Pictures of a Sludged 2009 Murano with 15k

[SLCraig]

Originally Posted By: NewC6
I have an 05 Murano with the VQ35 and 51,000 miles, 6500 mile oil changes, always with PP. No oil usage between changes and when you look in the oil fill hole, the metal you can see has no varnish, no sludge. This is a pretty good engine as far as I am concerned.


They are great engines! they just need to be taken care of.

 

[The Critic]

Originally Posted By: demarpaint
Does this engine make the Amsoil sludge list, and shorter OCI recommendations yet?

All kidding aside, even though this engine was clearly neglected, this to me is not an engine I'd try an extended drain on.

This is merely an example of neglect. If the proper oil is used, it's certainly possible that an extended drain is do-able. Not to say that I would do it, but there's no reason to use this incident as an example of why extended drains are not possible.

 

[sprintman]

This is about the std oci for Australian cars and they all use dino and run for hundreds of thousands of km's. This is NOT 'extended oci' at all.

 

[demarpaint]

Originally Posted By: The Critic
Originally Posted By: demarpaint
Does this engine make the Amsoil sludge list, and shorter OCI recommendations yet?

All kidding aside, even though this engine was clearly neglected, this to me is not an engine I'd try an extended drain on.

This is merely an example of neglect. If the proper oil is used, it's certainly possible that an extended drain is do-able. Not to say that I would do it, but there's no reason to use this incident as an example of why extended drains are not possible.


I didn't say extended drains are not possible, they certainly are and are done by many members here. I said the engine in this Murano is not an engine "I" would try an extended drain on. It might just end up and the sludger list in the very near future. To me the risk/reward isn't worth it. I'd follow the OM servere service interval on this one. JMO

 

[rslifkin]

IMO, extended drains on this engine would definitely need UOAs to back them up, at least the first couple times. It's tough on oil, so if you accidentally push it a little too far, you can end up with a big mess.

 

[Craig in Canada]

I have a buddy with a Nissan Quest (also VQ35) who after talking to me went from OCI every 3,000km (yes, km, so 2,000mi) on M1 5W30 to Amsoil SSO and extended drains using UOAs to determine when to drain.

I think he exceeded 20,000km with little consumption. Again, backed by UOA to verify cleanliness, TBN etc...

 

[Corvette Owner]

As I said before, I have a 2006 Murano with 78,000 miles. I changed out factory fill at 3,000 miles and went with synthetic (M1 5W-30) with 7500 mile OCIs. No problems.

Recently I switched to PP.

 

[demarpaint]

Originally Posted By: rslifkin
IMO, extended drains on this engine would definitely need UOAs to back them up, at least the first couple times. It's tough on oil, so if you accidentally push it a little too far, you can end up with a big mess.


That's what I would do if I was going to do extended drains. The only downside with a known or potential sludger, is a UOA is not going to tell you if sludge and varnish is forming. I think in the case here the oil level was not checked and it was driven low on oil, compounding matters.

 

[rslifkin]

True. However, if the UOA still shows viscosity as being correct, and a reasonable amount of TBN remaining, that would give some indication that the oil isn't breaking down and sludging yet.

 

[Craig in Canada]

Originally Posted By: rslifkin
True. However, if the UOA still shows viscosity as being correct, and a reasonable amount of TBN remaining, that would give some indication that the oil isn't breaking down and sludging yet.


In my friend's case, I had him send the oil in indicating specifically that he was interested in extended drains and that this was not an OC, just a sample to confirm how long he could run. He did a number of samples on his way to his final mileage, watching the TBN fall a little and the lab's suggestions on when to change.

I know we debate the usefulness of UOAs for detecting "normal" wear, but if the claim is that UOA isn't going to see whether the oil is still protecting or not I have to disagree. The TAN/TBN tests, visc tests, dilution tests and adpack PPM measurements are exclusively testing the condition of the lubricant and if it's still fit for purpose.

If the assertion is that UOAs aren't good for detecting wear, nor are they good for determining if a lubricant is still fit, why do they exist at all?

 

[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.

 

[Garak]

Originally Posted By: demarpaint
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.


I'm going to play devil's advocate here. I'm very finicky about having a clean engine. I also know the limitations of UOAs, and we've all seen some pretty strange numbers in the reports we've seen.

However, in the grand scheme of things, if the engine is running well and quiet, does it matter if it's a bit varnished or sludgy inside? My first instinct is that the sludge must come out and the engine must be returned to a pristine condition. But, logically speaking, if it's running fine, does it really matter?

When I desludged my F-150 with a bunch of short OCIs on HDEO, I did it for purely aesthetic reasons. The engines was needing a rebuild, because the PO never changed oil. I simply didn't want the rebuilder to have to deal with a bunch of sludge, so planned ahead. It didn't run any better or worse before or after the sludge was removed. The only real concern that the sludge caused was the clogging of oil galleries.

 

[Spyder7]

Originally Posted By: Garak
Originally Posted By: demarpaint
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.


