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In the last issue I said that mechanics should be called "automotive systems analysts," because the knowledge and experience we must acquire to be good truly earns us that title. I also said the engine's oiling system was an all-important system. In this issue, I would like to take the oiling system discussion a bit further and talk about a topic automotive analysts everywhere will be able to relate to: sludge.

Horror stories have been passed around for years about this motor oil or that motor oil causing sludge. The fact of the matter is that no motor oil causes sludge. In fact, motor oil actually helps prevent sludge.

Then where does sludge come from? In our continuing quest for oiling systems knowledge, I thought it would be good to take a minute and further investigate what sludge is, how it forms, and how to prevent it. I also want to explain how a top-quality motor oil, like Pennzoil, keeps engines free of sludge, deposits and corrosion.


The Sludge Monster

We've all probably taken apart an engine or seen an engine that's been consumed by the "sludge monster." It's not a pretty sight and has been the cause of death of many engines. The first clue that an engine has been inhabited by the sludge monster usually becomes evident during an oil change (when the thick goo dribbles out the oil pan drain hole or nothing at all comes out). We usually identify the fatal cases of sludge monster victims after the vehicle arrives at the shop under the auxiliary power of a wrecker.

Contaminants and Sludge

Contaminants are deadly enemies of an engine. They enter with the air flow and are also generated by the friction of metal against metal. These facts may astound you: for every 100 gallons of gasoline burned in an engine, the following by-products are produced:

90 to 120 gallons of water

3 to 10 gallons of unburned gasoline

1/2 to 3 pounds of soot and carbon

1/4 to 1 pound of varnish

1 to 4 pounds of sulfuric and nitric acid

A measurable percentage of these by-products ends up in the motor oil. Detergents and dispersants in the oil must be able to keep most of these con-taminants neutralized or suspended in the oil as microscopic particles so they don't form sludge, damaging deposits and corrosion. When the waste materials are dispersed properly in the oil, the filter can trap the larger particles. During an oil change, the contaminants too small to be filtered are re-moved with the engine oil. Looks good on paper, right? So much for the perfect world. It's important to note here that good air filters and good oil filters trap more contaminants than lesser quality filters, making the oil's job easier.


Paraffin-based Crude Oils

Most people relate the word paraffin to candle wax. This is a correct association, BUT one of the most incorrect and widely circulated misconceptions about sludge is that it forms more easily in paraffin-based motor oils. This couldn't be further from the truth. All major motor oils, in fact, are formulated using a paraffin-based crude oil. Naphthenic-based crude oils are actually more likely to form sludge in an engine than oils formulated with paraffin-based crude oils. This is due to the higher breakdown resistance of paraffin-based crude oils. O.K., so how does sludge really form?

How Sludge Forms

Sludge formation begins when the chemically suspended particles of contaminants begin to settle out of the oil. It's a fairly daunting task for engine oil to suspend all the contaminants thrown at it, and any engine oil can do this successfully to a point. Pennzoil, and some other quality motor oils, are able to perform this task more effectively and for longer periods of time. But eventually, if the oil is not changed often enough, a "breaking point" will be reached. This breaking point is either when there are too many contaminants to handle or when the oil's chemical defenses are weakened, and it is caused by two main things: excessive accumulation of contaminants in the oil and chemical changes in the makeup of the oil itself (depletion of the additives and oxidation).

As more particles are suspended, less of the additives are available to do their job. Knowing this makes it easy to see why too much time between oil changes can be one cause of the oil reaching its "breaking point".


A Surprise Visit From the Sludge Monster

Another cause may surprise you: running the engine low on oil for a prolonged period of time can cause sludge. The detergent and oxidation inhibitors are important components of the additive package that prevent sludge from forming. When an engine is run low on oil, these additives have to work overtime to do their job. There is simply less of the additive package available to do the work of suspending particles and preventing oxidation (thickening) of the oil.

Here is the surprise part: running an engine just one quart low on oil for about as long as some technicians work in one week (about 55 hours) can increase the viscosity, or the thickness, of the oil by over 1000%!!! I don't know many technicians, or car owners for that matter, who would like to run 5,000-30,000W oil in their car's engine. If you factor the effects of the increasing use of self-service gas stations into the equation, you can see how the sludge monster can unintentionally be invited to pay a visit to so many engines.


Eliminate Surprises

The sludge monster's invitation can be repeatedly rejected. To keep the sludge monster looking for a dinner date in someone else's engine, use a quality oil like Pennzoil, with its super powerful Z-7ยจ additive package and change it at recommended intervals. It's like making sure the Kryptonite never gets near Superman.

 

Great post man. People don't ever realize how something as simple as checking your fluids can keep your car running longer. That's why its always worth the extra $5-20 to get the full service on an oil change.

