Questions and Answers
Carbon Up The Valves
Q. Vince, I just bought a 1989 Corolla Wagon in mint shape but it doesn't want to start. Took it to the dealer and after 7 days they said everything was O.K, except they felt it was carboned up bad, this side of a valve job, How may I correct this problem??? it has 121,000 miles on it. Other wise it runs great. Also a second Toyota dealer gave the same answer.
Thank you,
BruceA. If they are referring to the valve stems being carboned up, you have two options. One is the valve job. The second is walnut shell blasting. Now I know you just said; "What the hell is walnut shell blasting?" You did, didn't you?
Well, walnut shell blasting is the same thing as sandblasting except with, yep, you guessed it, walnut shells. The intake and exhaust manifolds are removed to expose the valve stems and crushed walnut shells are propelled by high pressure air to blast the carbon off the valve stems. Now the reason why crushed walnut shells are used is that it will not damage the engine if it isn't completely cleaned out. Sand or glass bead will.
