Chevrolet Repair: Coolant Loss, oil drain plug, coolant loss

Question
CJS;

I have a 2001 Chevrolet Silverado V6 with 82000 miles and a strange loss of coolant.  When i bought the truck new, the salesman told me that the first time i used the heater in the winter, the coolant level in the recovery tank would fall a bit, and to just fill it up and it would be okay.  The first winter i had the truck, it did as he said, but the coolant level continues to fall gradually over the course of a month or so until it is low enough to trigger the low coolant light.  Once the light comes on, I fill it up a little past full, and by the next day the level has fallen some, then it falls more over three or four weeks until the coolant light comes on again.  I've checked around the hoses, water pump, and radiator and do not see any sign of a leak or any kind of seepage.  However, about three weeks ago there was a small puddle about the size of my hand underneath near where the oil drain plug was.  It was hard to tell what the fluid was, but it was thick and oily, and had a pinkish/orangish tint to it.  I've checked the oil, and the oil level is fine (no foam to indicate coolant in the oil) but i'm stumped as to how that puddle started way back there near the oil drain plug.  I have an extended warranty that expires this JUly, so I'd like to know if i should have it looked at now, or wait until the problem is more pronounced.  Thanks in advance...

--vrk  

Answer
Hi Ryan,

I think you have enough evidence to take it in.  If you wait, it may not get worse until you are past the warranty deadline.  

Your year makes me think you use the pink antifreeze.  That would explain the color.  You obviously have a leak, and I suspect the intake manifold.  That has been a problem for GM.  A slight leak would cause you to burn the liquid off as the motor runs.  The puddle was caused when too much liquid was present and the motor was turned off.  It spilled onto the ground until the motor parts cooled off, and sealed back up.  

If you have been burning coolant, the O2 sensor may be whacked now.  That could cause fuel economy loss.  Possibly the CAT can have problems now, too.  

Hope this helps.

C J S