# Sludgy Anti-Freeze

**URL:** <https://community.cartalk.com/t/sludgy-anti-freeze/7501>\
**Category:** Maintenance/Repairs\
**Created:** [November 20, 2007, 9:16pm UTC](https://community.cartalk.com/t/sludgy-anti-freeze/7501 "2007-11-20T21:16:07Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![unbehaun](https://avatars.discourse-cdn.com/v4/letter/u/e8c25b/32.png) [@unbehaun](https://community.cartalk.com/u/unbehaun)\
**Post date:** [November 20, 2007, 9:16pm UTC](https://community.cartalk.com/t/sludgy-anti-freeze/7501/1 "2007-11-20T21:16:07Z")

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11K miles ago, I put in a near-zero mileage 3.1 into my '95 Cutlass Supreme that had been salvaged and sat for 12 years. Also installed new hoses & radiator but left the old heater core. While changing out the thermostat the other day, my mechanic noticed that my anti-freeze was sludgy. He recommended getting the coolant system flushed and to put new anti-freeze in. He also recommended not using Dex-Cool, opting instead for the green stuff. Why is my anti-freeze sludgy and is this advice sound?