Dave51

You're Canadian, eh?

rzldzl

you betcha

third coast

I want to take a minute to minimize any misconception regarding the potential value for oil analysis in general and the worth of a diluted sample. True, if the sample is significantly diluted this will result in some error. The question is how much error and is it significant. When the sample is prepared by the analysis lab a very specific amount of oil is drawn and diluted with a specific solvent before it is tested. Blackstone has used 1 part oil and 8 parts solvent. As a result, error due to dilution in the sample taken from the engine is reduced by this 1:8 factor when the sample is tested. Even assuming Dave’s proposed 40% dilution of oil by antifreeze in the engine the sample as tested with 8 parts solvent added the concentration would be more like 5% off. A few percent error is insignificant when looking for several times greater wear metals from averages. If you tell the test lab about potential dilation they may take that into consideration when providing a summary.

As discussed this particular situation may not be the best case for a one-off oil analysis. If there is visible metal flakes (glitter) in drained engine oil it is serious. I would call that a show stopper for that engine. It indicates very heavy wear and a filter that likely went into bypass due to being plugged with contaminates. I have experienced this situation first hand on another vehicle (not a Jeep 4.0). If no obvious wear debris is seen in the oil sample analysis can be part of the overall evaluation process.

Oil analysis is most useful when performed at routine intervals and results evaluated for a change in the trend. This will alert you that something has changed from normal wear rates for that engine and an investigation can begin before something becomes catastrophic. It only takes a few minutes and is very easy.

Even a first time oil analysis is valuable. Based on an oil analysis I was able to identify a cracked head on my 2000 4.0 before it showed any obvious symptom. Analysis identified elements of antifreeze in the oil and slightly elevated wear metal. Based on this I investigated and discovered a small crack in the 0331 head. It appears that the head problem was caught early before serious engine damage occurred. Future oil analysis will help confirm. On a ’91 Cherokee I did an oil analysis before I bought it and that identified an oil dilution by fuel. That type of info is very valuable when making a purchase decision and in determining a fair purchase price.

I have found oil analysis useful enough that I have begun performing an oil analysis every other oil change on most of my vehicles to establish a baseline and look for problems. I would likely not buy another used vehicle without getting an oil analysis first if at all possible. As an FYI I have no connection to Blackstone Labs or any other analysis lab.

third coast

Dave: thanks for the correction and info on cam bearing lubrication. The situation I was thinking about but misstated is with the cam lobes and lifters. Somewhere I came across info that indicated cam lobes can take a beating in the area of cylinders 3 & 4 in the case of a 0331 head crack in that area. This is possibly due to oil returns near the typical head crack location dropping high concentration of antifreeze onto the cam lobes. If anyone can confirm this it would be nice. I know on my cracked 2000 head there was a small stain apparently from antifreeze that headed to oil return holes in that area.

Fortunately if the head is off it is relatively easy to pull out the hydraulic lifters and inspect them. The surface of the lifter that runs on the cam should be smooth and have a slight convex surface. In my case they were like new.

Thanks again for the info on engine lubrication paths.

Dave51

OST, I believe you could make the numbers work with no error at all, but not for the above (keeping in mind with only 1200 miles on that oil, I'm really not seeing what that would tell us about wear, we're more concerned about damage over the last 150 miles or so).

If Blackstone dilutes the oil by 1:8, they would multiply the measured value by the amount of solvent added to get the final concentration, i.e., let's say lead is 200 ppm cause we might have bearing wear. The sample you send is 100 ppm cause it was suddenly diluted by half (trying to make calculations easy as I am short on math skilz). So they dilute it with a known quantity of solvent, centrifuge the sample to extract the insolubles and multiply it by 9 and we're right back where we started from at 100 ppm.

However, if they found 50% antifreeze you could extrapolate that out and come up with 200 ppm again.

What would be very misleading would be a normal sample (which based on the view of that dipstick is what I would bet)(if someone wants to send Uriah $30). Best answer IMO is pull the pan, examine the bottom and take a look at a couple of rod bearings.

See close up, I'm really liking this, cautious optimism:

Uriah_P

Hey guys, sorry for the long delay in my response. Been really busy this past week and haven't had a chance to get too much done but here is an update. I will attach pictures below as well.

I changed the oil and oil filter, and have about half a gallon of it stored in a clean container so I still have the option of doing a test with that. I think at least 7 quarts drained out, and from what I can find it sounds like that's at least 1 quart too many. It filled my 7 quart drain to the brim, and I actually needed to poor some out towards the end because I thought it was going to overflow, which it probably would have by just a little bit.

After pouring about a half gallon into the clean container, I let the rest of the oil sit for a couple days in the pan with the idea that if I did so I could slowly poor the oil out and have any metal fall to the bottom. So after I did this I looked closely at the drain pan and unfortunately it did appear that there was not only clearly some coolant in it, but also some metal pieces as well. It looks to me like super super fine sparkles in the sunlight, although not a ton of them but more than I wanted to see. I also found a few larger pieces which were a little concerning as well which I'll add pictures of. What do you think of this and is it even worth it to continue working on this or does this indicate serious damage?

