What does burning coolant smell like in a Mazda RX-7 FD?

If you are experiencing a burning coolant smell in your FD RX-7, there are several common causes and critical safety checks to be aware of:

• Common Leak Sources: A coolant smell that enters the cabin often originates from smoke on the passenger side of the engine bay near the exhaust ⁴. This is typically caused by leaks from the rubber turbo coolant feed lines, the heater core lines running above the turbos, or the throttle body coolant hoses leaking and pooling on top of the rear iron ⁴.
• Safety Warning: It is highly recommended not to drive the car until the leak is located and repaired, as coolant (antifreeze) can catch fire if it leaks directly onto a hot turbo ⁴. Additionally, small coolant leaks can quickly turn into major leaks and cause sudden engine overheating ⁴.
• Diagnosis: Performing a cooling system pressure test is the best way to accurately track down the source of the leak ⁴.
• Coolant Condition: If you drain your radiator and the fluid itself smells burnt, check its appearance. If the fluid looks brownish or rusty rather than a clean, normal green color, a full system flush is likely required ².