Can I have some advice please - I've got an Isuzu Bighorn (at least thats what its called here in New Zealand), 3-litre double o/head cam turbo diesel, uses oil pressure to activate the injector pump. When the motor is cold, regardless of the air temp (and the temp here can drop to -7C, rises to 30C)it will take 10 to 15 revs on the starter before it fires - when the motor is warm/hot/been in use it will fire after 3 or 4 revs. The manufacturers recommend 5W-30 - my question is, will)OW-30 improve how quickly it will build pressure and activate the injectors when the motor is cold?