'94 K1500 Suburban 350/4L60E
I'm still getting a fluctuating temp. gauge. The Tech II at GM says 197
degrees on the ECM sensor, but the gauge still reads high. My local GM
dealer had the truck nearly a week and couldn't find a problem with the
electronics. They, first, diagnosed a bad gauge cluster, but they replaced
that and it wasn't the fix. Then they changed the temp sender for the gauge
(in the head) and that wasn't it. They hooked up my engine to another
truck's gauges and that gauge did the same thing mine was doing.
Upon a cold startup, the temp gauge will progress over to the 250-260 mark
before coming down, then go up and down. Mostly goes up during
acceleration. When cruising at 55 mph constant, it will remain about
180-190 and sit there indefinately.
I had an exhaust gas test on the cooling system done this weekend and it
showed no problems. We, then, tried burping it with a burb funnel and it
didn't do anything. The coolant kept coming up, then down, then up, then
down. We revved the engine to about 1500 RPM, then held it there. When we
let it go back to idle, the coolant gushed out the top of the radiator.
I put a new water pump on yesterday afternoon, just for the heck of it and
it still acts the same. I let it sit overnight without the cap on and had
to add quite a bit of a-frz. this morning to bring it back up to the top.
What does this sound like? I'm stumped!
I've ran both heaters to try to open anything that may have air trapped, but
it doesn't seem to help much. Any other suggestions? This started shortly
after I ran a coolant flush, so that is why I was guessing it was an air