Re: New Owner Question
Actually, the temp rise to 224 in slow or stopped traffic and extended idling is perfectly normal. Nothing you have described in any of your posts is abnormal for the operating and temperature conditions described. Absent any airflow through the radiator/over the engine - from either fans or moving - an engine will overheat if left idling at an ambient temperature of 32 degrees much less at 90.
Normal cooling fan sequence with no A/C compressor function set is: Slow or stopped, engine warms to 224, fans go to SLOW. Engine cools to 213, fans turn OFF, cycle repeats. IF ambient temp is so high that the SLOW air movement won't cool the engine, fans go to FAST at 236, temp drops, fans go to SLOW at 224, to OFF at 213.
When you're driving at 15 mph or greater, no A/C compressor function set, fans never run at all. Driving around on nice days with the HVAC system in AUTO is a waste of gasoline, and is unnecessary wear and tear on the compressor and fans.
There's nothing wrong with the Gates thermostat - they're a supplier to AC Delco parts contracts. The DENSO plugs are probably OK, too. The car originally came with DENSO PLatinum plugs installed - look at the specs in your owner's manual. (DENSO now makes the plug under contract to Delco.)
The water pump belt drive tensioner should be quite strong. The tensioner pulley should be dead quiet and smooth in operation. GM no longer recommends the seal tablets - they put out a TSB to this effect back in 2006 or so. They were used for assembly line nuisance weeps, nothing more. If you have leaks, repair them - no tablets.
More diagrams and info in my albums. The Community tab, Albums, the red Seville.
Did you know that your engine is calibrated to run on 87 octane ? Eldorado, slated for extinction, never got the 2000 and later instrument panel.
There's a new design water pump cover and gasket in the field.
Please study the several sticky threads on cooling, fans, and gauges in the Engines, Northstar forum.
Your temp gauge is the older (pre-2000) style but the tick marks correspond to those in this picture. The gauge is heavily damped at the center (12 o'clock) area, so it won't move much from 190 to 210 or so.