A/C stopped working and no reading on coolant temperature guage.
Thread Starter
New Member
Joined: 06-05-2016
Posts: 10
From: New York
A/C stopped working and no reading on coolant temperature guage.
Has anyone experienced this problem. My A/C stopped working on the way to work on Friday morning, it came back on half way home Friday afternoon. On Sunday (6/5/16) it cut out again, but this time I noticed the water temperature guage is flat lined, and the digital readout is blank also. I can only assume that these two problems are related. Has anyone experience the same problem, and have the remedy for this? I appreciate it. Retired ASE Mechanic here.
to the forums!!
Administrator
Joined: 10-13-2011
Posts: 40,069
From: Welland,Ont Canada
Welcome to the site, if you get the code read it will most likely be P0128, which indicates the thermostat has failed mostly due to age!
Here is a fine how to fix it thread.
We highly recommend you use an AC Delco thermostat and only Dexcool
https://www.chevyhhr.net/forums/how-...l-p0128-24493/
Here is a fine how to fix it thread.
We highly recommend you use an AC Delco thermostat and only Dexcool
https://www.chevyhhr.net/forums/how-...l-p0128-24493/
Moderator
Joined: 01-23-2009
Posts: 26,523
From: Fredericksburg,VA
Retired before 1995, the year OBDii came into universal use?
The purpose of the t-stat is to keep the engine over 180F. The engine needs to be above 180F to operate efficiently (emissions). If the temperature is not above 180F fast enough the OBDii sets a P0128 code and shuts off the A/C and temp gauge in an attempt to get the driver to investigate.
The t-stat on these cars typically fail "open" making the coolant temp too cool. Or the coolant temp sensor is malfunctioning.
The purpose of the t-stat is to keep the engine over 180F. The engine needs to be above 180F to operate efficiently (emissions). If the temperature is not above 180F fast enough the OBDii sets a P0128 code and shuts off the A/C and temp gauge in an attempt to get the driver to investigate.
The t-stat on these cars typically fail "open" making the coolant temp too cool. Or the coolant temp sensor is malfunctioning.
Thread Starter
New Member
Joined: 06-05-2016
Posts: 10
From: New York
RJ, definitely narrowed it down to a bad stat. Who would have thunk it? But watching the digital gauge for a while, it never goes over 185 anymore. It routinely used to hit 212. Now unfortunately, I had tried switching the A/C relay first, and I must have messed something up, because now I have tripped the check engine light! My remote start doesn't work either since then. So, I will have to have the codes cleared as well as changing the thermostat. Thanks again RJ, have a great day.