Interesting Oil Sludge Article...

[ToolGuy]

The Steering Column 1 2 In this century, changing your oil still matters.BY CSABA CSEREDecember 2004 Over the decades, new technologies have reduced the needs of automotive maintenance. Grease jobs for chassis lubrication are a thing of the past. So are tuneups. Spark-plug changes are as long as 100,000 miles apart. And oil-change intervals have also been extended. When I started driving in 1967, oil was changed every 3000 miles. Now, 7500 miles is almost standard. Our last Porsche 911 long-term car only required an oil change every 15,000 miles.It's enough to make some drivers forget entirely about maintenance. But despite their onboard microprocessors, polished wood, tanned leather, and gleaming paint, cars are still machines full of parts that rotate and rub and survive only through lubrication.Recently, Volkswagen sent a letter to owners of 1998-through-2004 Passats equipped with the 1.8-liter four-cylinder turbocharged engine informing them that it was extending the warranty on the engine to cover problems caused by oil sludge. Owners of Audi A4 1.8Ts received the same letter. Chrysler 2.7-liter V-6 engines have had similar problems, as have some Toyota V-6 and four-cylinder engines. The number of engines affected is small in each case, but in this computer-controlled age, oil sludge sounds like a Neanderthal problem.Sludge is a thickening of the engine oil until it reaches a jelly-like consistency. When the crankcase of your engine starts to accumulate sludge, the thickened oil finds its way into the passages that carry pressurized oil to the engine's bearings and other lubricant-needy parts. Since many of these passages are about the size of a small soda straw and sludgy oil has the consistency of an icy milkshake, the oil flow can become restricted. If that happens, components such as valve lifters soon start wearing rapidly and operating erratically.There are several ways for sludge to form in your engine. Water gets into the crankcase through condensation and blowby from the combustion chambers. Water mixed with oil takes on the consistency of thick, pus-colored foam. You'll know it if you see it.Fortunately, small quantities of water evaporate from the crankcase as the engine warms up and the oil temperature gets above 212 degrees, which it does after a few minutes on a freeway. However, if you only drive short trips, your crankcase never gets hot enough to evaporate any accumulated water, and in such an engine, sludge formation seems certain in its future.Sludge can also form if the oil gets too hot. At temperatures above 250 degrees, nonsynthetic oil starts to oxidize. Such oxidation thickens the oil and produces acidic byproducts. The process accelerates when the oil temperature hits 300 degrees, and the result is something more akin to tar than oil.Even in 24-hour races, I've never seen an indicated oil temperature approach 300 degrees. But it's still possible for engine oil to experience near-300-degree temperatures somewhere in the engine. If that takes place, the oil will oxidize, a little bit at a time, which is why good engine design seeks to eliminate such hot spots. The final cause of sludge is simply the passage of time. Tiny particles of soot get by the piston rings and end up suspended in the oil. So do various acids formed by the products of combustion. Oil contains additives designed to neutralize these contaminants, but eventually, enough of this foul stuff builds up to compromise oil's lubricating qualities. Manufacturers conduct tests to determine this contamination and specify oil-change intervals accordingly. And therein seems to lie the cause of the sludge problems.According to Toyota, many of the company's sludge-damaged engines were in cars with 30,000 to 40,000 miles that had recently come off lease. Some of the engines still carried the original oil filter that was screwed on when the car left the Toyota assembly line, leading Toyota to conclude that some lessees were remiss about changing their oil.Other diligent owners changed their oil, but as it turned out, not often enough. Like most owner manuals, Toyota's specified oil changes at 7500 miles. But its manuals also specified 3750-mile changes for cars in "severe" service. "Severe" service applies to vehicles used on short trips, especially in winter, situations where the engine never warms up. It also involves towing and stop-and-go driving in heavy traffic, especially in hot climates, which elevates oil temperature. These are exactly the conditions that promote sludge formation.So how is an owner to determine the threshold between "normal" and "severe" service? Toyota concluded that an owner couldn't be expected to know and has since revised its oil-change schedules for all its vehicles to 5000 miles.That's the same interval VW specifies for the 1.8T engines in the latest sludge case. Although these engines are also used in Audi TTs and VW Jettas and Golfs, the sludge problem seems confined to the VW Passat and Audi A4, which are heavier than the other cars and whose engines are mounted longitudinally rather than transversely.In these 1.8T applications, the oil seems to run hotter and won't last much beyond the 5000-mile change interval. As a result, for these engines Volkswagen now recommends one of several synthetic oils that meet a specific VW 502.00 standard. Furthermore, VW's extended sludge warranty only applies to owners who can demonstrate that they changed their oil according to the factory schedule.The best solution to the sludge problem seems to be the oil sensors that have been used for years on all BMWs, along with more than 90 percent of GM vehicles. These devices are not really "sensors" that somehow analyze oil quality; they are software programs that record cold starts, oil temperature, and a count of cylinder firings. The systems then infer the oil's condition based on its measured "experience." They can call for oil changes in fewer than 5000 miles and more than 10,000 miles, depending on driving conditions.Until oil "sensors" become universal, you are well advised to change your oil according to factory recommendations and adopt the "severe" interval if you have any doubts about your driving conditions.And check your oil regularly. It's not only important to keep the crankcase full, but your dipstick can reveal the moisture-induced dirty foam or the heat-formed tar that indicates a sludge problem, and a potentially expensive repair, in your engine's future. BTW, taken from Car and Driver, Dec 2004.

