My 05 TL with Automatic Transmission has about 95,000 miles on it. I came back from a short trip away (1 week) and noticed the engine ran slightly rougher than normal. I looked under the hood and noticed the antifreeze was significantly lower than the minimum. I also noticed some white smoke coming from the dual exhaust. It isn't heavy at all, it's barely noticeable but it is white. My question is, could I have blown a head gasket? No check engine light or service code has popped up...I thought the TL has sensors for that sort of thing and would come up with a service engine light or something. Am I just being paranoid?

 

What do you mean by "significantly below minimum"? There is not much room in the reservoir below the "min" marking. Significantly below "min" would mean it was empty to me. What about the radiator itself? Did you remove the radiator cap and check it?

It's really hard to tell from here, but those are indeed signs of a blown head gasket (rough running, loss of fluid, white smoke). However, they could be coincidental as well. When was the last time you checked the fluid (both in time and miles driven)? Check your oil, does it look milky (check dipstick and remove oil add cap and check)? Has the temp gauge read higher than normal?

If your oil is milky, you've got a BHG. If not, add fluid back and monitor it for the new few days. I'd go easy on the engine until you can make a determination.

 

Sounds like a head gasket unfortunately. Keep us updated and check your oil as suggested.