Thanks for the feedback. The Eldo I have has 54000 original miles. Engine cooling has always acted "funny". Never actually overheating, but running hotter then any other vehicle I have owned. Not getting excited about this after doing some investigating. Any way, decided out of the blue to pull the hollow bolt, found red silicone on the end. Now the purge line has always been hot, but I have always felt a gurgling in the top hose. Best of my knowledge, the bolt has never been removed. Now prior to this the engine temp as viewed on the DIC would wander. In traffic the temp would want to go up to the fan turn on point, and then cycle up and down based on fan operation. Once back down the road, engine temp was slow to respond to air flow across the radiator. So now, cleaned the red silicone from the end of the bolt. Reinstalled, filled system
with coolant and headed done the road. Now the engine comes up to operating temp noticeably faster. Gets to about 197 degrees around town and holds the temp without the wandering that it used to do. Now on the highway temp goes to 199 degrees and stays there. No temp wandering on the highway either. Seems more likely that head gasket failure is probably a result of all things listed here, not just the fault of one component in the cooling system. Based on the info read here, I have a few years and a few more miles before I might have to consider TIMESERT work on this engine. Thanks again.