2005 Chevy Equinox Engine temperature drops

LULUHALEY

MEMBER
2005 CHEVROLET EQUINOX
4 CYL
AWD
AUTOMATIC
65,000 MILES

My 2005 chevy equinox, AWD 3.4L engine, has a P0128 code. I have has the thermostat and Engine coolant temperature sensor replaced. I have had the radiator flushed and filled with dex-cool antifreeze. The engine runs and the temperature gauge drops down to cold and the heat turns cool whenever I start driving over 30mph. After driving on the expressway for 20 minutes the engine was still cool enough to touch. The repair shop can't find anything wrong but I cannot pass the emissions test. Any ideas or suggestions of what the problem could be?

1 Reply

CARADIODOC

MECHANIC
33,867 POSTS

I've been told multiple times that new thermostats are just as likely to fail as old ones. According to one manufacturer trainer, "we not only sell you parts; we sell them to you pre-broken".

Try pinching the upper radiator hose for a few minutes. If the temperature comes up to normal, try another thermostat. On some engines, there is a rubber gasket around the outer edge of the flange. Be sure that is in place. If you have a cap on the radiator, watch the coolant start to flow when the engine is started. There should be no flow until the engine is up to proper temperature.

Caradiodoc