[MadBill]

Good article! The straight story, with no spin-doctoring or axe to grind.

[Roadpig]

I have about 6K on my current oil, guess I'd better change it.

[ragingfish]

I run 5000 mile change intervals on Mobil 1...no problems yet! Thinking of doing an oil analaysis on my next change, just for kicks...

[soldierguy]

I've always been overly cautious when it comes to oil change intervals. If I do a cross-country trip I'll let it slide to 5000 miles, but other than that, I do it every 3000.But I never really believed the claims about superior lubrication with synthetic oils until a few years ago.My old 96 Jetta GLX had an oil temp readout in the on-board computer. On regular oil it routinely ran 212 degrees around town (speeds up to about 40 mph), and about 228-230 on the highway. I never thought much of it. Then on one trip I found myself in an interesting situation: heading east on I-10 out of LA there's this hill that is several miles long. Going up this hill I was cruising at about 75 mph, the outside temp guage was reading 117 degrees, and for the first time since I had owned the car, the coolant temp gauge was reading above the middle mark. I clicked over to the oil temp display and saw 252 degrees!!! It scared me, so I decided to try synthetic oil. By the way, the coolant level was fine and the mix was right.About a month after the switch to synthetic, I found myself in the exact same situation...same location, same outside temp, same speed, except the water temp gauge was reading normal. I clicked over to the oil temp display: 232 degrees.I also noticed that my usual city driving temp had dropped to 196 degrees, and the usual highway temp had dropped to 212-220 after the switch to synthetic.Now I'm no scientist, but I do know that a byproduct of fricton is heat. In my mind, if just switching to synthetic dropped my oil temps as much as it did, then there must have been less friction. Less friction also means less wear on those moving parts. With engine tolerances as close as they are today, I'll never go back to regular oil...synthetic gives me a peace of mind that's worth the money.

[AKLGT]

well i don't know about all the scientific reasons or whatnot to switch to synthetic, but i can tell you i notice a difference in mileage and how the engine seems to run (except winter, it just runs rough regardless). my job requires me to have reliable transportation, i signed a contract stating such. so, i depend on my vibe gt to ensure i have a well paying job! it's getting full synthetic forever!

[cdFxer]

And I thought I was being a 'wild man' by running 4500 miles/oil change on my truck. The Vibester us gettin' it at 3k to 4k, regular. Only been over once when SHE was driving it....grrrrr.....

