A refrigerant leak may develop from the AC evaporator causing the AC to blow warm air. Verifying failure of this component is difficult. A good shop will use leak detection dye to verify a failing evaporator.
Honda Civic Si Problem Reports
Most Reported Honda Civic Si Problem Reports
Certain manual transmissions can cause a clicking noise when turning right due to a reverse gear contacting other gears in the transmission. The transmission needs to be disassembled and new updated gears need to be installed to stop the noise.
An oil leak at the spark plug area (spark plug tubes) can be caused by a failing valve cover sealing rubber and/or camshaft holder o-ring. The sealing rubber and o-ring will need to be replaced to address this issue.
A faulty brake master cylinder reservoir filter can cause the brake system indicator to illuminate after a cold start and then go off. Replacement of the reservoir filter will commonly fix this problem.
Some Honda Civics have seat belt issues that may be covered under Honda's Lifetime Seat Belt Limited Warranty. Please contact your local Honda dealer to see if your seat belt problem is covered.
On certain models in colder climates the Check Engine light can set due to moisture in the Manifold Absolute Pressure (MAP) sensor freezing. The MAP sensor needs to be replaced and on some models the intake manifold needs replacing also.
CVT models (HX and GX) have a shudder, judder, and noise due to a worn start clutch in the transmission. Replacing the start clutch is needed to address this issue.
A worn (front) bushing on the rear lower control arm can cause a noise when going over bumps. Replacing the worn bushing should stop the noise.