Question

in gdi engines, which of the following is the least risky way to remove the carbon on intake valves and runners, especially if the buildup is very heavy?

a. removing the cylinder head, disassembling it, and cleaning it
b. removing the intake manifold and using a crushed walnut shell blaster to blast away the carbon
c. removing the intake manifold and using a chemical cleaner to soften and dissolve the carbon so it can be removed
d. induction cleaning

Explanation:

• Option a: Removing the cylinder head is a major operation with high risk of damage to seals, gaskets, and proper engine alignment.
• Option b: Using a crushed walnut shell blaster is a non - abrasive and effective method. Walnut shells are soft enough not to damage engine components (like valves) while being able to dislodge heavy carbon buildup when the intake manifold is removed (a relatively less invasive removal compared to cylinder head removal).
• Option c: Chemical cleaners may not be strong enough for very heavy carbon buildup and can also potentially damage engine components if not used carefully.
• Option d: Induction cleaning (injecting cleaners through the intake while the engine is running) is less effective for very heavy carbon buildup as it may not penetrate and remove all the carbon thoroughly.

Answer:

B. Removing the intake manifold and using a crushed walnut shell blaster to blast away the carbon