I'm going to play devil's advocate here.

...

However, in the grand scheme of things, if the engine is running well and quiet, does it matter if it's a bit varnished or sludgy inside?

...

It didn't run any better or worse before or after the sludge was removed. The only real concern that the sludge caused was the clogging of oil galleries.


Haven't you answered your own question - or is the possibly of a clogged oil passage and the (potentially expensive) damage it could lead to, reason enough. It was the only reason I needed. Anything else is a bonus, and delivered or not, immaterial to the reason I use it.

-Spyder

 

[Garak]

Originally Posted By: Spyder7
Haven't you answered your own question - or is the possibly of a clogged oil passage and the (potentially expensive) damage it could lead to, reason enough. It was the only reason I needed. Anything else is a bonus, and delivered or not, immaterial to the reason I use it.


He he, you caught me on that one. I'd merely suggest that most engines with some sludging (not the ridiculously sludged ones, either) wouldn't have catastrophically plugged galleries, like my 300 did. It wasn't marginally sludged because of extended OCIs on old style conventionals, either. It was ridiculously sludged, since the only time the previous owner changed oil was at rebuild time, and he bought the thing new. He topped up as needed, and that was it. He did a backyard rebuild and didn't clean the oil galleries, so his "rebuild," as it were, didn't last long.

The low oil pressure in my 300 was a dead giveaway. Not all sludged engines suffer reduced oil pressure. Of course, that depends on the amount of sludge. A minor mess is an eyesore. The mess I had was altogether different.

That being said, it ran for about eight years with low oil pressure, and drove just fine to the place where I had it rebuilt. Many changes of HDEO and Valvoline MaxLife 5w-30 cleaned it out nicely; the galleries obviously still required a manual cleaning.

 

[demarpaint]

My point is this, an engine can run fine with some sludge, but if you someone thinks a UOA is going to tell them how clean their engine is they are wrong. Also extended drains are not going to help aid in keeping an engine clean, as you already stated, from your experience. That's all I'm saying.

Like clogged arteries, eventually sludge will do damage, how much and when is the question. Unlike blood work to detect cholesterol in an attempt to avoid the damage in people, a UOA is not going to detect damaging sludge in an engine. Fuel dilution and coolant perhaps, then will still have issues with the accuracy of the reports. JMO

 

[Craig in Canada]

Originally Posted By: demarpaint


Like clogged arteries, eventually sludge will do damage, how much and when is the question. Unlike blood work to detect cholesterol in an attempt to avoid the damage in people, a UOA is not going to detect damaging sludge in an engine. Fuel dilution and coolant perhaps, then will still have issues with the accuracy of the reports. JMO


But sludge only forms when the oil has deteriorated past a certain point. Varnish can be a function of high heat and a number of other things, but sludge is not. A UOA should easily be able to detect conditions conducive to sludge formation (high moisture, high fuel, low TBN, high TAN etc...)

 

[Spyder7]

Originally Posted By: Craig in Canada
Originally Posted By: demarpaint


Like clogged arteries, eventually sludge will do damage, how much and when is the question. Unlike blood work to detect cholesterol in an attempt to avoid the damage in people, a UOA is not going to detect damaging sludge in an engine. Fuel dilution and coolant perhaps, then will still have issues with the accuracy of the reports. JMO


But sludge only forms when the oil has deteriorated past a certain point. Varnish can be a function of high heat and a number of other things, but sludge is not. A UOA should easily be able to detect conditions conducive to sludge formation (high moisture, high fuel, low TBN, high TAN etc...)



I'd probably have to dig really deep to (hopefully) find it, but (even though it wasn't the focus of the white paper) there was a very well written description of different factors that could create sludge (the person writing it, because of his background, was someone I accepted as an expert).

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 wish I copy & pasted and saved the write up.

Edit: I think there is an important difference between varnish and sludge; varnish will occur naturally over time, and is not only normal, but not even harmful. Given that it may provide an additional friction barrier between metal, it *may* even be beneficial.

Varnish is only bad (imho) when its allowed to go beyond varnish, and sludge develops. Sludge is never a good thing. Varnish I would not only not be concerned with, but I would be more concerned about taking drastic measures just to remove it (solvents, abrasive detergents, etc).

-Spyder

-Spyder

 

[KieferS]

Just another reason I stick to 3300 mile OCI. Even with my royal purple.

 

[Billy_D]

Originally Posted By: KieferS
Just another reason I stick to 3300 mile OCI. Even with my royal purple.


My wife before we met was doing 7500 miles with Amsoil XL sold at the dealership. She never had an engine problem. You can change your oil every 3k miles if that's what you want to do. But Royal purple can handle at least 5000 miles under non severe conditions.

 

[JOD]

I still don't get why people keep referring to the VQ as a 'sludger'. Is there a single instance of this engine sludging when it's actually kept full of oil?

There's no reason you can't run a reasonable OCI if you actually keep oil in the sump.

Check out these two UOA's linked on this page. And check out the make-up oil used on each engine. Yikes!