Upper Engine Decarbonization
There are a number of competing techniques you can use to try to clean upper-engine deposits that might be causing excessive oil consumption. Here are my two favorites:
1. A thorough injector cleaning, using a MotorVac or similar apparatus, coupled with cleaning the throttle body and induction system. (I like BG spray induction and throttle body cleaner Part No. 406 for this.) At the end, add a can of “5-minute motor flush” to the oil, run for the recommended time interval, then change the oil to remove the crud you’ve just washed into it. Clear any codes you may have set and reset adaptive fuel and throttle trims, if applicable. Take a test drive, and monitor trims.
2. An overnight soak with GM’s “X-66” or a similar product. Prepare the vehicle by first warming it to normal operating temperature, then park it on level ground outside. The area underneath the engine compartment may get pretty contaminated, so an absorbent mat, oil-dry or even used cardboard is recommended to help catch and control any runoff or contamination. I like to spray or drizzle a small amount of the cleaner through the throttle body, then dump in a bunch to flood the engine. (Be careful: Liquids are incompressible, so you can bend a rod if you get too carried away!)
Now remove the spark plugs and disable the fuel and ignition systems. Carefully pour some of the cleaner into each plug hole using a narrow funnel. Use the crankshaft pulley bolt to slowly turn the motor through two complete revolutions, pausing along the way to add more cleaner into each plug hole as needed. Cover the engine to prevent anything from falling into the holes, then close the hood and wait until the next day.
Overnight, the solvent will soften up even hardened carbon deposits. The next day, remove the cover, then slowly turn the engine through at least two complete revolutions by hand to allow the remaining liquid cleaner to be pushed out through the plug holes onto the mat, oil-dry or cardboard.
Now you can use a remote starter button, or crank the engine with the key for 15 to 30 seconds. Reinstall or replace the plugs, reenable the fuel and ignition systems, then start the engine. (You may have to hold the accelerator pedal down somewhat if you still have some solvent flooding the engine.) A large cloud of smoke out of the tailpipe is normal, and should clear up after a few minutes of running.
Allow the engine to warm up to normal operating temperature. Clean up your oil-dry or cardboard, then add a can of “5-minute motor flush” to the oil, run for the recommended time interval, then change the oil to remove the crud you’ve just washed into it. Clear any codes you may have set, reset adaptive fuel and throttle trims, if applicable, and test drive. If you wound up with some solvent on the underside of the hood, be sure to wipe it down before it strips off the paint. (Don’t ask me how I know!) Neutralize and remove any remaining solvent with a soap & water solution.
If your inspection reveals a lot of oil sludge as well, you might try substituting one quart of ATF for some of the crankcase oil. Its higher detergent levels may help keep things a bit cleaner, but be sure to explain to your customer the importance of changing it out well within 3000 miles, as the detergent loses its effectiveness. Most customers will comply with this once they understand the rationale. You can continue this substitution at each change interval indefinitely.
BG Products also offers the Squid Combustion Chamber Decarbonizing System (Part Nos. 9404 and 9408) to rotate the engine incrementally—essentially by “bumping” the starter motor—automatically during the clean-soak phase. Its apparatus includes an octopus configuration that allows the solvent to be pushed back into a central reservoir as the pistons rise, then return to the combustion chamber as they fall. Because of its ability to rotate the engine on demand, this system can drastically cut the time needed for a thorough cleaning, but the ultimate time constraints stem from the basic chemistry involved, though, so don’t try to hurry things too much!
And This.
Motor Magazine 2014
There are a number of competing techniques you can use to try to clean upper-engine deposits that might be causing excessive oil consumption. Here are my two favorites:
1. A thorough injector cleaning, using a MotorVac or similar apparatus, coupled with cleaning the throttle body and induction system. (I like BG spray induction and throttle body cleaner Part No. 406 for this.) At the end, add a can of “5-minute motor flush” to the oil, run for the recommended time interval, then change the oil to remove the crud you’ve just washed into it. Clear any codes you may have set and reset adaptive fuel and throttle trims, if applicable. Take a test drive, and monitor trims.
2. An overnight soak with GM’s “X-66” or a similar product. Prepare the vehicle by first warming it to normal operating temperature, then park it on level ground outside. The area underneath the engine compartment may get pretty contaminated, so an absorbent mat, oil-dry or even used cardboard is recommended to help catch and control any runoff or contamination. I like to spray or drizzle a small amount of the cleaner through the throttle body, then dump in a bunch to flood the engine. (Be careful: Liquids are incompressible, so you can bend a rod if you get too carried away!)
Now remove the spark plugs and disable the fuel and ignition systems. Carefully pour some of the cleaner into each plug hole using a narrow funnel. Use the crankshaft pulley bolt to slowly turn the motor through two complete revolutions, pausing along the way to add more cleaner into each plug hole as needed. Cover the engine to prevent anything from falling into the holes, then close the hood and wait until the next day.
Overnight, the solvent will soften up even hardened carbon deposits. The next day, remove the cover, then slowly turn the engine through at least two complete revolutions by hand to allow the remaining liquid cleaner to be pushed out through the plug holes onto the mat, oil-dry or cardboard.
Now you can use a remote starter button, or crank the engine with the key for 15 to 30 seconds. Reinstall or replace the plugs, reenable the fuel and ignition systems, then start the engine. (You may have to hold the accelerator pedal down somewhat if you still have some solvent flooding the engine.) A large cloud of smoke out of the tailpipe is normal, and should clear up after a few minutes of running.
Allow the engine to warm up to normal operating temperature. Clean up your oil-dry or cardboard, then add a can of “5-minute motor flush” to the oil, run for the recommended time interval, then change the oil to remove the crud you’ve just washed into it. Clear any codes you may have set, reset adaptive fuel and throttle trims, if applicable, and test drive. If you wound up with some solvent on the underside of the hood, be sure to wipe it down before it strips off the paint. (Don’t ask me how I know!) Neutralize and remove any remaining solvent with a soap & water solution.
If your inspection reveals a lot of oil sludge as well, you might try substituting one quart of ATF for some of the crankcase oil. Its higher detergent levels may help keep things a bit cleaner, but be sure to explain to your customer the importance of changing it out well within 3000 miles, as the detergent loses its effectiveness. Most customers will comply with this once they understand the rationale. You can continue this substitution at each change interval indefinitely.
BG Products also offers the Squid Combustion Chamber Decarbonizing System (Part Nos. 9404 and 9408) to rotate the engine incrementally—essentially by “bumping” the starter motor—automatically during the clean-soak phase. Its apparatus includes an octopus configuration that allows the solvent to be pushed back into a central reservoir as the pistons rise, then return to the combustion chamber as they fall. Because of its ability to rotate the engine on demand, this system can drastically cut the time needed for a thorough cleaning, but the ultimate time constraints stem from the basic chemistry involved, though, so don’t try to hurry things too much!
And This.
Motor Magazine 2014
