Hello My friend drives an Opel Omega 2,2l 16V ECOTEC engine built in 2002 with 99 000km of mileage. From time to time, the hydropumps start to clack. Sometimes when it is cold and sometimes when it is warm. Always at different times. On the engine is 10W40. Wouldn’t it be better to drive the 5W40 or 5W30 as it is in the inspection booklet? Or are the hydros defective?bez one of them? I’ve seen that one costs 45€ + VAT. And how do you build the Ecotec engine? From above,or? Mf G Christian