Chevy S-10 Thermostat

I was changing the cap, rotor and plug wires on my '95 S-10 4x4 4.3 today and noticed antifreeze leaking at the upper hose clamp. So I went and bought new hoses and figured I’d change the thermostat while I was at it.

The gauge normally reads a notch or two below 210, which I figure is normal, it’s supposed to be 195. The S-10 gauge starts at 100 with 210 in the middle and 260 at the end. No other numbers listed.

So I change the thermostat, go for a long test drive and now the gauge reads 3 notches below 210, or one notch above the quarter way mark. It seems like it’s running too cold now. Could the thermostat be faulty? or was I running too hot before? Wondered what someone else thought before I try a different thermostat tomorrow. My other thermostat was about 5 years old and always had consistent temperature. The new one is a Stant.

I replaced the thermostat (195 degree, Stant) on my 2000 Blazer and the temp gauge reading didn’t change (~190 - 200). Is it possible a 160 or 180 degree thermostat was installed?

Ed B.

It is a 195 degree thermostat, Stant #13009. Seems like it’s running about 170 degrees now. Pretty aggravating, it was working fine before I changed it. I guess I’ll try getting a higher priced one tomorrow and hope it works better. Or I could just put the old one back in.

If anyone cares, the thermostat was faulty.
I went back and splurged for a Stant Superstat #45359 heavy duty thermostat for $10.98 (They only have Stants at this place). The other Stant #1309 was $3.98.

Anyway the temperature went right back to normal with the different thermostat.
I’ll be returning the faulty one.
Wish I could get reimbursed for the 2 hours of my time wasted.

This is why whenever I replace a thermostat I check it first, by putting it in a pot of water, and heating it up on a stove top. With a accurate thermometer in the water, I pay close attention to the just start opening temperature, and the fully open temperature.

Its my experience that the Superstat have a larger temperature range between just opening and fully open. I have performed that test with a new standard Stant and new the Superstat in the same pot of water.

I don’t quite understand the larger temperature range. Is that good or bad? The Superstat takes longer to open up fully than the regular Stant?

The Superstat May control temperature to a slightly higher temperature, but it will hold a more stable temperature. where as the standard stat may fluctuate temperature as it opens, and closes. especially on the first open cycle. I have had some cars run better with the cheap o one, and vise versa on others.

Thanks for letting us know how it turned out. I believe I paid around $10 for the thermostat for my Blazer and I thought it was a little expensive at the time. Even though you lost a couple of hours you’re still way ahead of paying a shop to do it.

Ed B.

When I bought the first one, I just asked for a thermostat and took what the guy gave me which turned out to be the cheapest one, didn’t think much about it. I looked them up online later (Advance Auto) and saw they have 3 different price grades of Stant available for my truck. I think I’ll stay away from the lower priced Stants now.

The thermostat I replaced 5 years ago was a cheap one also though and it worked fine. I don’t remember what brand it was but it wasn’t a Stant, it may have been a Duralast or something similar from AutoZone. I remember it was only around 4 bucks.