BMW N20/N26 Timing Chain Replacement
BMW makes legendary engines, known for performance, durability, and elegant design. As engine design has evolved to match demands in performance and efficiency, more complexity exists in modern engines.
The turbocharged 4-cylinder N20 and N26 engines are an example. BMW uses it in a wide variety of modern cars, including the 2-, 3-, 4-, 5-Series and the X1, X3, and X4 SAVs. While these engines are powerful, reliable, and fuel efficient, the timing chains (both the main camshaft to crankshaft, and the oil pump one), need to be checked regularly. Most specialists recommend checking them at every oil change interval (5,000 miles) after 50,000 miles.
1. The issue
The plastic guides that keep the timing chain in place tend to brake over time. As the plastic becomes brittle and cracks under the constant movement of the chain, the guides can no longer keep the metallic chain in place, causing it to stretch and eventually fail. Here is a diagram of the timing system in an N20 engine:
Why do the chains fail? The leading theory is infrequent maintenance. The recommended 10K mile oil service interval causes damage to many engine subsystems - the timing chain among them.
Some symptoms of a bad timing chain are:
a. A whining noise is heard in the engine bay, similar to a supercharger
b. A rattling noise in the engine bay
c. Slow cranking times
d. A check engine line with 'Camshaft to Crankshaft' correlation codes
Also, a qualified specialist like CarHavn with access to a factory diagnostic tool can run a test plan that identifies a stretched chain. A visual check under the valve cover is the definitive diagnostic.
Here is what a broken guide looks like:
The chain and all related components need to be replaced, including:
- Main chain
- Oil chain, and related components
- Guides, tensioners, seals, sprockets
A timing chain is a very precise system – equivalent to the delicate mechanism in a Swiss watch. It requires a very skilled mechanic, specialist mechanical tools, the right laptop for programming, and the right updated parts for a correct repair.
Trust CarHavn for this major job. We have all the elements above, plus we will use the labor hours intelligently, replacing also other components like spark plugs, the valve cover gasket, and camshaft seals for the cost of the parts only. We offer a 24-month, 24,000 mile warranty on this job.
The only thing we don’t have is the crazy dealer pricing. We have seen quotes from the local franchise dealers that makes us dizzy! We have also had cars towed to us after a ‘BMW guy’ attempted and failed at doing this delicate job.
Call a Service Advisor today to understand more, get a quote, and make an appointment.