What to do? Top end knocking bad
Thread Starter
8th Gear
Joined: Apr 2010
Posts: 8
Likes: 0
What to do? Top end knocking bad
Okay so took her to a highly referenced shop in Lakewood WA. They diag the noise a top end. Want 2500 to clean the carbon. They say the only way they'll do though is if I preapprove $7000.00 rebuild in case they get in there and ind that's not the problem.... hmm
Some say try this.
{The oil-sucking problem will cause carbon buildup in the cylinders. The dealership sells GM Top End Cleaner, and Napa sells SeaFoam. The Top End Cleaner is not available in some smog states like California. Run a tube from the bottle into the hole for the PCV system behind the throttle body on the passenger side. Start the car, then start slowly sucking the solution into the engine. Don’t go too fast or the engine could lockup. As soon as the solution is gone, stop the motor for >4 hours, but preferably 12 hours. Be aware that when the engine is restarted, there will be a LOT of smoke!}
Car's now at another shop, mech doesn't want to do the above to assess. he want to send it for rebuild.
N - E ideas..
Some say try this.
{The oil-sucking problem will cause carbon buildup in the cylinders. The dealership sells GM Top End Cleaner, and Napa sells SeaFoam. The Top End Cleaner is not available in some smog states like California. Run a tube from the bottle into the hole for the PCV system behind the throttle body on the passenger side. Start the car, then start slowly sucking the solution into the engine. Don’t go too fast or the engine could lockup. As soon as the solution is gone, stop the motor for >4 hours, but preferably 12 hours. Be aware that when the engine is restarted, there will be a LOT of smoke!}
Car's now at another shop, mech doesn't want to do the above to assess. he want to send it for rebuild.
N - E ideas..
Instructor
Joined: Oct 2009
Posts: 212
Likes: 4
From: Parkersburg WV
Ill throw something out here. I am a used car dealer. One time a lady traded in a 02-03 s10 to me. She bought it new and NEVER changed the oil, not once. With 45k miles on the odometer the oil was like thick clay when i pulled the drain plug it came out in clumps. Put a full bottle of seafoam on oil. Let the truck run an hour. Pulled drain plug and it was almost totally thin. Filled with oil, filled with seafoam again and drained. 4 times total and a total of over 4 hours of idle time, the oil came out normal. Have used the truck as a shop truck for 5 years, and has 170k miles on it now never had an isssue. Seafoam is good stuff! Definately worth a try. What do you have to lose?? Use the whole bottle drive 50-100 miles and drain. Do that 2-3 times and see if it doesn't help. Run a few cans through the brake booster vent line also. Stuff really works. Sometimes you have to do it multiple times in severe cases though. With all the carbon its not going to come out in one shot
Safety Car
Joined: Aug 2011
Posts: 4,447
Likes: 409
From: Portland OR
Well, run away from that highly acclaimed shop.......they are taking advantage of your being a Vette owner.
I'd find just a good repair shop, one with a bore scope who can look in the plug hole and verify this so called carbon caused knock.
Carbon can also be removed by trickling water in the TB with the engine running. Very slowly of course.
Seems to me that if you flood it with seafoam, best to let it sit and turn the carbon to goo. Just seems like an odd way to de-carbon an engine.
got a video of the knock sound?
Ron
I'd find just a good repair shop, one with a bore scope who can look in the plug hole and verify this so called carbon caused knock.
Carbon can also be removed by trickling water in the TB with the engine running. Very slowly of course.
Seems to me that if you flood it with seafoam, best to let it sit and turn the carbon to goo. Just seems like an odd way to de-carbon an engine.
got a video of the knock sound?
Ron
Melting Slicks
Joined: Jan 2009
Posts: 3,181
Likes: 286
From: Puyallup Washington
Corvettes of Auburn is a good place. They know Corvettes and have done good work for me at a reasonable cost on both my 1992 and my 2002. Give Dan a call. Definitely run from where it is now unless you want to get made love to without even getting a kiss.
