Discussion Starter · #1 ·
As promised, here is the official statement from GM. Tom Read (GM Powertrain Communications) has run this by both GM Service Engineering-the guys who engineer fixes for issues (Detroit), and GM Product Engineering-the guys who designed the motor (Germany for approval. This is about as official as it gets.
In a follow-up to your question regarding the correct spark plug gap for the Cruze 1.4L turbo engine I worked with our product and service engineering teams to get these answers back to you. Feel free to pass this information on to others.
The 2012 North American Cruze Service Manual spark plug gap information was incorrectly listed as 0.85 - 0.95 mm. A change is being implemented to correct that information to 0.6 - 0.7 mm. This information is in the process of being updated in dealers online service information. A service bulletin will not be issued. The spark plug gap for the Cruze 1.8L engine is the same: 0.6 - 0.7 mm.
The 2012 and 2013 North American Cruze Owner’s Manual spark plug gap will remain unchanged at 0.7 mm as they are already printed. The gap is the same for all North American model Chevrolet Cruze models with the 1.4L and 1.8L engines regardless of model year.
We are investigating changing future Owner’s Manual information to state the range, vs. just 0.7 mm which is the high limit, to be consistent with the Service Manual.
The spark plug gap is determined by many engineering factors including durability. While there may be seemingly short term advantages to changing the manufacturer’s specified spark plug gap there are potential negative effects. We appreciate customer’s desire to improve performance but please know your engine has been engineered to perform optimally with the original manufacturer’s specifications and we do not recommend altering these specifications.
I hope this resolves your questions. Thanks to you and all of the Cruze owners for bringing the plug gap discrepancy to our attention.
GM Technology Communications, Powertrain