Clattery when cold
Join Date: Feb 2012
Location: United Kingdom
County: Greater London
I don't want to alarm you but please do make sure it isn't hydraulic (brake/clutch) fluid, which looks oily and tastes sweet (but is very poisonous so don't taste it). It is also highly flammable and can ignite on a hot exhaust manifold, unlike oil or petrol, and is the major cause of engine fires.
Coolant nowadays (since 2002 IIRC) should have Bitrex in it to deter kids and pets from drinking it, and it no longer tastes sweet.
I don't know the V6 engine bay but the brake fluid reservoir is nearby and there will be pipes feeding fluid to the brake and clutch master cylinders inside the passenger compartment, so it's worth checking. Also check the level in the reservoir to make sure it isn't dropping. If it is brake fluid don't run the engine until fixed.