Chevrolet Repair: hot engine, tap water, mineral content

Question
i have a 93 s-10 tahoe blazer, when i drive for a wile the the check gages light comes on i look at panel and temp gage is way up there( hot )then it go's back to Normal the guy i bought it from had replaced the Thermostat,and i Wonder if maybe it is the water pump, took off the cap and ran engin nothen for awile then girgeled over the opening so thought it had Circulation ?

Answer
Hello Don,

Water pump is a possibility.

Or the thermostat could be in wrong, or just not working.

Or, there could just be air trapped in the system. Sometimes it is hard to get it all out when refilling.

The radiator tube condition is another possibility. They could be plugged.

I would remove the thermostat, and fill the system with water, and just see if the water pump produces flow. With the thermostat in place it is hard to tell till it opens, but without the thermostat, you can see immediately.

When you decide, and replace whatever is needed, I use antifreeze and distilled water, rather than tap water, but that all depends on the mineral content of your tap water.

Good luck,
Van