I also went ahead and rented a compression test kit and watched a couple videos but I wanted to double check here before I actually use it.

I took the distributor bar off, and pulled all the spark plugs and have them organized with cylinder numbers (with the one closest to the radiator as number 1 - wasn't sure exactly if that was correct or if that would actually be 6).
1-3 to me look a bit dirty/rusty while 4-6 were definitely noticeably cleaner (see pics)

I wanted to double check before I try to crank the engine though if there is anything I am missing. I looked up that the fuel pump relay should be pulled out, so I located that in the fuse box but I haven't actually taken in out yet. I also read somewhere that I need to have the throttle blocked wide open, but I do not quite know what that means or how to do it, I think I was looking at a wrangler video for that piece of info but I wanted to see if that was something I should do and how I would do that.

Are there any other steps I should take? I plan on pulling the fuel pump relay, attaching the compression test and starting with cylinder 1 and working my way back, turning the key 6 times per cylinder. Does this sound like the correct way to do this? If they all come back between 120-150 psi with a variance within 30 psi does that mean the engine should be ok? And if not does that mean I should just stop there and accept that it'll need a new engine altogether?

Thanks again for all the help in advance, here are some of the pictures:















I

Dave51

Yeah, that might be the deal-breaker. If that came out on a normal drain there could be a lot more of that in there.

Next drop the pan. It's pretty easy and good practice. My guess is it's one of those rod bearings we were gonna look at.

OTOH, I guess we are...

Dave51

On the bright side, a couple of those plugs might be a little cleaner than expected, but not earth-shattering!

Uriah_P

Darn.. I wish I had done that before filling up back up with new oil haha. Do you think I should do a compression test still or should I just put it back together, drain the new oil and pull the pan?

Lets assume that there is more metal where that came from in the oil pan, is that going to indicate more damage than is worth fixing?

I am just trying to figure out for now if there is a chance I can save the engine with a new head, or if I should just plan on saving up for a whole new engine.

Dave51

We're really kinda at snowball's chance, but looking is free. Still have the old filter? Cut it apart and see what'she in there. That oil is no good and don't turn the engine over. Assess what's in the bottom of the pan. Pull all the caps. If the crank is gouged the motor would need to be pulled. If there's metal dust the motor needs to be pulled and flushed. Probably need new oil pump but take it apart to look. Conceivably that debris could be timing gear stuff and/or the cam spun. Start looking for good used engine with TUPY head. You can still get the job done for about $600 if you go that route.

There's a glimmer of hope in that apparently there was no knocking, so maybe the crank is still good, but at 200,000 miles have a REAL low threshold to bail out.

third coast

Uriah, good job with what you have done and documenting your findings. Unfortunately the findings are as I expected but not what we hoped for. With that much antifreeze in the oil and visible metal in what was drained it is certain that wear surfaces have taken a beating.

One issue with antifreeze mixed in oil is that it forms hard precipitants, or particles, that can plug oil filters and lubrication paths and act as an abrasive in tight bearing clearances. When all is well the clearance between moving surfaces is very small with the load being supported by a thin film of oil. The idea is that normally there is not metal to metal contact. Once lubrication is compromised or contaminates are introduced bearing surfaces begin to gall, breakdown and displace metal. The displaced metal is what you see in the drain pan. The damage tends to avalanche until it is catastrophic. The larger particles are evidence of this. I have some experience in aerospace applications that have very challenging lubrication conditions and have investigated a number of failures. Once aggressive wear as we see here begins it is not a situation that will stabilize or is sustainable.

Even if what you can easily see by pulling the pan doesn’t look terrible there is a lot that you can’t see. Wear interferes with intended bearing clearances and disrupts oil film protection. Then there is the problem of cleaning the millions of wear debris particles and antifreeze/oil precipitants from this engine. Wear particles are in every nook and cranny and imbedded between every moving part. Just an oil change or flush isn't enough. Unless contaminates are thoroughly removed they will continue to cause damage. In my view, to expect significant and trustworthy life from this engine every critical moving part would be removed, inspected, measured and if to be reused thoroughly cleaned. Many wear couples would likely need to be refreshed and that is probably unreasonable from a cost standpoint.

Is it worth pulling the oil pan and bearing caps? Absolutely! Cut up the oil filter? I can’t wait to see whats there. Please proceed. You will learn a lot, any mistakes really don’t matter and with your reporting skills others will learn from this. The good news is that your Jeep got you home safely and you are learning a lot from this situation. I look forward to additional posts and pictures.

Dave51

Did you get a torque wrench and plastigauge yet? Check the torque when you break all the bolts. Also all the caps and bolts have to go back exactly the same way so mark them. Plastigauge is cheap but we can wait to see if there's any hope for this thing.