Pictures of a Sludged 2009 Murano with 15k

[Craig in Canada]

Originally Posted By: Spyder7

Some of the factors were things I wouldn't have thought of; for instance, he stated that a poorly ventilated engine area can, if conditions are right, result in oil sheering, and hydrocarbon cracking that can form sludge. The description made me think of a car stuck in traffic in summer heat, where no air is being pushed into the engine bay beyond what the electric fans can pull in when they spool up.


I'm guessing, but you could have misinterpreted what you read based on what you wrote here. It's been discussed that improperly functioning crankcase ventilation (PCV/CCV system) will cause sludge buildup. A couple of paraphrases down the road and that could easily be misinterpreted by a casual reader as "engine ventilation" in the way you've described it.

The two are not the same. Hot engine compartments and oil simmering in poorly cooled, low circulation areas usually forms varnish and coking more than gooey sludge from everything I've read.

 

[kbohip72]

Originally Posted By: demarpaint
IMO a UOA is a rough guide, it is not the end all be all that some make it out to be. There have been stories here on Bitog of people getting UOA reports which were good, only to find upon an engine tear down that bearings were shot, or the engine wasn't as pristine as they thought it would be based on the UOA reports. It will tell TBN/TAN, wear metals. It is not going to determine how clean an engine is. I've seen first hand engines that ran well, and quiet, and upon visual inspection were a mess.

It is a tool, good for diagnosing, coolant leaks, fuel dilution and certain problems. UOA reports are far from fool proof, and many contain some major errors, as I've seen here on Bitog.

Then if someone's favorite oil shows more iron than another oil, it is something that is up to heated debate. In which case the defender of the favorite oil will have many reasons for why certain metals read high. I'm trying to keep an open mind, but IMO they have some limited value.


The only UOA I ever had was on am '03 Jeep Grand Cherokee with the HO V8. It was a total waste of $20 imo. The oil was M1 10W-30 and the oil was drained at only 2,500 miles and 3 months. The analysis came back with wording to the effect of "we don't recommend a longer oci on this vehicle." Really? 2,500 on synthetic is as good as you think it'll go? Lol, whatever.

I came to later find out that they weren't using the specs off of my HO V8 engine, but the specs of the regular V8. What annoyed me is I made a lot of notes that this was the HO V8 when I sent the sample to them. Apparently they just ignored this. I haven't had a uoa since and won't again. I'd rather just put the money towards a shorter oci and not worry about it.

 

[demarpaint]

I think along the same lines. I read UOA reports here, and realize that for $25-$30 how much time is really spent on them? Then the accuracy issues, along with major mistakes as well. I wouldn't be confident in the results either. I'd rather shorten the OCI, and do as I've done since the 1970's until I feel more confident in them. I've never lost an engine nor have I paid for a UOA. Opinions vary, mine might change if my confidence level in them increases. JMO

 

[kbohip72]

Originally Posted By: demarpaint
I think along the same lines. I read UOA reports here, and realize that for $25-$30 how much time is really spent on them? Then the accuracy issues, along with major mistakes as well. I wouldn't be confident in the results either. I'd rather shorten the OCI, and do as I've done since the 1970's until I feel more confident in them. I've never lost an engine nor have I paid for a UOA. Opinions vary, mine might change if my confidence level in them increases. JMO


Exactly. Now if regular oil hits $6 a quart and synthetic goes to $12 a quart for whatever reason? Yea, I'll be mailing old oil to Blackstone again.