[101Volts]

Dad's 2000 Dodge Caravan 3.0 Litre was rattling and knocking a little bit and using oil a bit excessively though not smoking out the tailpipe. Initially I was using a 5w30 and was topping off with 5w40 Diesel oil and also had a container of STP Oil Treatment in there. So, in attempt to make this rattling and knocking go away we thought to try thickening the oil. I tried finding a 5w40 within certain limits; didn't work. I could've used a Diesel oil and was concerned it would clean the engine too much and increase oil consumption even more, so I didn't use that. I could've used Mobil-1 0w40, it wasn't a High Mileage oil though. So we ended using Pennzoil Conventional High Mileage 10w40 and Lucas Oil Stabilizer; This made the engine go from knocking a little bit, to knocking a lot more. Even after letting the van stay on for over half an hour it still did it.

So, now I'm thinking about taking the oil I drained out of the crankcase and putting that back in. It still has at least 1,500 miles worth of use in it. We changed the filter at least.

Earlier, I changed Mom's van's oil from 5w30 or 10w30 & STP to Castrol Full Synthetic 0w20. The van wasn't rattling before and now I think the fuel economy went up.

EDIT: Somehow this noise stopped being so noisy today. It wasn't so clear in the first hour of the oil change though so take this with a grain of salt, would you?