Oil analysis suggests stuck rings. How bad is it?

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Nov 13, 2011
I have a 20hp Vetus diesel (Mitsubishi) in my sailboat that sees about 65 hours of use a season. The motor has been burning a oil the last couple of seasons so I'm trying to figure out why. Here's my history with the motor. 2009 - First season with the motor for me. Motor is 10 years old but low hours (less than 500). Seems to run well, no oil consumption noticed for the season. A season is about 65 hours for me. 2010 - The guy who did some maintenance (me) on the cooling system failed to properly replace all the coolant. Engine overheated 15 minutes after launch. How hot?? Don't know. No temp gauge, the warning buzzer went off. Engine was shut, added more coolant and away we went. Changed oil just in case. Engine seemed to run fine, though seemed to hard to start when cold and burns oil. Engine burned 1/2 to 3/4 quart of oil through the season. 2011 - Still burning oil, slightly sooty transom. Burned 3/4 to 1 quart of oil during the season. When putting the boat away for the winter I collected some oil and sent it to Blackstone labs for analysis. Shows high wear in metals aluminum, chromium and iron. Lab suggests a stuck ring. I guess i'm tossing this out there to see if anyone has any suggestions on what to do. I've not had a compression test done. I don't own a tester and don't have access to one. My boat yard does not have one. I know..I should figure out a way to have it one. I've been reading about little tricks to free a stuck ring like Marvel Mystery Oil/ATF or Seafoam additive. Could stuck rings affect compression? I'm wondering if I ran a compression test, then soaked the rings in some additive, then tested again I may have some data that would suggest that the additive is helping? If it is indeed a stuck ring, I'm thinking that sounds plausible since the overheating could burn the oil around the ring to "stick" it? Here is my oil analysis results: What I really need is a compression tester. Harbor Freight has one for $25! I wonder how [censored] it is?
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If it overheated, and is putting metal into the oil, then I'd think the bores are trashed. If it was me, as long as it starts, I'd run it. I don't think you're chugging through oil at a rate to worry about runaway. Maybe do a few short OCI's, to help flush out the motor. But I'd also start shopping for its replacement if after a few UOA's don't show metals coming down. Those additives for unsticking rings is for rings stuck by gunk. I don't think you have gunk in those rings from one overheating event. Possible, if it got hot enough--but I don't think those will help.
Although that oil use doesn't seem excessive, you're only guessing about the rings/head gasket unless you do a compression check. That HF compression tester will be fine - not only are you looking at what average compression is but also the max difference in compression between cylinders. OCI - Oil Change Interval
Sorry, used to a different forum; and I see you're new(er) to this oil game. OCI = oil change interval UOA = Used Oil Analysis
Let me offer a very easy "inexpensive try it and see" solution. Try some Auto-RX if you believe the rings are stuck. I had a very similar experience with stuck rings in my old 1996 Taurus Vulcan 3.0L engine due to an overheating event. I thought the engine was trashed. The compression on two cylinders was horrid. I used two applications of ARX (two separate clean and rinse cycles) and the rings were liberated, and I validated that with compression testing. Here is the whole story in case you need details: first application and details of event http://www.bobistheoilguy.com/forums/ubbthreads.php?ubb=showflat&Number=1128803&page=1 and here is the second application and final results http://www.bobistheoilguy.com/forums/ubb...rue#Post1273037 ARX certainly proved its worth in my situation. If your rings are coked, it can work for you. Just make sure to follow the directions and don't get impatient. It's made to work slowly and not overnight. Try ARX first; it's a LOT cheaper than any teardown, etc. Worst case scenario is that you're out a bit of money before having to remove and rework the engine.
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dnewton3 I like your idea. Before I do anything I'll get a compression tester so I have metric to gauge any progress I may make. Looking into Auto-RX now..
Given your typical use factor of approxiamtely 60 hours a year, you'll need to run about 1/2 year on the application phase, and 1/2 year on the rinse phase. It will take the whole season to see if any improvments can be made. Don't get "fancy" and try to bolster the ARX effect with synthetic fluids, other additives, etc. Just stay the course, be patient, and you'll get your answer. Get a compression tester; any HF unit should suffice as long as it has the correct adapters. I'm not promising ARX will solve your problem, because you may or may not have true mechanical damage. ARX will NOT restore damaged metal surfaces or worn seals. ARX WILL clean combustion byproducts from metals and liberate seals and rings to do their job. If you read my two posts regarding my experiences, you'll understand the entire philosophy. What I'm stating is that it's a LOT cheaper to try ARX (even two clean/rinse phases) than it is to yank a motor and have it rebuilt. All it takes is a little money and patience. Please post some follow up info when you get the time. Would like to know the compression reading pre and post application and rinse.
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I also would recommend the Auto-Rx...great product...I have had great success with it in two engines with severe oil burning...a '92 Honda Prelude and a '02 Nissan Pathfinder. Follow the instructions religiously and you may be in luck if the sticking is due to deposit formation. It is worth a try in my opinion.
As long as you don't already own a compression tester, look for a cylinder leakdown rig. You put air pressure into the cylinder and watch to see how much leakage is occuring. It helps you identify the source of the leak (rings, intake or exhaust valves). Most tool peddlers can get them (Mac, SnapOn, Matco).
Diesels don't like to be overheated. It got real hot and one or more of the Aluminum pistons expanded untill it closed up the clearance between the piston(s) and cylinder wall. Basically it began to Sieze which spit the metals into the oil and the rings lost some tension.
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