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Overheating 1977 Toyota Pick Up

Just bought this truck with the fantasy of restoring it, but sadly it overheats before I can even drive it to the parts store. I have already pulled the thermostat. There seems to be something weird with the reservoir/ radiator. The res was empty, but the radiator was overfull when I went to go check if coolant was circulating. It also appeared as though the coolant was not moving. I checked that both the bottom and the top of the rad were heating up, so don’t think its the radiator itself. There was a new water pump put in by the previous owners, but that still seems like a likely culprit. There is no indication of internal system leakage. Any thoughts? Thanks!

Yup.
You could have a collapsed, hose inner lining, or a clogged radiator. My money is on the radiator. Your radiator cap might be bad too, allowing the hot coolant to push out of the radiator when it expands and not allowing the contracting, cooling coolant to draw more back in from the reservoir.

You planned on restoring this pickup. It’d help greatly to learn how the various systems work.

Has it been sitting for a long time? I would do a good flush on it replace the T-sat with a fail safe type. Check to make sure the fan / fans are working. Also a check the hose’s. A soft hose could block the flow. Oh and don’t some of these guys talk you out of restoring it. Have fun and post some pics.

Does it REALLY overheat (boils over) or is it just the gauge that is signaling an overheat condition?? The gauge may be lying…

With the thermostat out, remove the upper radiator hose from the radiator, point it aside and start the engine. It should shoot coolant 20 feet…Oh, you have fresh coolant? Aim the hose in a bucket to recover it. This will verify pump operation…

Thanks oldbodyman. The cap is good, flushed the system and it was still running hot, but coolant was circulating better. Might try the water pump next…

And yes. It is very boiling.

Since you flushed the system and it seem to circulating better, that would tend to make me more suspicious of the radiator.