quote:
Originally posted by smeltjr:
not too many posts on the board about these. i have an acquaintance who has a 97 seville, 4.6 32v northstar, 90k. burns a GOOD quart every 1-1.5k. i have looked at some other sites and seems gm has a ring sticking problem on these amongst other leak problems-one person has gone so far as to say ring condition is worsened by an additive in premium fuel(?). questions are about arx, lube control, and using synthetic.
1. would arx help a sticky ring condition. either in regular cleanout or as a maintenance dose?
2. would regular dose of lc help the condition if it is rings?
3. what about an lc soak as i have seen recommended on saturns?
4. can regular dose of lc and maintenance dose of arx be mixed and used at same time-i have both.
5. would running synthetic help condition at all? yikes it holds 7.5 qts.
very nice, smooth, strong motor, but appears that gm has had woes with oil consumption and head gasket problems with these. looks like regular oil and coolant maintenance on these must be meticulous for these to last.
I've been told that the problem is identical to those in Saturns: weak piston rings with poor oil drain design. If that is the case, then my response to your points - based solely on the Saturn experience - is:
1. No. The rings don't just get "stuck" in the way 99.9% of people think of when they think of stuck rings: they get cemented into place with multiple layers of carbon that most things, including Auto-RX, simply can't touch when diluted to the level they are in 4-8 quarts of oil. In Saturn circles, there are stories of people pulling the pistons and spending hours attacking the rings
directly with a strong solvent and a brush, so no, nothing in a bottle will make much of a dent.
2. Depends on how long the rings have been stuck: some people claim that adding a regular dose of Marvel Mystery Oil or LC at every oil change can
prevent the problem, but most have little luck
reversing the condition once it's gotten that far. However, there are other benefits to adding LC that go beyond trying to free the rings: for example, with the rings stuck, you're going to get a lot of blowby, and the LC will help counter many of the detrimental effect of that.
3. In Saturns, repeated "piston soaks" seem to have met with some success. MoloKule has a good procedure for using LC for this. A lot of people use B-12 Chemtool or Seafoam for this. GM also makes a specific product for the piston soak (probably after reading all these boards and seeing what people were doing on their own). I don't have a part number, but I know they've begun to sell it over the counter at many Saturn dealers. I've tried several soaks using several different fluids, and it's reduced my consumption somewhat. I have yet to try the "MolaSoak," but I intend to: his procedure makes the most sense to me, especially the part about turning the crankshaft once by hand to make sure the fluid gets where it needs to.
4. I wouldn't do it, but I don't have any rock-solid scientific reasons for saying that.
5. No. Not at all, if the situation is indeed the same as it is for Saturn engines. Again, synthetic has other benefits beyond engine cleanliness, but using synthetic won't prevent this problem. It may keep you from encountering the problem at 40,000 miles as opposed to 60,000, but that's about it. Changing your oil and filter frequently won't prevent it either.
