A burning smell during acceleration in your 2023 Volvo XC90 can originate from several systems that experience increased stress under load. Identifying when and how the smell appears helps narrow down the source for effective diagnosis.
Potential Causes During Acceleration
Burning smell specifically during acceleration can result from serpentine belt slipping under increased engine load, clutch slip in manual or automated manual transmissions, brake drag from stuck calipers being more noticeable under power, turbo oil seals leaking oil onto hot housings, and engine oil burning from unidentified leaks being vaporized on hot components under load.
Belt-Related Smell
The serpentine belt drives multiple accessories. Under hard acceleration, increased alternator and AC compressor load can cause a worn or loose belt to slip. This creates rubber burning smell and often squealing noise. The smell appears specifically during acceleration demands.
Turbo-Related Smell
Turbocharged XC90 models develop high boost during acceleration, which can stress turbo seals. Oil leaking past turbo seals onto the extremely hot housings creates burning smell concentrated during boost events. Check for blue smoke accompanying acceleration.
Brake Drag Symptoms
A stuck brake caliper causes constant friction that produces heat. While present at all times, the smell becomes more noticeable during acceleration as you're moving faster past the heated brake. One wheel will be notably hotter than others if this is the cause.
Diagnostic Approach
Note smell characteristics and accompanying symptoms. Check if smell correlates with engine RPM (belt, engine) or vehicle speed (brakes). Listen for squealing that might indicate belt slip. Feel wheel temperatures after driving. Check for smoke from engine bay or wheels. Inspect belt condition and tension. Have brakes checked if one wheel is hotter.