I have a 97 Silverado w/5.7 Vortec, 124000 miles, I have put 3 new 195 degree and 1- 210 degree thermostats, new water pump and can only get luke warm at best heat inside, from first start up temp will climb to 210 for a few seconds before dropping back to 160 degrees on instrument gauge, laser temp gauge shows close to right temp at thermosat housing and radiator hose. Any ideas?