Starting problems

Car won't start due to a suspected timing issue

If the timing belt or chain has slipped or broken, the engine's valves and pistons fall out of sync, which can cause a crank-but-no-start and, on some engines, serious internal damage.

Difficulty
Professional only
Time
Varies (major repair)
Pro cost
$500–$2500

Symptoms

  • Engine cranks, sometimes very easily/fast, but never catches
  • May have heard a rattling or slapping noise before it quit
  • Check engine light may have been on before the no-start
  • No unusual smell of fuel or smoke necessarily present

Likely causes

  • CommonBroken or badly slipped timing beltOn interference engines this can also bend valves, turning a no-start into a bigger repair.
  • PossibleStretched or jumped timing chainChains are more durable than belts but can stretch and skip over many years.
  • PossibleTiming belt/chain tensioner failureA failed tensioner can cause sudden slack and timing loss.
  • Less commonBroken timing belt/chain cover component interfering with rotationRare but possible on some engine designs.
  • PossibleUnrelated fuel/ignition no-start being mistaken for timingMany crank-no-start issues are fuel or ignition related, not timing.

What to do

  1. Note whether cranking feels unusually easy or 'free' compared to normal, which can be a sign of a broken timing belt.
  2. Check your maintenance records for when the timing belt was last replaced, since most have a manufacturer-specified interval (often 60,000–100,000 miles).
  3. Avoid repeated cranking attempts if you suspect a timing belt failure, since running an interference engine with bent valves can cause further damage.
  4. Have a mechanic check compression on each cylinder, since low or no compression on multiple cylinders points strongly to a timing failure.
  5. If the timing belt is confirmed broken, do not attempt to run the engine again until it's repaired.
  6. Ask whether your specific engine is an 'interference' design, since this affects the severity and cost of a timing failure.
  7. Budget for a more significant repair if timing failure is confirmed, since it typically requires belt/chain, tensioner, and sometimes valve or head work.
  8. Consider this a reminder to follow the manufacturer's timing belt replacement interval on any vehicle going forward.

Tools and parts

Timing belt or chain kitSearch: “timing belt kit for [year make model]”

When to call a pro

A suspected timing belt or chain failure should be diagnosed with a compression test by a qualified mechanic before any further cranking is attempted, since continued attempts can cause additional engine damage.

Safety

Generally low risk

Generally low risk for a careful person. Stop if anything looks different from what this guide describes.

Related guides

Operator provides AI-generated troubleshooting information. It can be wrong. For safety-critical, electrical, gas, structural, medical, automotive safety, or other high-risk problems, consult a qualified professional.