Block Heaters - What Do They Do?

[Stocker]

Originally Posted by ebry710

Those lower hose heaters, how do they work?

It would seem that the water pump doesn't open until the engine is fluid is warm. I see they are much simpler to install, but does the lower heater still warm the engine water?

Water pumps don't open or close.... maybe you meant thermostat.

Without trying to figure out exactly how the water circulates, I can tell you how well mine worked in sub-teen temps when windshields were icing up every night.

I had an early seventies Dodge maxi-wagon, which has a monstrous interior that took forever to heat up. It had a 318 cid V8. Cold starts resulted in slightly warm air from the vents, immediately..... and quick warm-ups.

My other car at the time was a Triumph GT6 which had a limited coolant capacity. With the vents left in the defrost position, the coolant circulated well enough that the windshield stayed clear, and the heater/defroster blew warm air as soon as the car was started.