Cleaning your engine of evil carbon

[eldorado1]

The following is straight from a service manual, in regards to the TSB issued for a "cold knock" on the northstar, caused by excessive carbon.

Before considering major engine repairs, the technician should perform the following procedure to clean carbon from the engine combustion chambers.
Note: This procedure must be strictly followed. Hydrostatic lock may result causing severe engine damage if this procedure is not strictly adhered to. (that's important.)

1) Obtain one can of GM TOP engine cleaner (TEC) P/N 1052626.
2) Start the engine and bring the engine coolant temp to 200 degrees on the instrument panel gauge. (220F on a scan tool)
IMPORTANT: Do not raise the engine speed above idle
3) with the engine idling, disconnect the PCV hose from the PCV valve and slowly spray the TEC into the end of the hose.
4) Raise the engine speed to approximately 2000 rpm until you see a cloud of white smoke coming out of the exhaust pipe, then shut off the engine.
5) Let the vehicle sit for at least 20 minutes, preferably overnight. This allows time for the TEC to act on the carbon deposits.
6) Once the soak period has been completed, start the engine and proceed to remove the remainder of the TEC from the engine by increasing the engine speed to 2000rpm until the white smoke has diminished.

For engine-diy-novices, I recommend you follow that advice, and make SURE you get the aerosol can of TEC. It's much less likely to hydrolock the engine, and you can't pour it in too fast like you can with the bottle. After you finish the above, take it on a highway on-ramp, and with the shifter in 2nd, floor it. You can further exercise the rings by letting the car speed drop to 30mph, and flooring it back up to 60....

Oh, you're going to want to change your plugs after you do this. A lot of crap gets moved around, and some of it can collect in the plugs, shorting it out. Also some of the cleaning solution leaks past the rings, so if you leave it overnight (recommended), change the oil. It's not urgent, and it's not even mentioned in the article, but it probably does change the oil chemistry. So why chance it...

[eldorado1]

Please note the above is for 95+ northstars. The fluid should go to the middle nipple on top of the manifold. Don't pour it into the valve cover or something... Just follow the rear PCV hoses.

[Big_Blue]

I use seafoam to clean my carb on my 86 (307)and pretty much use the same steps as well. I just dont go on the highway.

[LT5]

Another Seafoam user here. I use it on all my car's and outboard engines

[mikes93sedandeville]

Jiffy Lubes and many quick lube places have a fuel induction service which is very similar although you must make sure they do it right. BG makes an excellent product and i have found that any throttle bottle intake cleaner or carb cleaner does just as good a job. I used to manage a JL and was very good at preforming the service in a reasonable time and doing an effective job i also studied all the ingredients on several different products and all of em are pretty much the same. Myself im a penny pincher i go to autozone advance etc... buy throttle body intake cleaner 8 spark plugs(not needed if u put old plugs in before you clean) 2 cans of fuel( kind you pour in tank) cleaner and probably a new air filter if its dirty and fuel mileage will jump and all for the price of any cleaner or cleaning a dealer will charge ya!

[eldorado1]

Originally Posted by LT5

Another Seafoam user here.

Seafoam doesn't contain 1/2 the ingredients TEC has.

Seafoam ingredients:

Isopropyl Alcohol (rubbing alcohol), pale oil, and naptha.

GM TEC ingredients:
2-BUTOXYETHANOL, naptha, 4-METHYL-2-PENTANOL, 9-OCTADECENDIC ACID.

This taken from their respective MSDS sheets. Anyone who tells you TEC is the
same as seafoam hasn't smelled TEC... pew! "So bad, it has to work!"

Just to follow up on the instructions given above, you want to pour the entire can in (slowly) the vacuum hose. One that feeds ALL of the cylinders (brake booster or PCV). Then you hop in the car, raise the idle to 2000rpm, and shut it down when you see the white smoke.

[LT5]

Originally Posted by eldorado1

Seafoam doesn't contain 1/2 the ingredients TEC has.

Seafoam ingredients:

Isopropyl Alcohol (rubbing alcohol), pale oil, and naptha.

