Buy Now | Log In | ALLDATA Corporate Site | AutoZone.com
Back To Home Page
Log In To Your Subscription
Go To ALLDATA Back Home
Buy A Subscription! Back Home About ALLDATA Information View Sample Vehicles Read Testimonials View Factory Service Bulletins and Recall Titles Contact Us
Dowload Our Navigation Chart
February 2015: New vehicles added including 2014 GM.
• View New Vehicles
October 2014: Release of 2013 along with initial 2014 Vehicles
• View Vehicles
View All News and Updates:
• Go To News
Tech Tips
  Read All Tech Tips

ALLDATA Tech Articles Are Updated Weekly
• View All Tech Articles

  Dodge Durango: Brake Pulsation Problems In Paul's Durango
• Read Dodge Article
 
Fixing A Smelly Audi Audi Tech Tip: A4 begins to Smell caused by a Faulty Hose Composition
• Read Audi Article
Why Do You Need To Change Your Timing Belt? Why Replace Your Timing Belt
• Read Belt Article
Jim Grant Tech Tips Jim Grant Tech Tips
A collection of helpful articles based on reader submissions
Home >> Featured Tech Articles >> Go Back
   
  Jim Grant's Tech TipsJim Grant's Tech Tips
Below is a collection of Jim Grant's Tech Tips sorted by Vehicle Make. These Tech Tips were answers to questions submitted to Jim by ALLDATAdiy.com users over the course of many years.
If you have any questions, please feel free to email us.
 
 

Miscellaneous
Acura
Audi
Buick
Cadillac
Chevy
Chrysler

Dodge/Plymouth
Ford
GMC
Geo
Hyundai
Honda
Isuzu

Jeep
Lexus
Lincoln - Mercury
Mazda
Mercedes
Mitsubishi
Nissan
Oldsmobile
Pontiac
Saturn
Subaru
Toyota
Volkswagen
 
   
  Jim Grant's Tech Tips

'99 GMC K2500, Cold Start Knock

Q: First thing in the AM the engine in my '99 GMC K2500 has a cold start knock (piston slap during deceleration or coming off fast idle) which lasts for approximately one minute depending on the outside air temperature. I first saw an article that was from CLICK and CLACK and in the newspaper. I called the GMC Service 800 number.. They said to have the problem confirmed by a GMC Dealer and they would add 100K miles to my warranty. The question: What is the real cure for this problem and how will it be resolved?.

A: Oh, yes there is a buzz in the trade regarding the piston slap/knock noise problem that GM is having. The other manufacturers (Nissan Ford to name a few) that have been through this problem are just grinning like the Cheshire cat over this issue. What is the real cure/fix? Depends on if it is a piston problem, cylinder problem or both. To answer that requires, removal, disassembly and inspection of the engine. In today's engine the focus is on light weight and reduced friction. On the inside of engines this philosophy is being pushed to the limit and the limit is biting back. The dilemma is that the piston, when cold, has too much room to move inside the cylinder of the engine. With extra room the piston slaps the side of the cylinder wall, which results in a knocking noise, until the piston and cylinder warm-up and reduce the room available for dancing. How big will this problem become for GM? It's hard to say. There are a lot of GM engines with this piston design. GM is stepping up and saying they'll provide an extended (if that's the right wording) warranty on their engines because it's not a problem. The quandary is, it takes time/mileage or a disassembled engine before the real answer is known.

 
     
Have any Questions About ALLDATAdiy.com? Please Email Us
Buy Now | Log In | About | Sample Vehicles | Testimonials | Join Affiliate Program