Chrysler Replacing Defective V-6 Cylinder Heads

Chrysler Group LLC has been installing "more robust" cylinder heads on thousands of customer vehicles powered by the company's 3.6-liter Pentastar V-6 engine, Automotive News reports.

The engine currently is used in Chrysler's Grand Cherokee and Wrangler SUVs and Chrysler 300 and Dodge Charger sedans.

Chrysler says the problem, which it does not describe in detail, is not a design defect and occurs only in in combination with an unspecified fuel mix and undisclosed driving conditions.

AN says the problem causes the check-engine light to illuminate, may produce a ticking sound and could cause power loss or stalling. Chrysler insists the issue does not totally disable the engine.

The problem affects about 7,500 of the 1.5 million Pentastar engines Chrysler built over the past two years, according to Doug Betts, senior vice president for quality.

The company says its dealers have been filing more than 500 requests per week to replace the heads under warranty. AN isn't clear whether dealers are replacing both heads or only one on each engine.