1999 Venture "using" coolant

for the past 3 or 4 years, my 1999 Venture has leaked or used Dex coolant. Mechanics are unable to locate the leak. This stuff cost $10/gallon, so replacing 1/2 gallon or so every 1-1/2 months is getting expensive. Any suggestions?

It's either burning off externally (sweet smell when you open your hood), burning off as part of the combustion gases (white smoke), or leaking into your oil (mayo-like goop in your oil cap). You can have your oil examined by an a company like Blackstone Labs to rule out the oil route for $20 or so. You can also get a UV dye to help track down external leaks.

A mechanic should be able to find a coolant leak.

Have you considered leaking from the water pump?

It's either burning off externally (sweet smell when you open your hood), burning off as part of the combustion gases (white smoke), or leaking into your oil (mayo-like goop in your oil cap). You can have your oil examined by an a company like Blackstone Labs to rule out the oil route for $20 or so. You can also get a UV dye to help track down external leaks.

Thank you for the suggestions. No mayo on the oil filler - oil stays clear throughout life of change. I've not noticed a sweet anti-freeze smell in the exhaust either or white smoke, but haven't smelled under the hood.

The water pump is a good candidate. How would one determine if the WP has a sloooow leak (takes over 1-month to go down significantly)?

Thanks
stardot

Usually it will leak at the weep hole. When mine went I had to actually watch it idling and I saw little droplets fly off the pulley. Our leak too was quite slow. When coolant comes out of the weep hole it is an early warning that the water pump bearing is worn and failure will soon follow.