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Discussion Starter #1
Pulled the valve cover and seeing more build up than I'd like on the springs (N55). Everything else looks good. Figure it may not be good to douse them with brake cleaner and let that mix with the oil, but how else can I clean them? MVIMG_20190120_151443.jpeg

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Everything else looks good.
whoa.

What is the 'everything' else you've already inspected??

Any idea what led to this? Owned since new? Oil used? OCIs??
 

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02/2012 X5 35d M57Y CPO 99K miles NOKIAN WR G3 12K miles
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Pulled the valve cover and seeing more build up than I'd like on the springs (N55).
While unsightly, the function of the spring themselves will not be affected. The predominant presence of the ‘sludge’ on the springs and not so much on other nearby assemblies with less motion is interesting.
 

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Discussion Starter #5
whoa.

What is the 'everything' else you've already inspected??

Any idea what led to this? Owned since new? Oil used? OCIs??
What I mean is that there's no buildup on the moving parts, just the springs. Oil changes are regular at the dealership as called for. Just looking for advice on cleaning.

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Discussion Starter #6
While unsightly, the function of the spring themselves will not be affected. The predominant presence of the ‘sludge’ on the springs and not so much on other nearby assemblies with less motion is interesting.
I don't think the function will be affected, just concerned that some of the sticky stuff may dislodge and clog up a drain, etc. Rather dissolve it while I'm in there.

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Interesting...looks a lot like oil gelation. What kind of oil have you been using? What change interval? What was the longest interval? What climate are you in? What is your driving profile (short trips, etc)?
 

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I will say there are a lot of short trips, and we're in the cold Northeast. Wife's car, mostly shuttling kids around town. When the service light goes on I tell her to get an appointment, but can't say I've been proactive with that maintainence. Unlike my C5 race car and the E36 which get abused a lot more.

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While unsightly, the function of the spring themselves will not be affected. The predominant presence of the ‘sludge’ on the springs and not so much on other nearby assemblies with less motion is interesting.
I was wondering about this, too. My theory is hysteresis, metal being heated by repeated bending. Cut a piece out of a metal coat hanger, and then repeatedly bend it. It will get warm. Maybe these springs got just hot enough from hysteresis to sludge up any (old, weak, improper) oil that touched them. As they got insulated with sludge, they'd get even hotter... more sludge... more heat... more sludge... :dunno:
 

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The whole point of a spring is minimized to no hysteresis, else it would be a coathanger and not a spring for very long.

Fatigue limit, endurance limit, and fatigue strength are all expressions used to describe a property of materials: the amplitude (or range) of cyclic stress that can be applied to the material without causing fatigue failure. Ferrous alloys and titanium alloys have a distinct limit, called the endurance limit, which is the amplitude of completely reversed bending stress below which there appears to be no number of cycles that will cause failure.
The area of the SN hysteresis curve is merely entropy. Learn and practice E. T. Jaynes' Principle of Maximum Entropy - Max Ent. It is better to admit ignorance - maximize entropy - than to make a bad guess requiring many reiterations to overcome the minimized entropy answer space.

Oh, and theory =!= hypothesis.
 

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The whole point of a spring is minimized to no hysteresis, else it would be a coathanger and not a spring for very long.



The area of the SN hysteresis curve is merely entropy. Learn and practice E. T. Jaynes' Principle of Maximum Entropy - Max Ent. It is better to admit ignorance - maximize entropy - than to make a bad guess requiring many reiterations to overcome the minimized entropy answer space.

Oh, and theory =!= hypothesis.

Hysteresis occurs without necessarily reaching the fatigue limit or yield stress of a material. Go find one of those door stops that is made out of a spring so that you don't hurt yourself when you stub your toe on it. Bend the spring door stop and let it go. It will boing for a few seconds, and then stop, because of.... wait for it... hysteresis.

