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Anybody ever done a "top engine cleaning" or know how to do it?

4048 Views 4 Replies 3 Participants Last post by  paulo57509
Looking to do a top engine cleaning which is designed to clean carbon deposits from engine and other areas of the engine. The primarily method is using a liquid (not spray) top engine cleaner such as the GM Top Engine Cleaner. Does anyone know exactly how the pass the cleaner into the engine? I understand it's done through a vacuum line but I have no idea which one. Thanks.
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Question: Why do you want to do this? Unless there is a specific problem you're trying to fix, it isn't worth the trouble.


Make up a hose and funnel to introduce the cleaner into the engine. I fit the hose/funnel to the breather cover where the PCV hose is connected (not the cover in the valve cover). Grab a small pair of Vise-Grips too.

Get yourself a feeler gauge and peel off enough leaves so that when you stick the leaves between the dashpot and the lever on the throttle body, it will hold the engine at an elevated RPM.

Now you're ready.

Drive out to a secluded area. When you start to pour this stuff in, your engine will smoke like it's on fire. I doubt your neighbors will appreciate the smoke...especially if their windows are opened.:D

Turn off the engine and remove the PCV hose and fit the hose/funnel to the engine. Pinch off the hose with the Vise-Grips.

Start the car wedge in the feeler gauge between the dashpot and the lever to get and keep the RPM's up. Partially fill the funnel. Remove the Vise-Grips and continue to pour the cleaner into the funnel per the instructions on the can.

I couldn't get the engine to stall like the instructions read because the hose can only introduce the cleaner at a fixed rate; not enougn to choke it off. It might work if you pull the feeler gauge off.

Let the engine sit for 15 minutes (IIRC). Take off the hose/funnel and reconnect the PCV hose, returning this to where they were.

Start the should smoke a bit more. After the smoke clears, you're done.

Now, an alternate way of doing it the way they do it at GM dealerships. They did this to my IROC and my part throttle ping went away. Some do the above and follow with the procedure below:

Start with a cold engine and remove the spark plugs.

Fill a squirt-type oil can with the cleaner and squirt the stuff into the spark plug holes.

Tap the starter to crank the engine a bit at a time to distrubute the cleaner. A few more squirts wouldn't hurt.

Re-install the plugs and let the car sit overnight.

Alternate method: Using the hose/funnel above. just pour it into a cold engine. Not the whole can; about 1/4 the can is fine. The idea is to get the carbon wet, not fill the cylinders with cleaner (can you say, bent rods?) Disconnect the coil wire and tap the starter to distribute the cleaner. Pour in another 1/4 can.

Next morning, start the car. You might have to hold the pedal to the floor (clear-flood mode) to get it to start. The engine will run rough but use the gas pedal to keep it running. Again, it will smoke.

After the smoke clears, change the oil and filter. This is MANDATORY.

Good luck.
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Thanks. What about using the cruise control connection at the trottle body or and the red woven hose from the charcoal canister just above where the intake tube connects to the throttle body (connects above idle screw).
upper engine clean

Look for a mechanic who does Motorvac. Takes about one hour and cleans the parts of the engine where carbon has built up.
Available all over Canada.
Rick90Legend said:
Thanks. What about using the cruise control connection at the trottle body or and the red woven hose from the charcoal canister just above where the intake tube connects to the throttle body (connects above idle screw).
Rick, you need to use a hose witha large enough cross section to introduce the cleaner at a large enough volume.

As an alternate to the PCV hose, you can use the power brake hose connection.

It just dawned on me that you might be able to "take apart" the air intake duct at the throttle body and turn the section of duct connected to the throttle body upwards and pour the stuff right down it's throat.

It might be worth your time to contact the local Acura/Honda dealer to see if they offer this kind of service.
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