Impeller tell tale on a 67 v-4

[a70eliminator]

I read the sticky on adding your home brew tell tale, but the question I have is, If the thermostat isn't open due to a cold engine on start up, or a malfunction wouldn't the tell tale stop streaming if pressure tap is off a passage in the block? If so than you would have to diagnose both stat and impeller no?

 

[iwombat]

Re: Impeller tell tale on a 67 v-4

t-stat lets the water OUT of the block when it opens. tell-tale indicates water pressure IN the block, and thus the health of your water pump only.