flow of warm coolant. Or your truck is just running a few degrees cooler. These heaters were not known for being that terribly efficient anyway!

 

You may have had, or still have, an issue with your thermostat. It may have stuck closed for a bit, causing your overheating, and now may be stuck open, which would cause you to run cooler than normal in this weather, and not allowing the heater to pump out the warm air you're used to. As uncomfortable as that is, you have to admit it's better than the alternative. ;-) If you have access to a known good mechanical temp gauge, checking your actual temperature might be a good palce to start.