The Stovebolt Site Forums The Shop Area Engine Shop Running HOT

Hello everyone,
My truck is a 1953 with a 235 engine from a 1957 passenger car.
I have flushed out the motor, had the radiator pressure tested and pulled the water pump. Waterpump impeller seems good and no noise .Everything seems to be ok but I am still runing hot after 7 or 8 minutes while sitting still.
I bought a 4 row aluminium radiator and it's still in the box. I was kind of hoping to keep everything original or at least look original.
My heat riser value does not have a spring on it and the post it rest on above it has broken off. Not sure if that would cause it to run hot. Not even sure if the 4 row aluminium would help it. Also if has a 17 inch 4 blade fan.
Do any of y'all have any ideas of what I should research or try on the running hot part?
Always much appreciated and thank you for any response

Wade Vickery

Can you tell us more about *how* you flushed out the motor? There are a lot of different ways with varying amounts of effectiveness. If you can give us some details, that would be a good place to start offering helpful ideas.

Did you check the thermostat?

Wade, your heat riser valve definitely needs to be repaired.

If your radiator was pressure tested, it's unlikely that you need to use the four row new aluminum one. These engines run perfectly fine at 180 degrees with the factory radiator and 4 blade fan. Leave the new radiator in the box until you figure out exactly why your truck is running hot.

By "running hot" what do you mean? Is water boiling out of the radiator or overflow tube? What is the temperature at the top of the radiator? Water outlet?

I sent you a Private Message. Since you live only a few miles from me, I'd be happy to help you figure out your problem.

This can better be helped in the Engine shop so I've moved it here.

Hi Wade,
The 235 slopes backward significantly and the rear two cylinders get full of "junk" that's hard to flush out. You may have to do what I did...remove the radiator and water pump, drain the engine and pour CLR in there as full as you can safely get it. Let that sit a couple of days, poke around in there with a straightened out coat hanger and try to dislodge as much as possible.

Then there is the fan...the location of it, actually. It may not be sitting in the center of the radiator and for the best possible cooling it needs to be. A fellow here makes an adapter you can use if that is the case.

Then there is the thermostat. A 160 degree thermostat will be fine...please remember the 160 doesn't mean that's the hottest your engine will run...just means that is the coolest it might run.

Finally idling sitting still isn't something your truck is going to enjoy. The engine compartment is small and there isn't a lot of ventilation with the hood closed. With mine (I should add I have A/C) I use a puller SPAL electric fan and a short shaft water pump. The electric fan is my only one and it is thermostatically controlled.

Hope this is helpful. In places like GA or TX it can be pretty hot naturally and at times in slow traffic it isn't easy to keep these running cooler.

I ran some radiator flush thru my engine before I installed it initially. I had not pulled the head or anything, but did take all the casting plugs out and pressure wash inside. The rear plug behind the bell housing was full of gunk even after flushing before pulling the core plugs (see pic). I installed a new water pump and thermostat and it ran without overheating with the original radiator and fan blade for the 100 miles I put on it before the rod bearing went. When I pulled the head for rebuilding the engine, I found one of the coolant passages at the head completely blocked (I think between cylinders 2 and 3). But that didn't seem to affect the temps.

I guess what I'm saying is that you may need to get more aggressive with flushing. The drain plug at the rear of the block is commonly plugged with crud so it won't drain (mine was) and your flush agent would take a long time to get thru that buildup, if it even could.

Thank you everyone. You good folks are awesome and I am amazed at the great information provided.
I am learning alot here.
Stay tunned

Wade Vickery
1953 Chevy Truck

Unless coolant is boiling past the pressure cap, "running hot" is a pretty generic term. A good cooling system will maintain the temperature of the thermostat plus a few degrees, even during extended periods of idling. Every pound of pressure the cap exerts raises the boiling point of the coolant 3 degrees, so a 4 pound cap, for instance, would keep the coolant from boiling below 224 degrees- - - -at sea level. 7 pounds will keep the coolant liquid up to 233. As elevation goes up, the boiling point goes down. In Denver, at 5K feet elevation, water boils at around 200 degrees F. In the Atlanta area, any temp below 200 or so is probably not "too hot"- - - -unless you're losing coolant. A leaky head gasket will pressurize the system and push coolant past the radiator cap, even at temps below boiling.
Jerry

Hey Jon,
I am interested to hear more about your AC. How does it work and what did it take to design it? I started reading about the Spal Electric Fans and that has me thinking.
Is the Spal Electric Fan loud when it kicks on and were there any modifications needed to install it?
There's always something good to learn here.
Cheers
Wade