hie i have 10 years with my lexus is220d sport i previously owned an is 220d sel with so many issues, head gasket bubles in my reservoir tank and overheating , when at low temperatures revs go high to 1200revs , now no issues issues with this sport whatsoever except the cracking noise , everything is super up to now. The car doesnt hv high idling at low temperatures, in fact it idles at 800revs when cold unless you turn on heater then the rev goes up to 1200 , this is done to help engine warm up faster to give you cabin warmth faster. So when your car starts with high revs of 1200 with when cold with your heater off it means there is a problem somewhere with your circuits. This one doesnt hv any head gasket issues and because the car doesnt overheat, overheating in the lexus is220d is caused by a stuck closed thermostart, so regular changing of the thermostart is needed because this diesel operates at high temperatures then the wax in the thermostart is broken down quickly , well though the thermostart is rated at 82degrees, that means it starts to open when temperatures reaches those ranges and circulate thru the engine but then when you are in town that is where the problem is when moving slow , there is no ambient air to cool the radiator so you need to rely on the fans of which the electric fans only kick in when temperature reaches 97 degrees and cools back to 91 or 90 degrees, this means your thermostart is wide open at operating temperature of the engine and gives in quicker. I have done this regular service of the thermostart and the is220d sport runs super fine. Smooth ride , i can maintain 200km/hr for the whole hour without fear of damaging the engine through overheating,No issues whatsoever .i wish lexus never discontinued this diesel or if they can bring another diesel version in future. Throughout the years of owning this car its very reliable, fuel economy is good. Will be buying my new is200t F sport soon but have no intentions of selling my 220d sport.