Hey guys, my coronet has been parked for a few months and I hadn't had any issues with over heating up till that point. Threw a rod through the block on my main ride and was going to use my coronet to get to work this week. This morning on the way to work the engine over heated. Got almost all the way maxed out. I didnt have much choice so limped on down the road at 50mph. This evening I refilled the radiator and about 10 minutes into my trip the gauge went to about 80% From there over the next 5 minutes it got up to 95% and then began to spew. Again I limped on down the road and made it home. Checked the fan and it is running. Upon filling the rad there is no leak spots under the car.
I am trying to determine how likely is it the issue is with the thermostat? The entire engine is covered in fluid and I assume it came out of the safety overflow. Is there a way for me to determine if the issue is a leaky radiator or the thermostat?
If it is the thermostat, how do I change it?
Im driving a 4 door 1967 Coronet 440. The engine is a 318 poly block from a 1965 Dodge box van. I could really use some help and guidance with this.
Pull the dipstick and check the oil. If it's white and foamy, you've most likely popped a head gasket. (better to find this out first I always thought)
If it's clean, fill the radiator and keep cap off. Run engine at a higher idle until it gets warm, and see if you see water suddenly start to flow thru the radiator at a good clip, it means the thermostat opened. If it doesn't, then first thing to do is pull the thermostat, you can either swap it for another one, or check it by putting it in a pot of water on the stove and heating it up. Use a meat thermometer to see what temp it opens up at. (You can also use the themometer when running the motor to see what temp it opens up at).
If the thermostat checks out OK, then it could be the water pump has gone bad (it's rare but seen the impeller come off em before).
With it heating up that quick, I'd lay odds on a stuck thermostat.
Thanks for the quick reply. My first thought was thermostat as well. Oil is clear.
Where is the thermostat located at and how is it removed? A new one is only 6 bucks so easy enough to swap it out.
It's very easy, where the upper hose goes into engine, the thermostat is right there.
1) Drain radiator
2) Remove upper radiator hose where it goes into thermostat housing
3) Remove 2 bolts holding housing down and remove housing.
4) Remove thermostat
5) Clean gasket surfaces
6) Put new thermostat in (spring down)
7) Put housing on with new gasket and tighten bolts
8) Reconnect upper hose
9) Fill radiator and fire it up. Watch for thermostat to open and finish filling radiator.
Is there any reason the house has to be removed?
The thermostat is inside the housing. It's just 2 bolts and off it comes.
Swapped out the thermostat and no joy. I did notice the guage sent down after a few minutes of cruising around 35mph, pretty quickly as a matter of fact. Knowing that, what could it be? Water pump?
Have you noticed if the radiator hoses are collapsing when they get hot? They might need to be replaced. How old is the radiator? It might be plugged up with rust/crud.
I checked this last night and it is not collapsing. I would say the radiator is pretty old. Its not falling apart by any means but lots on it. Is it possible for me to flush this myself or is that something I would need to take to someone? I wish I had someone close by who would be willing to help me learn all this stuff. Never had a dad who took the time and I really enjoy it all but am always frozen in my tracks by fear of not doing something right and or tearing something up. Any way for me to tell if it is the water pump? I found the fact that it only over heats if I get up over 45 fir a bit of time. I imagine I could drive it around all day at lower speeds and it never over heat.
Pour a can of Prestone Flush in it and let it run for about 10/15 mins and then drain it, I would also pull the 2 drain plugs on the block and let that drain too, then stick a hose in the radiator and turn it on and let that run thru it for a few mins, then stick the plugs back in and tighten the pit dangly bits on the radiator and fill with fresh antifreeze. I'm going to do this with my car this spring, the stuffs been in there for about 5-6 years and I'm going to get it changed.