: Cleaning your engine of evil carbon



eldorado1
09-13-05, 10:36 PM
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
09-14-05, 10:16 AM
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
09-15-05, 07:12 AM
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
09-15-05, 04:31 PM
Another Seafoam user here. I use it on all my car's and outboard engines :thumbsup:

mikes93sedandeville
09-15-05, 09:04 PM
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
09-23-05, 05:04 PM
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
09-29-05, 08:35 PM
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
10-05-05, 12:23 PM
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
11-07-05, 12:24 AM
i have heard that you need to vacuume it out after it soaks is this true

eldorado1
11-07-05, 12:49 AM
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
11-11-05, 12:49 AM
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
11-12-05, 11:47 PM
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
02-05-06, 02:14 AM
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
02-05-06, 08:52 PM
I'm not sure what you're SUPPOSED to do :eek: , 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! :cool2:

mtflight
02-06-06, 01:50 PM
I'm not sure what you're SUPPOSED to do :eek: , 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! :cool2:

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?

Cadillacboy
02-08-06, 02:57 PM
I guess the story of cleaning carbon deposits are all wrong for the following instructions .What I know is that hit from 30 up to 80 MPH with the engine getting red line and then after hitting 80 MPH, let the car slown down to 20 MPH and then as soon as you get 20 , step on gas pedal till you see 80 on the speedometer .Repeat this 3 times in a month .....
Well, I also think that the very best way is to use a professioal lengine cleaner

mtflight
02-08-06, 03:07 PM
Top Engine Clearner: update
I performed the TEC carbon cleaning last night. With the engine idling, I sprayed it in the PCV hose... unplugging the vacuum hose made the car start to run rough.

I sprayed about 90% of the bottle in, and then thecar stalled when I plugged the hose back in.

Turned the car back on, and raised RPMs to ~2000 until the white smoke began to come out.

This morning I cranked her up, and raised RPMs to 2000 and so much white smoke kept coming out forever, and ever. I think I may have startled other neighbors--some lady got on her cell phone, or maybe she was already on it.

Easily a cloud the size of two 3 story buildings. Wow.

I then went for a brief drive to the dealership with a coupon for a $22 oil change. On my way I put it in 2nd and raised it near redline, then let the engine slow down. I did this twice--and no smoke or anything came out.

I got my oil change, then repeated the 2nd gear to redline, and engine braking down to 30 on my way in to the office.

Clean as a whistle.

The engine sounds crisper, more mechanical--top of the engine still has ticking sounds which are likely normal valve/cam sounds.

Tailfin
03-16-06, 08:52 AM
Hmm I keep thinking I have this stuff down, and then having second thoughts. I pour right into the TB, but basically going to the same place. How do you guys get so much smoke? lol... I poured it in until it was just about stalled, and then I finally got THICK white smoke for a bit...I turned it off then, poured a tiny bit more in, and started it up 20 minutes later. I got white smoke for a half minute or so, but it wasn't really really thick, or enough to create a huge haze or building-high cloud like I notice others seem to get.

Maybe my engine's too clean but I don't think so. I've done this with 2 cans of GM TEC and 3 of SeaFoam, and each time I still get more white smoke. Just wondering why I can't seem to get the "forever and ever" smoke...but I don't understand how one would get that anyway, because eventually the stuff's gotta burn off.

I noticed water mentioned too to steam clean it. I was just thinking of a happy medium here....would not be free, but dirt cheap compared to the cleaners... How about doing this with a load of plain isopropyl aclohol?

mtflight
03-16-06, 01:10 PM
Hmm I keep thinking I have this stuff down, and then having second thoughts. I pour right into the TB, but basically going to the same place. How do you guys get so much smoke? lol... I poured it in until it was just about stalled, and then I finally got THICK white smoke for a bit...I turned it off then, poured a tiny bit more in, and started it up 20 minutes later. I got white smoke for a half minute or so, but it wasn't really really thick, or enough to create a huge haze or building-high cloud like I notice others seem to get.

Maybe my engine's too clean but I don't think so. I've done this with 2 cans of GM TEC and 3 of SeaFoam, and each time I still get more white smoke. Just wondering why I can't seem to get the "forever and ever" smoke...but I don't understand how one would get that anyway, because eventually the stuff's gotta burn off.

I noticed water mentioned too to steam clean it. I was just thinking of a happy medium here....would not be free, but dirt cheap compared to the cleaners... How about doing this with a load of plain isopropyl aclohol?


I think you're not referring to a Northstar. These instructions are specifically designed for the Northstar. Spray it in the PCV vacuum hose, car will begin to run a little rough... keep spraying until the can is gone.

AFTERWARDS, accel to 2000RPM until you see the smoke--then you turn off the car. I left mine overnight. In the morning, the cloud formed, again by accelerating to 2000 RPM.

Tailfin
03-16-06, 04:26 PM
Yeah I realize they were for N*...does it really build up THAT much more carbon than other engines though? It just seemed like it never got all of it out...as I can add another can and still get more smoke. I'm thinking I might try the isopropyl method...or at least do that after the water method...would ensure getting the water out.

Ranger
03-16-06, 06:39 PM
I am not sure if the Northstar builds up more carbon or not. I believe it is more sensative to it though.

Beefmalone
03-16-06, 06:40 PM
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.

what about the older ones?

mtflight
03-17-06, 11:40 AM
Yeah I realize they were for N*...does it really build up THAT much more carbon than other engines though? It just seemed like it never got all of it out...as I can add another can and still get more smoke. I'm thinking I might try the isopropyl method...or at least do that after the water method...would ensure getting the water out.

