1999 Buick Regal Oil in the coolant overflow container.

1999 BUICK REGAL
12,000 MILES • 6 CYL • FWD • AUTOMATIC
Avatar
CAROLRIENTS
  • MEMBER
  • 2 POSTS
I have oil the coolant overflow container and was wondering what this could be caused by.
Oct 25, 2010 at 11:31 AM
Advertisement
Avatar
KHLOW2008
  • ASE Certified Mechanic
  • 41,814 POSTS
  • ASE Certified Mechanic
Hi CarolRients,

Thank you for the donation.

Possible causes are :

1. Bad cylinder head or gasket. Check the radiator for presence of oil in coolant. Check engine oil for presence of coolant, it would be milky in color.

2. Bad transmission fluid cooler. This would result in oil in radiator as well. Check transmisison fluids for presence of coolant, would be milky pink in color.

3. Someone mistakenly topped up with oil instead of coolant.
Oct 25, 2010 at 11:41 AM
Avatar
RASMATAZ
  • ASE Certified Mechanic
  • 75,992 POSTS
  • ASE Certified Mechanic
Hi CarolRients, Welcome to 2carpros and TY for the donation

If its oil instead of transmission fluid-could be a blown headgasket, cracked head or block and intake leak. Is the temperature gauge acting abnormal? Check the oil lf its milky colored
Oct 25, 2010 at 11:44 AM
Join 2CarPros for free, one of the most advanced car repair communities on the internet. From first-time drivers to seasoned mechanics, everyone is welcome to reply, share details, and get better answers. You can add a temporary image or video first; uploads are limited to 20 MB.
Ask a Free Question
Repair Safety Notice: This information is for general instructional purposes only. Vehicle repair can be dangerous. Verify all information, follow manufacturer service procedures, use proper tools and safety equipment, and consult a qualified repair shop when needed.