On one of my B's I have an issue so posting up this thread in the vain hope that someone will respond and try to help me out. 1998 1.8 x18xe automatic. The engine on startup and standing still on tickover takes a long time for the temp gauge to get up to the 90 degree mark. I have checked the temp on OPCOM and the gauge is reasonably accurate to within a few degrees. On driving off to an average speed of 50mph the temp gauge falls to a needle's width above the top blue cold mark. Stopping the car and allowing the engine to get back up to around the 90 degree mark takes about 8 mins. Also I have noticed that when the temp gauge drops to near the blue mark, the cabin heater output falls to slightly warm even with the heat setting at maximum. Sounds like a classic case of thermostat failure doesn't it? In the past 4 months I have changed the original Vauxhall stat (92 deg) with another genuine VX one and still the same fault, last month changed it for a non branded one from LSC (Vaux-World) and changed the antifreeze for the second time (GM Vauxhall's Red Dexcool set at 50% mix rate), set the interior heater to max heat and the interior fan on max, expansion tank cap off and let the engine tickover both times to purge any trapped air out of the cooling system. When up to near 90 degrees and the 'stat open, refitted the expansion tank cap and took the car out for a 5 mile drive only to get the same problem. No sign of bubbling in the expansion tank due to Head gasket failure. No coolant leakage as tank level is constant. Temperature stated checked on temp gauge and OPCOM. 3 Thermostats in 5 months is a bit much to say the 'stats are all faulty, 2 genuine VX ones and a LSC cheepie. Expansion tank cap changed with another one off one of my other cars, same problem. Radiator fan not kicking in early so to over cool the engine. Last year when changing the stat for the 1st time I did a cooling system flush both directions. So guys, any clues as to why the car takes so long to get up to operating temp on standstill only to drop dramatically when in motion ? Thanks.