The smoke is not carbon. It is the solvents evaporating under the heat of the combustion chamber.

Leaving the solvent/vapors inside overnight is what insures that you dissolve the most carbon.

I think the situation with the Northstar, is that it was designed to be a high performance engine, and it is mostly underutilized in that role. So either it is more sensitive to the carbon or it builds more due to it's underuse.

Tailfin
03-17-06, 01:59 PM
Hmm, then is there any way to tell if you've got most of the carbon out? Don't say take off the heads :rolleyes:

mtflight
03-17-06, 07:31 PM
Hmm, then is there any way to tell if you've got most of the carbon out? Don't say take off the heads :rolleyes:

I'd say that if you did it properly, that should give you the peace of mind.

I think there is a way to look inside the engine with a borescope through the spark plug port. Don't ask for details, I haven't done it.

Ranger
03-17-06, 10:38 PM
Yes, you can . I have one and have done it but you'll only see the top of the piston, not the underside of the head.

FredMaxwell
03-19-06, 04:45 PM
Can I ask,
How come seafoam costs $5 a can if it's mostly rubbing Alcohol?
Good lord, for 92 cents you can get a bottle of 91% Iso

I buy the 50 cent bottles of 50% because it is a great way to wash your hands


Also, I always thought Alcohol would dry out your cylinder walls and rings.. what is the story?

PS: That TEC sounds like some good shit.. where do you get it?
Is that what they use in injector cleaning machines?
Or is it that can you run your engine off of to clean the injectors?

Tailfin
03-19-06, 06:43 PM
I also had to ask where to get it...at a reasonable price anyway. Just go to the nearest place you'd take your car that's an official GM Dealer, ask their parts section. Only about 7 bucks.

I was wondering about the isopropyl too. I also wonder if you can put GM TEC in the fuel in order to give the injectors a good blast...but I ain't gonna try it unless I'm reassured it's fine. Not sure what those chemicals would do to the pressure regulator and such. :hide:

Zorb750
03-19-06, 07:38 PM
Probably wouldn't hurt it if you did it once in a while. I'm going to look into it myself and get back to you about that one.

AnotherToothpick
03-26-06, 01:12 AM
Where would I find the PCV tubes in a 4.9 engine (taking into account that I still have very limited knowledge of where everything is and what it's called)?

Also, does this process more or less have the same effect as adding carb cleaner to the TB tubes? I poured half a can of CC into the TB tubes while rodding them out, then let it sit in the engine overnight before starting it the next day and burning it all off... Unfortunately this did not solve my rough idle (800-1000rpm) or my sporadic knocking. Though I gather the rough idle could simply be the result of me needing a new O-ring throttle body gasket.

Tailfin
03-26-06, 04:28 AM
The PCV tube runs right across the front valve cover. There might be a beauty cover on top to remove first (mine has always been missing lol). The PCV valve is on the right side (saying all this looking under the hood, not from the driver perspective). The tube comes out of the throttle body on the left side of it, towards the front a bit, and it's larger than the other vacuum tubes on that side.

I would say it's similar to the carb cleaner procedure you performed...except that stuff isn't nearly as robust as GM TEC. Seafoam might be another story. I personally pour the GM TEC right into the throttle body blades, while holding the throttle slightly open as necessary. This makes it easier to pour it in at a controlled rate (or so has been my experience judging from the engine behavior). I also noticed by doing this, it acted as carb cleaner only much better, and from what I can see, it nailed the intake manifold as well. Carb Cleaner is good to hit your EGR tubes with though...and I also pour some GM TEC down in there and let it soak so the EGR passageways get a good cleaning. Just always be conscious of that hydrolock issue.

AnotherToothpick
03-26-06, 11:19 AM
I apologize for my complete ignorance, but...

If I were to pour TEC into the throttle body to clean the engine, should the car be idling or off? If it's all the same, should I run the engine to 2000rpm and follow all of the other procedures drawn out for the PCV method? Would it be more effective to spray TEC into the PCV or to pour it into the TB (or no different)?

Sorry to be a pest...

Tailfin
03-26-06, 12:47 PM
Don't worry, if you don't know something, the only way to find out is to ask.

The engine should be running... Yes, the rest of the procedure should be the same as has been mentioned on here.

Pouring it in via the throttle body is just something I did...It might be mentioned before on here, but I haven't seen it. The reason I say it's more controlled is the PCV will take it right in past the blades, which is why you have to be even more careful about pouring it in slowly. It's also just physically easier than getting it into a vacuum hose. I hold the throttle arm just slightly so it revs a wee bit. That way, I can pour a little more without stalling it. The only time the engine should be off when doing this is letting it soak after it stalls or you turn it off for that purpose.

The reason you don't want to pour too fast is hydrolocking the engine. On the intake stroke, the intake valve opens, and it sucks in air, and if you're pouring it in, GM TEC or whatever... Then both valves close, and the compression stroke occurs. If there's too much liquid in the combustion chamber at this time, it will try to compress the air/fuel mix and because liquids don't really compress, it will be unable to do so, and that can cause some nasty engine damage. Instructions indicate you can pour most of it in...then pour the rest in just enough to stall it... That way, it cooks the carbon off as it sits in there. I've always chickened out on actually stalling it lol..but that's what I meant by be aware of hydrolocking whenever you're introducing any liquid into the engine.