I was wondering if anyone could give me some insight on the engine rattle on cold start up which seems to be common on the V8 4.2's. I just bought the car the other day and just noticed it. Car runs strong and the noise only lasts a second or two, but it already is driving me nuts. The place I bought it from told me that they did an oil change and didn't use synthetic oil. Im getting an oil change done in a couple of days to put some synthetic in, but is it true that certain types/ brands of oil can make this noise go away? Any help would be appreciated. Thanks!

 

It's your valves and/or cam chain tensioners. At cold, there's no oil pressure, so they rattle a couple seconds until pressure builds and pumps them up. If it goes away quickly, you're fine. If the rattle remains (a diesel-like clatter), you're going to hate your life - it means the chain tensioners are failing, which I priced out awhile back at $480 per side and which requires engine removal to replace.