The timing belt in your Mitsubishi Montero's V6 engine is one of those invisible components that quietly does its job—until it doesn't. Unlike timing chains, belts have definite service intervals and must be replaced preventively. Neglecting timing belt maintenance can lead to catastrophic engine failure, making this one service you absolutely cannot skip.
Understanding Timing Belt Importance
The timing belt synchronizes the rotation of the crankshaft and camshafts, ensuring the valves open and close at precisely the right moments during the engine cycle. If the belt breaks or slips, this synchronization is lost. In interference engines—where valve and piston paths overlap—a broken belt causes pistons to collide with open valves, destroying the engine.
Timing Belt Service Interval
Mitsubishi typically recommends timing belt replacement at:
- Mileage: 60,000-100,000 miles (varies by model year)
- Time: 5-7 years, whichever comes first
Check your owner's manual for the specific interval for your vehicle. Age is as important as mileage—rubber degrades over time even with low miles.
Signs the Timing Belt Needs Attention
- Approaching or past recommended service interval
- Ticking noise from front of engine
- Engine misfires (timing slip)
- Oil leak near timing cover
- Visual cracking or wear if inspected
- Engine won't start (belt may have broken)
What's Included in Timing Belt Service
A complete timing belt service typically includes:
Timing Belt
The main component—replaced with a new belt of correct specification.
Tensioner and Idler Pulleys
These components keep the belt at proper tension. Replacing them with the belt prevents future problems.
Water Pump
Located behind the timing belt, the water pump is typically replaced at the same time. The labor cost to access it is already covered, and water pump failure after belt service would require paying that labor again.
Camshaft and Crankshaft Seals
Front seals are accessible during timing belt service and should be replaced if showing wear to prevent oil leaks.
Serpentine/Accessory Belts
Often removed to access the timing cover, these may be replaced if aged.
The Service Process
- Remove components blocking access (belts, covers, etc.)
- Mark and align timing marks on crankshaft and camshafts
- Release tensioner and remove old belt
- Replace water pump and seals (if included)
- Install new tensioner and idler pulleys
- Install new timing belt, ensuring proper alignment
- Set tensioner to specification
- Rotate engine by hand to verify correct timing
- Reassemble and test
Choosing a Shop
Timing belt service requires precision. Choose a shop experienced with your vehicle:
- Dealers have factory training and procedures
- Specialized import shops often have extensive experience
- Ask about experience with Mitsubishi V6 engines specifically
- Ensure they use quality parts (OEM or equivalent)
Service Costs
- Timing belt kit (belt, tensioner, pulleys): $150-$400
- Water pump: $80-$200
- Labor: $400-$900 (3-6 hours depending on engine)
- Total timing belt service: $600-$1,200
- Total with water pump: $800-$1,500
Consequences of Neglect
The Montero's V6 is an interference engine. If the timing belt breaks:
- Pistons strike open valves
- Valves bend or break
- Piston and cylinder damage possible
- Repair cost: $3,000-$6,000+ for head work
- Complete engine replacement may be needed
The $800-$1,500 for proper timing belt service is excellent insurance against $5,000+ in engine damage.