New stat...same problem

Hey guys, I posted a while back about an overheating problem. My 89 Suburban was purchased in the spring. It warms and idles fine but at speeds of 40mph+,
even while cruising, it will jump in temp from 180-190 to 260+. It stays maxed for a few secs then returns to normal operating temp. It'll stay at that temp for a few secs then jump all the way up again. This temp jump stops at red lights etc. and the engine idles just fine. I have overflow of coolent, but just a little at a time. I changed the stat to a Stant 190 degree and have the same issues. Now, I noticed some crud, like a twist tie, for example, in the coolant resevoir when I added coolant the first time. Could something be pluging the water pump or radiator? And how the f*** would someone get a twist-tie ing with the coolant.
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it sounds more like the wire to the temp sender is shorting against the block or exhaust
if it doesn't overheat at idle at lights, when airflow and water pump efficiency is lowest, I doubt there is a REAL problem
as for the 'stuff' in the coolant reservoir, who knows ?

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snipped-for-privacy@aol.com says...

Similar problem, looked in the archives and found a couple of questions but no answers: 91 S10 Tahoe Pickup, warms & idles fine, on acceleration the "Check Gages" light comes on and the temp gage pins at max for a second or two, then drops back down to operating temp. Very little coolant overflow, and this ONLY happens when accelerating in gear, does NOT happen in neutral or park.
Thermostat? Temp Sensor? something more sinister and evil?
Thanks
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Check for a collapsing lower radiator hose.~~~Ed

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I second that recomendation.. I had a 64 Valiant once, couldn't figure out what was maiking it overheat on the road. It would run just fine idling all day in 100 degree weather. Didn't fix it until I noticed one day that when I reved the engine at the carb, I noticed a movement in front of the radiator. Did it again and noticed the lower radiator hose collapsing. Removed it and saw that the spring that is supposed to keep it from collapsing was rusted away. New hose no problem. KenG DesertEd wrote:

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