What additive helps get rid of carbon

[mechanicx]

Originally Posted By: crazyoildude
Im have used mmo for over 25years great stuff problem is these northstar engines leak oil and that would increase the leak and besides what will that do for carbon in the combustion chamber?


Well cleaning carbon in the combustion chambers is what the Techron is for. I wouldn't be so sure a Northstar would have bad carbon build up on the pistons. GM also offers a top engine cleaner for carbon. As far as a potential oil leak, true MMO will thin the oil some but it has seal conditioners in it too, plus this should only be a temporary problem.

 

[mechanicx]

Originally Posted By: crazyoildude
it could have piston slap but i don't think so sounds like a bad belt tensioner but it is not


Sometimes a bad engine mount makes a rattle noise. Does it change from park and drive or neutral or no? Could also be timing chain noise. I think a timing chain doesn't usually get louder with engine revs where as piston noise might.

 

[demarpaint]

OP See if you can get a hold of the old formula GM TEC (Top Engine Cleaner) IIRC, it was made for carbon problems and might help.

 

[Kruse]

Originally Posted By: ADFD1
Originally Posted By: dickwells
Put water into a northstar and someone will be buying a new engine.


Have you done it in a Northstar engine, and ruined one? I've done it a few times in different used cars I bought and it worked out well. But I was supervised by my uncle and he showed me how to do it.


Northstars (and a few other "modern" engines) have some intake runners that twist all over the place and have some low spots.
If you put water down a Northstar at idle, it will pool up in some of these runners. When you suddenly open up the throttle, it will take in a huge gulp of water. Be very careful trying to break up carbon on a Northstar using the old ingesting water trick. It can be done, just not at idle.

 

[mechtech2]

If it is spark knock that you are hearing, I'd use a strong concentration of Chevron Techron or Redline S1 in the gas tank - then fill it.
Then drive it until it is almost empty.
But who knows what the sound is that you are actually hearing?

 

[crazyoildude]

I dont really know either all i know is sometimes its not there at all and sometimes it sounds like a bad belt tensioner or as the cars owner said sounds like it has a ping pong ball inside..
If you listen at the oil pan it sounds like all the rods are bad bit my northstar sounds the same way it sounded that way since it was new...I think i will try the techron and i was thinking to run some sea foam through the pcv valve..

 

[1993_VG30E_GXE]

Originally Posted By: crazyoildude

What about sea foam??


This is after seafoam:

 

[1993_VG30E_GXE]

The next ones are after a manual cleaning with Varsol & Engine Cleaning Gun, then Laquer Thinner

 

[1993_VG30E_GXE]

Nothing too outrageous, but the point is I think it may be at the point where cleaners could be a waste of money, unless there's no way you can overhaul it - then try it.

I found that the cleaners in fact clogged the car somehow - after I did the top end treatment with the seafoam, the car almost stalled numerous times at stop lights the day after.

Don't think I'll be using it again.

 

[saab93driver]

Originally Posted By: crazyoildude
OK so car in question is a 95 Cadillac and it has the northstar v8
Car has 44000 original miles (old lady miles) really! engine has a knocking sound but im pretty sure it is carbon buildup, what additive can i put into the gas tank to get rid of the carbon it belongs to a neighbor and i want to try and fix this without taking the motor out.
I believe the problem is carbon because the knock is not always there and sounds like a bad belt tensioner sometimes (its not) and you can hear it cold more than hot.. Car has never seen over 60 mph...those northstars love to open up..
What about sea foam??


You might check for a shop that uses BG products and ask them. BG has a machine called a Squid that is an active combustion chamber cleaner. I have only read about it, no experience, but it has been around for a while and looks interesting and a non invasive way to actively decarbonize.

 

[mechtech2]

We have to find out what is the problem.
What the noise is.
Spark knock or a mechanical component.

 

[crazyoildude]

i know i will have the car at my shop this week and look for the problem... It is my neighbor and she is asking me all the time... She is a senior and a good neighbor so i really want to help her but i just dont want to have to take that engine outunless it gets really slow

 

[JohnBrowning]

Well you would have to put an awful lot of stuff in the fuel to clean heavy carbon!!! I would use Redline Si-1 but some how I doubt you will since it is difficult to find locally inmost places! Nothing else you can buy OTC is as concentrated. My second choice would be to go to a Toyota dealerships parts department and ask for Toyota brand fuel injector cleaner int he small silver gray metal can's. The Toyota stuff is very strong. Add two cans to the fuel and have them fill up and drive that until it is down to 1/4 tank before they refill again.

Seeing how it is a N.Star motor the first thing I would do would be to either add two bottles of Auto-Rx or Add two quart of 5 minute engine oil flush and run it for 30-45 minutes! Most of the N.Star's problems are from dirty rings so even if you get rid of the carbon if you do not get the rings clean you will not see much improvement. GM in my area routinely did the injector service free of charge on most of the N.Star engines about every 30K miles to keep customers happy because of the carbon and ring issues. It would by default clean the rings enough to make the car run like new and stop using oil temporarily.They normaly wrote it up as de-carboning but in reality their was little carbon at all in the combustion chamber they just did not have a good way of getting at the rings directly. Some Dealerships tried solvent engine flush machines but GM would not pay for it under warranty like they would the injector and EGR cleaning service.

 

[Vizzy]

Putting solvents of any kind directly into the NorthStar oil crankcase is asking for trouble.

I would recommend doing several oil changes using a HDEO oil like Shell Rotella T or similar...avoid the MMO!!!!!


The best for decarboning is to use a PEA based detergent in bottle form AND a intake cleaning system like the 3M product..safe and impossible to hydrolock the engine this way.

Any product with PEA based detergent is the only proven way to get rid of carbon deposits without leaving residue of the detergent behind afterwards!. Only PEA does this!