My father-in-law has a 2015 Holden Colorado that needs to have the engine oil topped every 1000 km. It’s usually halfway on the dipstick at that time. Holden has put in a thicker oil and that has made no difference, and now they are saying they want to do a test where they make sure it’s all sealed up correctly, even though they tell me that the usage falls within their specifications. But they cannot show me where it says there is that much oil usage. Can I get some advice please?
Halfway on the dipstick suggests that it doesn’t need topping up, try waiting until it gets to the lower mark on the dipstick and see how far that takes you. Holden, or any other carmaker, won't tell you how much oil consumption is ok with their engines, but all engines use some oil. There are two basic reasons an engine might use oil, leaks, or burning. Leaks can usually be seen and easily fixed, burning isn’t so obvious and is more costly to fix. If it is burning oil you should see some evidence in the form of blue smoke from the exhaust. Go along with Holden’s recommendation and do the test.