Have Z71 91 Chevy pickup, 350 gas, has weird overheating problem that I have been dealing with for 3 years!, it acts like it has an airlock or something, will peg the gauge or almost peg it, then will come down on it's own or NOT & will have to stop and restart and then it usually comes down. When it gets real hot on the gauge, heater blows lukewarm air, then when gauge moves toward normal temp, heater air gets HOT and sometimes I seem to hear a gurgle in the core??? It has a new thermostat (actually had 3) and I even took the last one out and checked in hot water on stove with thermometer (IT WORKS), replaced the 2 temp sensors, new water pump, a new radiator was put on very first thing as it had a hole in it, BUT when I put on the new radiator they only had radiator in stock that was also equipped for an engine oil cooler and my truck was not equipped for such, would that matter, I hooked up the radiator with no engine oil cooler, should I get an engine oil cooler some how and hook it up to it?