Low Coolant Temp

sc4808 · February 20, 2008

I Have a 2003 Sierra with the 4.3L V6, it's got 140K on it and has been one of the best trucks I've ever owned. Last week a problem popped up that I have yet to figure out. I got a check engine light and when I checked the code it was "low coolant temprature", now the first thing that popped in my head was the thermostat so I promptly replaced it, no change, after resetting the check engine light it came back on again after about 20 miles.

Then I was thinking that it must be the temprature sending unit, so I went to the parts store and found out that there are seperate sending units for the computer and the guage and since my guage is reading low as well what are the odds that both sending units are bad, slim to none I would think, so it must be something else, but what, I have been racking my brain and have not come up with anything. Some folfs are saying that there is only one CTS and that the parts guy is wrong, if this is true then the sending unit is probably the problem.

As I said above, I have the 4.3L V6 not a V8.

By the way my guage is reading around 170 to 180 degrees, its hard to tell with the factory guage, but it is definately lower than it has ever been before.

And by the way, I live in the south and the temp for the last week has been in the 60's and 70's.

Any Ideas?

redvett · February 21, 2008

Replace the thermostat and before installing it make sure to put in pot of water with a thermometer and make sure the thermo opens at 195F. Not 160 or 180F. The cheap one are junk.