Description Heat problem I know there is a lot on this subject, but I don’t get any further… I drive a 612 d, built in 1997, with the five-cylinder OM 602 diesel engine with a cylinder capacity of 2.9 l . When you start the engine and start the engine, the temperature pointer blows out temporarily up to 130 and goes back to the normal range. This then until it is at about 90 degrees. If it is at 90 degrees the pointer swings up to 130 degrees and remains predominantly in the red range. If you drive faster than 60 h/km it goes back into the red area and only if you give full gas, the temperature rises at 90 degrees, you take gas away, the pointer goes back into the red area. So I can drive with 110 full gas and it does not overheat. In the traffic jam – even in summer – the temperature remains at a constant 90 degrees. The small circuit is hot, the heat is heated, the heat is heated. large circuit – the upper thick hose gets hot, the lower hose on the cooler gets very late lukewarm. The cooler doesn’t get really warm. The thermostat was changed on holiday from a workshop (the old one checked and it was fine) and the cooling water completely renewed. An additional temperature sensor was installed on the engine block at the upper rear engine block. This adjusts at approx. 100 degrees. Is it an electrical problem, or the water pump or the viscolü fter? Thank you for your help in advance. LG Klaus