The lower viscosity oils were introduced for EPA fuel mileage gains mostly.

 

Yes, oil from the top end drains through the valley back into the oil pan. Which mean that the crankcase, valley, and valve covers share internal atmosphere. That's why the PCV, located on top of a valve cover, is used to extract crankcase gases.

Actually, I'm following along. I responded to a question by user Ram05red and you quoted my response and posted an infantile gif. That makes you the bully who started the personal attacks. Duh.

Yeah, it's real funny that each time I point out where you're wrong (that_guy: there is no sludge problem with these motors), you keep coming back with gif attacks and inane, unrelated comments. Hilarious!

 

So now you're saying the valley and the valve covers are the same. Yet again you're just making up whatever supports your argument.

And you came back to a thread where you were wrong 4 years ago just to spread more misinformation, and you started the personal attacks (you must be insecure about something).

You are wrong, there is not a sludge problem.

 

It has a significant bearing on the maintenance interval in that the defect requires a shortened interval in order to reduce sludge build-up. Engines that could operate normally with 5K or 7.5K oil changes require changes at 3K or less until the plenum leak is fixed and its aftereffects cleaned up.

Nothing I wrote is contradictory to how engines actually operate. I provided links to supporting material and quoted from Chrysler and other documentation. If there's something I wrote that's unclear, please quote it and I'll clarify if needed.

 

Well after changing the oil sending switch and draining the oil and running a flush through it it seems to be working okay now
Now it's on to the timing chain change.

 

I second that.

The 4.7L doesn't have the plenum pan gasket problem that the 1992-2003 3.9L/5.2L/5.9L Magnum engines did. The gasket leak could contribute to sludge problems even if the oil and filter were changed on the severe service interval and indubitably did so when oil and filter were changed on the normal service interval or longer.

 

Glad to hear it's taken care of now, and it was just a switch.

You second it, and then continue spreading false information right below here. You must have problems.

Even with the plenum leak, they do not have a sludge problem.

 

No it does not. An oil leak or consumption of oil has NOTHING to do with a maintenance interval. "Maintenance" does not, nor will it ever, compensate for a defect. Just for the sake of the argument, I'm throwing out numbers here. Say the book calls for a 5,000 mile oil change across the board. When these plenums leak, the vacuum in the intake manifold sucks oil in, which then gets burned in the combustion chamber. Yes, there are missing steps in there, I'm not gonna nitpick it to death. But that's what happens. No sludge buildup occurs. You could run low on oil if it's a bad enough leak. But again, maintenance intervals are not designed around a possible defect. This would be no different than having an external oil leak. If your vehicle develops an oil leak, you can blame Chrysler all day long, but It doesn't change the fact that you should now check your oil level routinely to make sure it doesn't ever get to a critical level.

But I guess one could always make the argument that their oil change intervals should be reduced to say, 3000 because their specific engine developed a problem and they want someone else to take the blame. If that's the case, Chrysler owes me a new engine, transmission, and a rear diff. And a rebuild on a transfer case. Hey you know what, that doesn't sound half bad. Maybe you're actually on to something here.

 

Lets for a second assume that he is right(hypothetical thought expiriment time), a leaking plenum does cause sludge because of all the reasons that he mentioned (we all know it doesnt, and my future wife a tribologist and i will have another good laugh about this guy over dinner). Now it will take a fair amount of TIME for this so called sludge to form, alot more than one oil change interval, in that time the oil consumption should be noticed (at the very least) and most likely the rough running (from fouled plugs caused by burning oil) and the problem (which is extremely easy to find, especially since its a well known issue) should be found and repaired. So even if it was a cause of sludge its not something that would be left long enough (see the proper maintance and repair claim) to cause an issue.

At this point its obvious that we are not going to get through to this guy, we have 2 engineers and several experienced well informed individuals in this thread and hes not seeing it.

id also like to emphasize this point, even modern conventional oil has such strong detergent and additives in it to maintain viscosity that you would have trouble sludging an engine, hell mobile one claims there oil is good for 20k miles (i cant pesonally recommend that long of a change but its impressive none the less), i run 10k mile intervals (full synthetic of course) on both of my hemis and my fiances hyundai 2.0t with clean oil analysis reports on all fronts.

 

Why do some Mopar engines have a sludge problem? Dr. M David Checkel, who received his PhD from Cambridge University and is Professor Emeritus of Mechanical Engineering at the University of Alberta informs us that:

[QUOTE][Spark] Knock intensity can vary depending on how much end gas auto-ignites. The classic signal of knock is a rattling, pinging noise in the engine. However, this noise may not be detectable by the driver, particularly for moderate knock occurring when vehicle noise is high. Beyond the undesirable noise, knock has several other effects including increased cylinder pressure and temperature, increased NOx (oxides of nitrogen) formation, increased cylinder leakage (blowby) and increased cylinder heat losses.

