Thread: I need some ideas on 350 S/B "Over Heating"

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Originally Posted by cffisher

Just a question. Is the top of your engine higher than the top of your radiator?? If so the engine will get air locked. I'd check the thermostate and maybe flush the engine. Your not realy getting to hot but it is a situation that should be checked. How hot dose it get after you turn it off? You could run the engine with a hose in the radiator and the drain open and see how hot it gets. Over heating problems can be a pain but can be solved. When you changed the water pump you didn't perchance get one for a serpintine belt set up did you??? Sounds like a nice ride you'll get it figured out in time.

Thanks for your ideas. I think I will remove the thermostat as a test and might install one of the "hole" flow restricters in its place as a diagnostic test. On the 1932 Ford with a 350 engine the top of the radiator tank and inlet is much higher than the top of the engine. I will run the engine with the drain open and a hose into the radiator top to flush out the system and check on the amount of coolant flow. I will run a water hose into the top hose (with thermostat removed) to check flow through the block. It sucks getting water on a bare steel frame and steel body, not to mention all of the polished stainless and chrome suspension parts. But I have to get to the bottom of this problem.

Interesting question about the possibllity of having a serpintine water pump? Do they look the same? I thought they were used only on the very late model engines. The pump on there currently is you basic swap meet (imported I'm sure) polished aluminum S/B Chevy pump. I might also take the pump off the engine to inspect the water pump impeller for damage, or that it's turning in the correct direction. This pump was on the engine when I bought it so I don't have much background on it.

Thanks again
John Palmer

John, a couple of more tidbits based upon experience:

The water pumps (regular rotation and serpentine rotation) look the same from the outside. The impeller is twisted the opposite way to account for the reverse rotation.

You can also have a wrong way fan. Symptoms of such are great cooling at idle (air is going out the front of the radiator) and sucky cooling at speed (air coming thru the radiator conflicts with fan pushing air forward). This is a bear to figure out....speed up and it gets hotter, stop and it cools off)

Some temperature senders are smaller threads than the tapped hole in the head so people use a reducing bushing to compensate. Some reducing bushings are made so that the copper tip of the sensor is shielded by the bushing itself and allows a pocket of air to be trapped around the copper tip. The result is usually a significant gauge offset but who knows what else it does. If you use a bushing to adapt the sender, look at how the thing presents the copper tip to the water.

Using sealant or teflon tape on the sender threads can insulate the sender and either make it not work or make the resistance higher, again causing an offset.

As one of the other guys said, the gurgling can be caused by air pockets. One of the older troubleshooting methods to see if there was a head gasket leak was to look at the radiator water to see if bubbles were coming up thru the water.

The engine code TYZ is listed as a 75-77 350 truck motor.

I have never tried running a SBC with the heater inlet/outlet plugged....I have only run a bypass hose between them....someone else reading this may
have a comment on that one.

Lastly, are you running a good thermostat? There are two designs that have been discussed on CHR in the past. The el cheapo has specific problems that I forget what the details are......anyone?

mike in tucson