SteveROntario

I have a 2004 Chevy Express 3500 with a 6 litre LQ4 engine and 95,000 miles on the clock. I got this from my parents and my dad has said that it's had an unexplained coolant loss for years. The reservoir level will drop but no drips anywhere. The dealer did a pressure test on the coolant system over night and it was not leaking before I bought it. They also changed the spark plugs at the same time and did not make us aware of anything unusual. While under the van today I noticed some deposits on one of the exhaust pipes just after the passenger side catalytic converter.

What's up with this?

cablesplicer

Not sure if this is your trouble but a friend of mine had a 2001 with the same mistery coolent leak for years . Turned out there was i , i think , a small hose going into the radator [heater hose maybe] that you couldn't see untill you removed everything blocking your view [air cleaner , etc.] that even then was not seen untill he was replcing the radator and turned out had some funky fitting with an o ring i beleave. If you don't get a better idea from another member i could try to get a hold of him to find out for sure. From what i have read it seems to be a common problem with the early 200o's models. I am sure someone here will give you a better answere , just wanted to try to help , and good luck.