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A connecting rod links the piston to the crankshaft and takes the full force of every combustion stroke. Rods bend when water is drawn into the engine, and they get damaged when a bearing spins. Route 66 Auto Repair in Upland inspects and measures rods after a hydrolock, a loud knock or a sudden stall, and tells you plainly whether repair makes sense. ASE-certified technicians document the damage with photos, and your written estimate shows every step before work is approved.
When a connecting rod may be damaged
- The engine stalled after driving through deep water
- A loud, sharp knock that appeared suddenly
- Low compression on one cylinder after a hydrolock
- The engine will not turn over by hand after a stall
- A hole in the block or oil pan, which means the rod has already failed
What is hydrolock?
Water does not compress. If an engine pulls water through the air intake, often from a flooded underpass during a rare Upland storm, a piston hits that water and the rod can bend. The engine may stall immediately or keep running with a knock and low compression. Do not keep cranking a stalled engine that took in water. Call for a tow-in and we will remove the plugs and check before anything turns.
How do we inspect rods?
We start with a compression test and a borescope look into each cylinder. If the bottom end is opened, rods are checked for bend and twist, the big end is checked for size and roundness, and rod bolts are inspected. A rod with a spun bearing often has a damaged bore, and the crank journal under it is usually damaged too. See rod bearing repair for the bearing side.
Our connecting rod repair process
Step 1: Safe first check
Plugs out, engine turned by hand, water or debris removed.
Step 2: Test and scope
Compression and borescope results show which cylinders are affected.
Step 3: Open and measure
Rods and journals are measured and photographed.
Step 4: Present options
Rod replacement, a full rebuild or a replacement engine are compared in writing.
What's included in connecting rod repair
Included on the work order
- 01Hand rotation check before any cranking
- 02Compression test and borescope inspection
- 03Rod bend, twist and bore measurement
- 04Photos of damaged parts
- 05New rod, bearings and rod bolts as quoted
- 06Oil and filter change, oil prime and road test
Need-now or need-later?
Need now: call
- Any engine that took in water or knocks loudly: stop driving it
- A rod bearing knock, which can break the rod
Need later: book
- A single low-compression cylinder with no knock, tested further before deciding
- Intake and air filter replacement after a water event, done with the main repair
How pricing and timing work
One bent rod on an otherwise healthy engine can sometimes be replaced. If the block, crank or cylinder wall is damaged, an engine rebuild or replacement engine is often the sensible path. Your written estimate shows every step, and the diagnostic fee is stated at the counter and applies to approved related repair. AAA members save 10% on parts and labor, up to $75, with the card at time of service. Some insurance policies cover flood damage, so ask your carrier.
Aftercare
After rod work, follow the break-in guidance on your invoice and the early oil change. If the vehicle was flooded, have the electrical system checked too; our engine diagnostics page explains that testing.
Frequently asked questions
Can a bent connecting rod be straightened?
We do not recommend straightening a bent rod for a road engine. Replacement is the reliable fix.
My car stalled in water. Should I try to restart it?
No. Cranking can bend a rod or crack the block. Have it towed in, and we will remove the spark plugs and clear the cylinders before anything turns.
Does a rod failure always mean a new engine?
Not always. It depends on what else was damaged. We inspect and measure, then compare repair and replacement costs in writing.