 

I'm glad I read that. I've always got my oil changes down it the dealership. I was thinking about going to start going else where but now I won't. The dealership I work at only charges $19.95 for me and our customers.
thanks for the post

 

I COMPLETELY AGREE ON FACTORS OF THE SLUDGE MONSTER!! NEARLY ALL PETROLEUM BASE LUBRICANTS ARE THE SAME, THE ADDITIVE PACKAGES WILL CHANGE THEM SOMEWHAT BUT NOT MUCH. SYNTHETIC BASE OILS ARE FORMED FROM ESTERS AND DI-ESTERS (WHICH ARE CHEMICALLY FORMED FROM TWO THINGS THAT WE WOULD NOT WANT IN OUR CRANKCASE, AN ALCOHOL AND AN ACID) BUT WHEN THEY ARE COMBINED MOLECULARLY THEY FORM A FINE BASE FOR SYNTHETIC OIL THAT HAS THE BUILT IN RESISTANCE OF CONVERTING BACK TO EITHER ACID OR AN ALCOHOL.
A GOOD FRAM OR HASTINGS OIL FILTER WILL FILTER OIL BETWEEN 20 AND 25 MICRON AND AMS/OIL HAS A FILTERS THAT FILTER BETWEEN 3 AND 4 MICRON, THEY ALSO HAVE A BY-PASS FILTER SYSTEM THAT TAKES THE SURPLUS OIL ON THE RETURN PATH AND PUT IT THROUGH THIS LARGE 1 MICRON SPIN-ON FILTER, WHICH ACTS LIKE A NEW OIL CHANGE EVERY 25 OR 30 MINUTES THAT IT TAKES FOR ALL OF YOUR OIL TO HAVE PASSED THROUGH THE SYSTEM, AND IT ALSO ADDS ANOTHER QUART TO YOUR OIL LUBRICATION SYSTEM, WHICH CARS AND TRUCKS HAVE SMALLER SUMPS AND HIGHER RPM AND MORE HEAT, THEY CAN USE THE EXTRA CAPACITY. A SIDE AFFECT WITH SYNTHETIC OIL IS THAT YOUR CRANKCASE TEMPERATURE WILL MORE THAN LIKELY DROP 20 TO 25 DEGREES, F., WHICH IS WHERE THE CRITICAL TEMPERATURES ARE FOR ENGINE OIL LIFE. THE TEMPERATURE DROP BECAUSE OF LESS FRICTION ON THE CRANK AND VALVE TRAIN, AND LESS FRICTION MEANS MORE POWER. I INCREASED MY FUEL ECONOMY BY 15% RUNNING AMS/OIL 5W30 TURBO 100% SYNTHETIC AND TWO AMS/OIL FILTERS, BY-PASS AND FULL FLOW.

I HAVE AN 80 GMC DIESEL WITH A 5.7 LT ENGINE IN IT, &. EVERY MISTAKE THAT A DESIGN ENGINEER CAN MAKE IS RIGHT THERE, ANYWAY I HAD AMS/OIL 15W40 DIESEL OIL IN IT A FEW YEARS AGO WHEN THE CONNECTING ROD LET GO AND WHEN I TORE IT DOWN YOU COULD EAT OF THE INSIDE OF THE ENGINE IT WAS SO CLEAN, ABSOLUTELY NO SLUDGE. IT HAD AN ASF-15 SPIN ON FILTER AND A BY-PASS FILTER SYSTEM AND A LIFE TIME LT-52 AIR FILTER. FROM GRAHAM

 

Ok, then I have this one question. What is best for a 5w-20 v6 2.7l engine like my 2005 stratus?

I see you post about penzoil, but I have seen a mechanic open up a valve cover, and it had sludge all over the top of it, and that's all they used was penzoil. I have always been skeptical about their product, so have always used three kinds, halvoline and valvoline.

what is your input on that please, I'd gladly like to know, before I get into this maintanence routine.

there were filters from fram up at wally land, like the 7000 mi filter, is that a good selection when shopping, it was the xx16 series. Talked good about the anti-drainback valve on this particular filter.

and synthetic v. blend v. standard, does it matter this early in the stage? what about by-pass and full flow, how you do that with one filter? ugh, sorry, i'm lost, thanks in advance, look forward to replies.

Thanks!

 

There are two separate issues, often confused with one another. The first is traditional sludge, exacerbated by short trips, and eliminated by frequent oil changes. The second is coke, caused by high engine temperatures (turbocharged engines, certain Chrysler V6s), for which the solution is frequent oil changes with SYNTHETIC oil.

 

The Sludge Monster is only able to survive in spaces equating to 2.7 litres of cubic capacity, and prefers to sleep on an alternating basis in one of 6 cylindrical caves. It's preferred diet are members of the sub-species Moronicus Moronicus, who are found exclusively in the showrooms of Dodge dealerships. The Sludge Monster is known to emit noxious blue smoke when threatened and is known to be particularly afraid of Mobil 1, the toxicology of which is particularly damaging to the Sludge Monster's biological makeup. The only known cure for the bite of this creature is the rapid infusion of 9,000 dollars either in soluble cash or check form, even then, a repeat attack remains likely.

 

great post THUMB. keep in mind everyone, the biggest by-product of combustion is water. as water evaps at a low temp, it leaves all the stuff it was holding (think of hard water drying on the paint, you end up with waterspots) in the oil/eng. it norm takes almost 1 hour of driving to heat the oil enough to boil off the water (witch holds the "junk" that can mess up the eng) out of the oil. the HARDEST thing your eng does is city driving. this is why the maint book says to change the oil at 3K's for "HARD" driving (5-7K's for i-state driving). while modern eng oils can last for 7K's+, the stop and go/short trips of city driving fill up the add packs like THUMB stated. even if you use full synth, this can still happen. if you drive in city, just use reg oil and change every 3K's. happy mototing.

 

Anyone tried this product?


http://www.auto-rx.com/pages/applications2.htm

 

well besides penzoil what are some premium oils out there without going synthetic. this is where some opinionated answers come in but id like to know, quaker state, mobil 1, valvoline, what!?!