So, genius, what's your theory on how those valve springs got so sludged up and nothing else did? :p
 

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Discussion Starter #14
I would say dealership failed somewhere there.
Well we're not the original owners, bought as a CPO a few years ago. Regardless of the cause, I'm thinking of stuffing some rags under the springs to pick up overflow, then hitting them with brake cleaner. I can change the oil after to be sure that any contamination is minimized (more weight than I like to have on the lift but it's rated for 7000). Thoughts? Gasket arrives from ECS Wednesday.
 

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Well we're not the original owners, bought as a CPO a few years ago. Regardless of the cause, I'm thinking of stuffing some rags under the springs to pick up overflow, then hitting them with brake cleaner. I can change the oil after to be sure that any contamination is minimized (more weight than I like to have on the lift but it's rated for 7000). Thoughts? Gasket arrives from ECS Wednesday.
Couple thoughts.
- Do the next oil change yourself and make sure nothing goopy comes out of the oil pan.
- That buildup on the springs isn't going to cause any problems as long as that's the only place it exists.
- I'm going to speculate the previous owner didn't use synthetic and/or went way over the recommended oil change intervals.
- If you are there, I think it is fine to do as you are thinking...rag under the spring and hit it with some brake cleaner. Use your old toothbrush maybe. Use the red can stuff and not the eco-friendly green can. The red can stuff works a lot better. Any overspray or leakage into the oil will evaporate away anyhow.
 

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Well we're not the original owners, bought as a CPO a few years ago. Regardless of the cause, I'm thinking of stuffing some rags under the springs to pick up overflow, then hitting them with brake cleaner. I can change the oil after to be sure that any contamination is minimized (more weight than I like to have on the lift but it's rated for 7000). Thoughts? Gasket arrives from ECS Wednesday.


If you are not taking out springs make sure you use solvent specially made for cleaning internal parts of an engine.
Once you are done, get any synthetic oil regardless of weight and run it for few tens of miles. Take it out (filter too) and put in Castrol 0W40 that is available in Wal Mart. Run it for 3k. Take it out (filter too) replace it again with same Castrol and run it than 5-7.5k.
I think culprit here is long OCI, excessive city driving. N55 is direct injection and although it is better than N54, there is still fuel dilution. If previous owners neglected oil changes or if the used high sulfur gas, additives in oil probably depleted before OCI, which led to this.



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I would be WAY more concerned with oil sludge in places I cannot see, as opposed to focusing on getting the springs clean....

Was hoping edy would chime in. The whole engine needs the entire oiling system to be cleaned. His recomm has two very short oil changes, hope that this will allow the new oil to pick up some of the hidden sludge.

Love those CPOs. Just pays the money and be sure you have BMWs very best.....
 

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Discussion Starter #18
Thanks all for the advice. I'll go to walmart and pick up about 20 quarts of synthetic and try that plan. I have a feeling once strained that first cycle oil will be clean enough to use in the LS1, to replace the 2 quarts or so I burn every weekend.

To remove the gunk I can see, I'll probably use a can of seafoam applied with a brush.
 

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If you are not taking out springs make sure you use solvent specially made for cleaning internal parts of an engine.
Once you are done, get any synthetic oil regardless of weight and run it for few tens of miles. Take it out (filter too) and put in Castrol 0W40 that is available in Wal Mart. Run it for 3k. Take it out (filter too) replace it again with same Castrol and run it than 5-7.5k.
I think culprit here is long OCI, excessive city driving. N55 is direct injection and although it is better than N54, there is still fuel dilution. If previous owners neglected oil changes or if the used high sulfur gas, additives in oil probably depleted before OCI, which led to this.



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+1. good synthetic oil changes can safely clean sludge deposits over time. It may take a year but you don't want the sludge to come off all at the same time.
 

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Thanks all for the advice. I'll go to walmart and pick up about 20 quarts of synthetic and try that plan. I have a feeling once strained that first cycle oil will be clean enough to use in the LS1, to replace the 2 quarts or so I burn every weekend.

To remove the gunk I can see, I'll probably use a can of seafoam applied with a brush.


Get strictly Castrol Edge 0W40.


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