My last car was a Subaru and they are known for catastrophic engine failures. I've had one, every one of my friends have had one. So I started doing oil analysis on each oil change. I just want peoples thoughts on how serious this is on the M113K engine.

Also, there was an oil sample sent at 122,000kms but it was damaged in transit

 

Hi. I religiously use Blackstone as well for all of my oil changes. My G55 has 142,000 miles and the reports have consistently been good. So yea, if I were you I would be concerned.

 

Thanks. Do you have any idea what I should be concerned about? Is there something I should do that might get me ahead of this?

 

Not this oil change but the last oil change I had put seafoam into the oil and driven 75km before the oil change to clean everything. I expected metal in that report (the one that was damaged in transit). This one however I imagined would be fine.

I don't see how these would affect anything but I did change the spark plugs, wires, and fuel filter in the same time period.

 

How long have you owned this car and how many oil analysis reports do you have?

 

Never put SeaFoam in your engine oil! It strips all the lubricity of your oil! Plus it loosens up old deposits and lets them run free... Right to your bearings! SeaFoam is awesome for cleaning out 2 cycle carbs... But that is about it! I'd be surprised if you didn't kill your engine. 75km with it in there??? WOW!

 

I have owned it for 2 years, from 100,000km to now 133,000km.
Universal Averages: Alu 18, Iron 25, Lead 4
1st report: Alu 10, Iron 14, Lead 2
2nd report: Alu 11, Iron 20, Lead 3
3rd report: Alu 32, Iron 42, Lead 7

 

So I went ahead and got both a compression test and leakdown test done. I did it with a friend, both of our first times doing it. I am an ex aircraft mechanic and he works at a tire shop. It is possible we may have done something wrong but I believe in our combined abilities.

Compression (PSI) / Leakdown (percentage) tests

1. 178 / 6
2. 182 / 3
3. 180 / 6 (air at exhaust)
4. 180 / 6
5. 175 / 15 (air at exhaust)
6. 180 / 3
7. 178 / 18
8. 180 / 9

Compression Results:
MB states want 130-174PSI, Minimum of 116PSI, and a maximum difference of 22PSI per cylinder.
My cylinders were a little high. Maybe carbon buildup creates a smaller volume = higher pressure? I'm not sure but I didn't think to worry about this.

Leakdown Results:
MB states cylinder leaktightness permissible total loss <25%, losses at valves and head gasket <10%, loss at piston and piston rings <20%
None of my cylinders hit the maximum of 25%. Cylinders 5 and 7 were close at 15% and 18%.
Sound at the exhausts in cylinders 3 and 5 meaning the exhaust valves may not be seating properly
I heard loud air noise through the oil reservoir at every single cylinder.
While doing a leakdown test, I checked using a borescope and found some that some pistons were very clean, while others were very dirty. I wish I documented the buildup of each but it was the end of a long day after doing a lot of other work. We also forgot to do the wet test by adding oil into the cylinders for 3 and 5.

Questions:
1. I heard you must use top dead center (TDC) during the compression stroke. I got a good reading from the first 3 cylinders which is statistically improbable so I tested on one cylinder TDC for 2 strokes. I got the same reading. Why does it state everywhere I must use TDC during the compression stroke only?
2. I heard air escaping from the oil reservoir from each cylinder, even the ones with only 3% leakage. Does this mean every piston/piston ring is leaking? Or more likely is this some kind of design of the engine? I find it difficult to believe they are all leaking.
3. Cylinder 5 has 15% leakage with air escaping out of the exhaust. This can mean that I have over 10% leakage past the valve/headgasket which is unacceptable in MB standards. How much should I worry?
4. So what now? This is all useful information for me to know but what can I even do with this? To replace the pistons and rings, or even the valves, I imagine this is basically a whole engine rebuild. So is there a point to do it preventatively? Because the cost to repair after failure would be the same as replacing them now (except for catastrophic piston through block kind of failure)


Thank you for reading. Please excuse my lack of knowledge as I am here to learn.

 

Hey Rick, thanks for your reply. I know there is conflicting arguments on whether safe to add seafoam into engine oil or not. I agree with you that it will loosen up old deposits and let them run free, but I believed that this would actually be good because I will drain the oil and get those deposits out. I would never add seafoam into a fresh oil change, this is just to give it a good *scrub* before an oil change. You make a good point about it possibly stripping the lubricity of the oil (it makes sense when you think about it) however their company seems to adamantly state this will not occur and I trust them.

 

I get it. I love Seafoam! But it has its uses, like anything else. Like I said, I'll use it in lawn equipment only. The tolerances there are already sloppy, so a little more wear won't hurt it. I've had a Stihl string trimmer that has run like a champ for the past 30 years... I flush it every few years with Seafoam... Not running it in the oil but spraying it into the carb several times... then one long one and then let it sit while the engine is hot. That cleans out ALL the crap and the carb loves it. It starts on the 2 pull every time and has for 30+ years.

However... The M113K engine is a hand-built, close tolerance, thing of beauty! I would never flush it with Seafoam or any other additive. Instead, I rely on BG products. I use BG MOA on every oil change and BG 44K in the gas about every 5k miles to clean out the injectors, valves, etc. I have had a relationship with BG for the past 35 years and have seen what it can do in person many times on engines... Both running and torn down to inspect after use. They are close to magical in my book.

Both products have their uses. There are professional engine flushes that are made to hook up to your engine and do all the work. That would seem a safer option but I would only do that if I had cause to. For me.... I'll run my engine out to 400k miles and all that stuff that has accumulated in the corners can stay there until then!

As for worrying... I wouldn't worry yet! You may have loosened stuff up and it went into your last oil check. I'd be curious to see what shows up on your results TWO tests from now. As for your compression test results... I would think they look fairly good as you are looking for commonality on results... And you have that!

 

Thanks Rick. Those are good reasonings, I will check out BG for future cleanings. I still have alot of carbon on some of my pistons and valves. This last result was the one after the flush, so the next one (which I am sending soon) will hopefully have less metal. Thanks for assuring me my test results are ok because I must worry more than most.

 

Compression looks good imo. Carbon buildup in the cylinder would not be enough to reduce chamber volume and increase compression.

Can you post borescope photos?

1. Compression and power strokes are the only times the cylinder is sealed. TDC on compression stroke means cylinder is sealed with the smallest volume, therefore easiest to carry out the leakdown test.

4. I wouldn't preemptively rebuild the engine. Worst case, if you have scoring starting, rebuilding (installing new parts) won't help. Replacing the block or installing sleeves is the only solution for scoring. With an engine this old, I would run it until you have symptoms beyond oil analysis. Do you have knocking, rattling, rough running, coolant loss or oil consumption/smoke out the tailpipe? I didn't see in this thread where you described engine operational problems.

 

The engine sounds great. However I have in the last 10,000km started experiencing oil consumption. Recently 1L after 3000km. No other issues to date.

Sadly I did not take many photos but here are the couple I did. I would say 3 pistons looked clean like this one, 4 were fairly dirty, and the dirtiest one is shown below.


Cleanest piston

Dirtiest piston