[futseal04]

Hmmm.....this post just reinforces what I have thought all along. I have always had a ritual every 5000 miles: synthetic oil change, tire rotation/brake inspection, and STP fuel treatment in the tank. I just hope that the Amsoil camp reads this article and thinks about it.....

[ToolGuy]

I always change the oil at 3,000 unless it is syn. With my one car that runs syn it has an digital oil life monitor and when I run it hard the % drops, like the gas gauge! The article reinforces the fact these gauges do not lie and without one, there is no way to tell the life, just going by the change interval is not good enough. Like Toyota changed theirs. Plus a GM Master Tech mechanic friend of mine said the gauge in my car is dead on and he specializes in certain vehicles with it. I do my changes myself so I save and can do it easily and have a place that recycles it for free. Changing normal oil at 3,000 keeps the engine quiet, keeps gas mileage up and I know the engine will last the long haul; cannot hurt to do it at 3,000 regardless. Even my leased cars get it at 3,000.

[ColonelPanic]

Great article! I've read a bit about the Toyota sludging issues in particular, quite alarming. Although thankfully, from what I've read it seems to affect Toyota's larger engines more than it does the 1ZZ. I have found a few sludging complaints on the 1ZZ, but they seem to be few and far between and most appear to be due to neglect by not changing the oil. Regardless, sludging has always been a concern with this car, so I try to keep fresh oil in the Vibe whenever possible. I did my first oil change at 1500 miles, another at 3,000, and every 3,000 ever since. Although most of the time, it gets changed a couple hundred miles before the 3K mark. Even if I was running syntethic, I still could't bring myself to push it too far on the same oil, regardless of the manufacturer's claims. Even if it supposedly lasted 30,000+ miles, no way could I keep that stuff in the engine for such a long time. I'm pretty (removed) about over-maintaining my vehicles. It looks like Toyota does have an oil life monitor in the 2005 Matrix. I was reading a copy of the owner's manual I downloaded, and found a "MAINT REQ'D" indicator mentioned :Quote »(n) Engine Oil Replacement Reminder Light (for vehicles sold in U.S.A.) This light reminds you when to replace the engine oil. This light will come on when the ignition key is turned to ON and will go off after about a few seconds. When you drive for about 7200 km (4500 miles) after the engine oil replacement, this light illuminates for about 3 seconds and then flashes for about 12 seconds with the ignition key turned to the ON position. If you continue driving without replacing the engine oil, and if the distance driven exceeds 8000 km (5000 miles), the light will come on after the ignition key is turned to ON position. The light will remain on thereafter. If the light is flashing, we recommend that you replace the engine oil at an early opportunity depending on the driving and road conditions. If the light comes on, replace it as soon as possible.The system must be reset after the engine oil replacement. Reset the system by the following procedure: 1. Turn the ignition key to the ACC or LOCK position with the odometer reading shown. (For details, see Odometer and two trip meters on page 106 in this Section.) 2. Turn the ignition key to the ON position while holding down the trip meter reset knob. Hold down the knob for at least 5 seconds. The odometer indicates 000000 and the light goes off. If the system fails to reset, the light will continue flashing.I also have a copy of the '05 Vibe manual, I don't see the light mentioned there... Can anyone with an '05 Vibe confirm whether they have this light or not? Would be interesting to find out! It doesn't look like Toyota's system is as complex as GM's - seems to me like it just tracks mileage, whereas many of the GM systems take into consideration a number of factors. Nonetheless, anything to remind an owner that they need to change their oil is a good thing, regardless of the method it uses to figure out remaining oil life.It's good that Toyota finally added this feature. Not sure what vehicles they have it on, I have read about it in both the Prius and Matrix owner's manuals, probably many others have it. Perhaps they'll see fewer cars in the shop with 40,000 miles and the original oil filter.

[ToolGuy]

Interesting find CP!

[ColonelPanic]

I thought so too! Ahh, the things I find when I have nothing better to do than sit around and read owner's manuals for cars I do not own.