Normally the basic application is sufficient to free up stuck piston rings contributing to the oil burning in these motors. However, with that said, it is likely that you have an 8 quart oil pan on your Northstar motor. At least the 1998 version that I owned.
Therefore I would suggest adding 1 ½ bottles of Auto-Rx to crankcase for the initial cleaning phase. After completing the cleaning phase and the rinse phase, I would highly recommend running the maintenance dose. That would be adding 3 fluid ounces or ¼ bottle with each or every other oil change.
The maintenance dose was helpful on my 98 model in keeping the consumption down I would also check out the performance of the PCV valve on your unit. A stick valve can also cause excessive consumption.
This was originally my question, and I intend to put more information down on this thread so that others can learn from my experiences. I have another thread over at the cadillacforums if anybody wants to look it up, but here is the gist in a nutshell. The girlfriend bought the 2000 Seville SLS last spring and it had been consuming some oil. I didn't know how much, but then I decided to use a can of seafoam in the crankcase. Oil consumption went up a ton after the seafoam treatment! Then I started trying to fix what the seafoam treatment had made worse. Other things I had done is recently replace the PCV valve, and also removed all of the spark plugs and did a direct pour with GM top engine cleaner in an attempt to loosen carbon on the piston rings. Before the cleaning, consumption had been in the 300 miles per quart area. While it never smoked, when the consumption was this high, the exhaust had a significant oil odor to it. After the top engine cleaner, I was in the 400-500 miles per quart area. I just added Auto-RX last week, so I haven't given it much time to work, but I will be updating this thread as things progress. Here is a tidbit from the other forum regarding where things stand...
I've been doing some researching and driving. So, as we recall, I was somewhere just south of the 300 miles per quart consumption level. As I started using the accelerator pedal as a footrest (commonly helps Northstars), I've managed to get close to 500 miles per quart consumption lately, now on dino Rotella-T (10W-30) for the last two oil changes. Last week, I ended up doing the recommended GM top engine cleaner (couldn't find the better old stuff, but I used one green two cap bottle per bank) method per the TSB. I even fashioned a real sweet angled probe to suck out the fluid from the combustion chambers through the spark plug holes. I did a compression test prior to the top engine cleaner treatment (hot, per instructions), and here's what I found: The cylinders (PSI) are in order from 1-8: 175, 170, 170, 165, 175, 160, 175, 180. Following the 2.5 hour soak time, I proceeded to extract the top engine cleaner. It became apparent that the three lower cylinders- 2,4, and 6 turned that top engine cleaner dark nasty brown upon vacuum extraction. After buttoning it all back up and doing a runup (in the process killing the already frozen Minnesota mosquitoes due to nasty plumes of whitish smoke from the cleaning chemicals), I changed the oil. This time I actually put 7.5 quarts in instead of the customary 6.5 (one quart low on a Northstar) to help buffer the remaining top engine cleaner in suspenion until the next oil change. I didn't find any nasty chunks or anything in the oil pan, and I cut open the filter, which did show some carbonesque particles trapped within. I immediately put about 130 miles on it in one highway drive after the decarbonization and put it through heck with both positive and negative force on the pistons. So far, we've put about 500 miles on it and the oil is already dark! It has been running very smoothly, although consumption is not accurately measured at this point. I can still get a tiny whiff of that cleaner mixed with a bit of oil at the tailpipe, but it is definitely improved. Prior to the procedure, once the engine was warm, you could definitely smell a good hint of burning oil (although never any smoke). The girlfriend will be driving about another 500 miles on it and I will do another oil / filter change. I'm kind of fascinated to see if this will improve the oil consumption characteristics.
The oil consumption has not been measured over the past week since Auto-RX was added, because she hasn't been putting enough miles on it. Plus, from what I understand, oil consumption may not begin to diminish until well into the rinse cycle. If anyone else has had any dealings with a thirsty Northstar, feel free to chime in!
I did this because I intend to keep with the 4-6 quarts of sump capacity per bottle. I intend to run two clean and two rinse phases and then immediately start the maintenance doses. Most Northstar people seem to run the 7 quart sump between 6 and 7, so I don't see it as being a huge deal. Plus I expect it to eat a bunch of oil, which will necessitate adding more auto-rx over time, especially during the first clean and rinse cycle.
-- Edited by love0126 on Monday 13th of February 2012 02:21:19 PM
-- Edited by love0126 on Monday 13th of February 2012 02:22:18 PM
Your engine calls for so many quarts of oil (8 i think) since Auto-Rx is not an oil your not overfilling your oil reserve. The only function oil has is to carry third party contaminants etc to the filter. Please use the proper amount of oil. Auto-Rx is a cleaner not an oil.
Ok, so 2 ounces per quart. If you read my methodology, my ratio is exactly correct. I'm using 6 quarts of oil to 12 ounces of auto-rx. So how is adding 18 ounces of auto-rx to 7 quarts of oil (per your instructions at the top of the thread) that I'm using an incorrect dose. Let's do the math. 2oz * 6 Qt=12oz auto-rx. The sump is in the full range, so I do not see how this is improper. Using the 7 quarts of oil and 1.5 bottles of auto-rx above, we have actual ratio=18 ounces auto-rx/7qt. Solving for the actual ratio yields 2.57 ounces per quart, which violates the correct ratio.
Yeah, I see the response. I am starting this thread with the hope of allowing other Northstar owners knowledge of the efficacy of Auto-rx on Northstar based piston ring carbon. I will continue to update this thread all the way through the rinse phase. As far as methodology, I am using one bottle and have my sump underfilled to 6 quarts.
The sump is 7 quarts per the owner manual plus the pint sized oil filter. I don't see how the ratio of 6 quarts to 1 bottle of auto rx is less motor oil proportionally than 1.5 bottles of auto-rx to 7 quarts of oil. To me, this makes no sense.
The ratio of Auto-Rx is 2 ounces per quart of oil & 7 quarts calls for 14 ounces of Auto-Rx. Each bottle of Auto-Rx holds 12 ounces. If you continue to choose to make up your own application than you take the responsibility for the results. Auto-Rx is patented chemistry ( i am the inventor) it is formulated to work on the ratio i have already stated.
This is Franks post he is not saying 18oz he is saying 14oz.
Daryl
The ratio of Auto-Rx is 2 ounces per quart of oil & 7 quarts calls for 14 ounces of Auto-Rx. Each bottle of Auto-Rx holds 12 ounces. If you continue to choose to make up your own application than you take the responsibility for the results. Auto-Rx is patented chemistry ( i am the inventor) it is formulated to work on the ratio i have already stated.
Frank in the very first post of this thread says 1.5 bottles of auto-rx to 8 quarts of oil, which is definitely above the ratio as purported above as the optimal ratio. Regardless, the application must have some flexibility as the website says 1 bottle of auto-rx is fine with 4 quarts of oil. But my contention is my current ratio is spot on, thus there is no deviation from accepted usage, from what I'm being told.
