AndrewGS
Newbie
My father got a "new" '99 Suburban K1500 LT with 170K miles on it a couple of weeks ago. I noticed after we got it home, which was a 200 mile drive, that it was running extremely cool. We checked the fuel economy and it was bad, 14MPG pretty much all highway, so I think it was running in open loop the whole trip. I cranked up the heater to see if it was actually getting warm but it blew lukewarm, so I knew it wasn't the sensor.
Tonight we installed a new 195º thermostat, but it seemed to warm up to the point it was at before and stopped. I cranked up the front and rear heat and it started to warm up a bit, consequently the heat got hot good and hot like it's supposed to. It finally warmed up enough to open the thermostat and it cooled back down a little before closing and warming back up. After idling a while and driving around it seemed to hold steady.
Here is where it was sitting before I cranked up the heat and it began to rise:
Here is where it warmed up to and settled after a while:
What is the normal operating temp on these engines? What temp does the ECM go into closed loop?
Tonight we installed a new 195º thermostat, but it seemed to warm up to the point it was at before and stopped. I cranked up the front and rear heat and it started to warm up a bit, consequently the heat got hot good and hot like it's supposed to. It finally warmed up enough to open the thermostat and it cooled back down a little before closing and warming back up. After idling a while and driving around it seemed to hold steady.
Here is where it was sitting before I cranked up the heat and it began to rise:
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Here is where it warmed up to and settled after a while:
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What is the normal operating temp on these engines? What temp does the ECM go into closed loop?