One problem related to manifold/header/muffler/tail pipe has been reported for the 2007 Honda Civic. The most recently reported issues are listed below. Please also check out the statistics and reliability analysis of the 2007 Honda Civic based on all problems reported for the 2007 Civic.
2007 Honda Civic ex sedan: upon a trip (60 miles) home from the cleveland airport 1-26-10, I smelled coolant burning and a sudden cloud of steam from under the hood. Upon further investigation of this incident, the determined cause was the engine block had cracked allowing coolant to be sprayed onto the manifold causing the burning smell and clouds of steam. While Honda cannot provide a reasoning behind this failure, it appears or would seem to be a casting issue for the 2006-07 models. The car is out of warranty by 35k miles at the time of failure and Honda declined all efforts to assist with this problem. I am hearing and seeing numerous issues exactly identical to mine well within the warranty period for others and Honda is claiming there is "no" problem with these engines. The car has been dealer maintained and has all highway miles due to my job. Not sure how many complaints it takes to issue a recall but there is definitely a problem with the 2007 Civic engine castings. This overheating could ultimately lead to a fire or serious injury should a driver not understand the indicant at hand. I do know there is a TSB regarding this problem #08-044.