GM TEC ingredients:
2-BUTOXYETHANOL, naptha, 4-METHYL-2-PENTANOL, 9-OCTADECENDIC ACID.

This taken from their respective MSDS sheets. Anyone who tells you TEC is the
same as seafoam hasn't smelled TEC... pew! "So bad, it has to work!"

Just to follow up on the instructions given above, you want to pour the entire can in (slowly) the vacuum hose. One that feeds ALL of the cylinders (brake booster or PCV). Then you hop in the car, raise the idle to 2000rpm, and shut it down when you see the white smoke.

Point well taken. Thanks !

[N0DIH]

I am assuming that the "TEC" is X66P or X66A, correct?

X66P is pour through, X66A is aerosol. Excellent stuff. My 307 benefited from it in the pinging dept about every 1-2 years.

This stuff is great throttle body cleaner too. Always clean the backside of the blade, that is where it is often pretty nasty.

[ELDORACER]

i have heard that you need to vacuume it out after it soaks is this true

[eldorado1]

No, you do not. I'm sure if you poured it directly in the cylinders you would, but when introduced through the intake with the engine running, you do not. Follow the directions above carefully. Do not use those listed on the label - they are generic instructions that may damage your northstar.

[ELDORACER]

i was trying to clean out my carbon deposits from my engine because i just got my car and i heard that cold engine knock was a problem with the northstar engine. i followed the directions left in a post. i got a arosol can of top engine cleaner and i warmed up the engine to operating temp and then i put it in the pcv valve everthing was going good i then reved the engine to 2000rpms and the white smoke started comming out it was making a funny sound so i let my foot off the pedal and the engine stalled. did i do something wrong. put to much cleaner in. i hope i didnt hydrolock my engine

[N0DIH]

Nope, you didn't read all the directions.

You do as you were doing, don't let up on the gas, maintain 2000 rpm or so, then when it tells you to, allow it to stall. And spray in the rest. So being you stalled, just restart and get it going again. You spray it in at the end to stall it so it is loaded heavy in the cyls to sit and cook (hot engine) it off.

I use X66A (aerosol), X66P (pour), or the garden hose. All 3 work fine. I run the garden hose on low, and dump in to the carb, and rev it to handle it. Runs fine, steam cleans the carbon right out. Just don't stall it with the water. Toss the hose off to the side and rev up to 2500 or so till it is running good, then go for a drive for about 5 miles. It will be fine, and much cleaner. And last time I checked, water is 100% O2 sensor and Catalytic Converter safe! And Genuine 100% Microsoft Free.

Yes, a friend of mine hyrdolocked his engine and bent the rod and shattered the piston (but that was 4 wheeling and he went nose in the water!). Always be exteremely careful inducing water or any other chemical liquid into an engine! If you are not cozy comfy with doing it, then do NOT do it. I am, as I have done it for years on my older cars (301 Turbo Pontiac, 455 and 400 Pontiac, 350 Olds, 307 Olds). Honestly, never did it to a EFI car due to the sideways TB. A spray bottle works well too, and injests less water at each time, and does a fine job. Just spray as fast as you can, it will run fine, and likely not ever come close to stalling.

[mtflight]

Clarification requested: Do you spray the whole bottle in, while the engine is idling AND THEN Rev it to 2000 RPM until the smoke appears?

[ELDOminator]

I'm not sure what you're SUPPOSED to do , but I sprayed it in while it was revved. Then I shut it off, let it sit, and revved the heck out of it after that. While in the cleaning process, thick white smoke completely covered 2 acres of land. It was cooooool!

[mtflight]

Originally Posted by ELDOminator

I'm not sure what you're SUPPOSED to do , but I sprayed it in while it was revved. Then I shut it off, let it sit, and revved the heck out of it after that. While in the cleaning process, thick white smoke completely covered 2 acres of land. It was cooooool!

LOL that does sound cool. Was it really that much smoke? I live in an apartment complex, so... I dunno about all that.

How long did you let it sit? (overnight?)

So you revved it to 2000RPM while you sprayed it in... then you turned it off.
Did someone help you hold it at 2000 while you sprayed??

Did it get rid of some of the carbon rap / ticking?