With lower knock intensity, engines may still have sufficient cooling capacity to control component temperatures and avoid direct thermal damage. However, in this situation, the engine is subject to increased thermal stress and increased chemical stress due to sharply increased NOx production. The increased combustion chamber leakage associated with knock delivers high-NOx blowby gases into the crankcase and valve cover areas. The NOx acidifies the oil and, aided by the high oil temperatures associated with knock, reacts with fuel components from the blowby to create solid compounds. These compounds form solid surface deposits and oil-borne sludge, both of which interfere with the lubrication system's capabilities./QUOTE]

In addition, a case study in the Industrial Lubrication and Tribology journal reported that:

Furthermore, according to section 32.7.3.4 of the Modern Tribology Handbook:

By the way, what is sludge? According to ALS Tribology, an oil analysis and testing company:

How do we know about the Mopar sludge problem? Because Chrysler Corporation's Technical Service Bulletin (TSB) regarding the plenum pan gasket leak contains two relevant statements that support the conclusion there are solid compounds created because of the leak.

1. Symptom: An engine intake manifold plenum pan gasket oil leak may occur on some V-6 and V-8 style engines. Two symptoms of this oil leak condition may be present. The vehicle operator may experience an engine spark knock during acceleration and/or an increase in the amount of engine oil consumed by the engine.

2. Repair: [step 4 and notes] Allow the combustion chamber cleaner to soak inside of the engine for 2 to 2.5 hours. A second application of the combustion chamber conditioner may be required if there was a large quantity of oil leakage past the intake plenum pan gasket.

What does that mean? First, a major contributor to sludge formation is spark knock, and the TSB informs us that one of the major symptoms of the plenum pan gasket leak is spark knock. Second, the TSB alerts us to the fact that the leak causes carbon build-up (solid surface deposits) on the pistons and rings, thereby increasing the amount of blowby gases being funneled to the crankcase and oil.

Can I have surface deposits and oil-borne sludge buildup even if I change my oil frequently? Yes, as the article Under the hood: Investigating oil sludge accumulation claims by insurance underwriting investigator Dr. Charles C. Roberts, Jr. demonstrates, even owners with verified documentation of regular maintenance are affected. Engine blow-by gases, vaporized oil and air from the breather system are drawn into the intake manifold through the pan gasket leak, contaminating the engine oil that is recirculated to the oil sump. The investigation concluded that the engine problem was not a result of poor maintenance, but an engine component failure: premature failure of the plenum pan gasket. The dealer repaired the engine at no cost to the insured or the insurer.

Who is this comment addressed to? Please note that this write-up specifically addresses oil sludge problems attributable to plenum pan gasket leaks. That particular problem is limited to 1992-2003 3.9L/5.2L/5.9L Magnum engines. However, other things, such as failing to change the oil and filter often enough or a defective PCV can also lead to sludge build-up in those and other engines. The symptoms of oil starvation (discussed next) are the same regardless of the cause of the sludge.

What are the symptoms of sludge build-up? During vehicle operation, the oil pressure gauge may swing wildly and eventually drop to zero as the engine warms up. When the engine is stopped and allowed to cool for a period of time, oil pressure may return to normal until the cycle repeats the next time the vehicle is driven.

If you continue driving the vehicle after pressure drops to 0, classic symptoms of oil starvation will appear. The lifters will start clattering and the engine may develop bearing knock and spark knock. It may start smoking. These symptoms are bad and you need to immediately shut down the engine, as continued operation will result in a severely damaged engine.

What else causes similar symptoms? Low oil level, of course. A bad camshaft or crankshaft bearing. A defective oil pump. You can rule out a faulty oil pressure sending unit, however, because a bad sending unit only affects reported pressure and doesn't impact other mechanical systems.

Is there an impact on oil consumption and oil level? Yes, the engine is burning oil, so it can consume up to two quarts of oil every 500 miles in severe cases. The leaky plenum gasket can also make it difficult to accurately read the oil level. As the engine runs, oil is pulled into the plenum section of the intake manifold. After the engine is stopped, it takes a while for this oil to drain back to the oil pan. Until it does, the dipstick reading will be incorrect. This may lead to overfilling, which can cause the oil pump to cavitate.

How do I fix my vehicle? There are a couple of great writeups here on Dodge Forum about the plenum gasket repair, and Chrysler's TSB gives one method of doing so. However, the best fix is replacing the factory plenum pan, which is steel, with an aftermarket aluminum version. Make sure to remove any carbon buildup inside the intake manifold or on the lifter valley. Also, decarbonize the cylinders using the procedure in TSB 09-05-00.

As for de-sludging the engine, a mild case may be resolvable with an oil treatment or with sequential oil changes using high-detergent oil. More severe cases require pulling the valve covers and removing any sludge, and also dropping the oil pan to remove any sludge in the pan or on the engine's bottom end components. In addition, you'll need to remove any sludge or carbon buildup on the oil pickup screen. After cleaning under the valve covers and oil pan, a further oil treatment may be required to flush out any sludge remaining in the engine's internal oil passages, in or around the oil pump, or in the lifters and pushrods.

References
----------
1. Industrial Lubrication and Tribology, Volume 42 (1): 7 – Jan 1, 1990. Investigation of Sludge Formation in Gasoline Engines by J.R.F. Lilywhite et. al.
2. Modern Tribology Handbook, Two Volume Set, Section 32.7.3.4. Effects of Service on Engine Oil Properties
3. ALS Tribology website. The Formation of Deposits in Lubricating Oil Systems by Michael Holloway, CLS
4. Chrysler TSB 09-05-00
5. AMSOIL TSB MO-2005-09-30
6. Damage Associated with Uncontrolled Knock in Spark Ignition Engines by Dr. M. David Checkel
7. Under the hood: Investigating oil sludge accumulation claims by Dr. Charles C. Roberts, Jr.