Recently when doing a reasonably thorough coolant flush, (305TPI) I noticed when I took out the knock sensor and the drain plug on the left side of the block, that both holes were so blocked up with gunk, nothing flowed out until I poked a screwdriver in to dislodge it all then the old coolant came pouring out. I didn't touch the coolant sensor for the gauge but was wondering, could it too be all gunked up in the same way and if so would that make it so the gauge takes longer to show the actual temperature?
Just trying to figure out if my car actually takes as long as the gauge says to get to temp or if the sensor is faulty or doesn't have direct contact with coolant due to being gunked up ?

 

That sending unit is in fairly intimate contact with the head casting, so it shouldn't matter as much, if at all.

 

Would you think there's any reason to replace one aside from it being 32 years old ?

 

Sludge usually collects at the bottom - like it does in the overflow bottle - & it can't really 'settle' in the head like it can at the bottom of the block. As long as it's working;Temp gauge sending unit should be fine !