Saab NINES Articles
Sludge
Maybe you are one of the fortunate car owners who doesn’t know what engine sludge is. There are several ways to describe this problem but generally we would say that when engine oil additives are depleted and oxidation residues combine with combustion, by products-- sludge and varnish are formed in the engine. During my research for this article, I have found that virtually every brand of car has had complaints about sludged engines. This would be when the volume of the material (sludge) would plug the oil pick-up screen, oil passages are plugged or impeded with the result of engine damage or failure. Toyota/Lexus probably has the largest documented problem today. Both V6 and 4 cylinder, built from 1996 to 2001, seem prone to these problems. Toyota sold about 3.3 million of these cars and had about 3,100 complaints. As a result of these complaints and publicity evoked, the warranties on these engines were extended to 8 years from the date-of-purchase (new) and unlimited miles in that time frame. This number of problems amounts to 1% of the total car sales. This is a significant group but certainly not overwhelming, however it might seem huge if you were one of the owners that had a problem. I read in AutoWeek 0n line that an engine replacement cost of $8,000 was being quoted to replace a Toyota engine before the warranty policy was changed. The description I read that was attributed to Toyota (still claims that they didn’t have a problem) was oil gelling that occurs when oil becomes contaminated, thicker, and no longer lubricates the engine and can lead to engine failure. Toyota claimed these problems were from extended oil changes only, yet many of the owners documented 4 to 6,000 mile oil changes. Chrysler also has a group of engines purported to be sludge-prone. Mercedes-Benz has had some problems as well. After having made a mistake in the owner’s manual, they corrected their oil recommendation to synthetic only. This only happened after the engine failures had begun. M-B has an oil monitoring system much like the new 9-3 that was calibrated for synthetic oil but recommended regular petroleum oil. As the result of a lawsuit the affected cars had their engine warranties extended to 150,000 miles.
It could happen to you! I would suggest that you re-read John Lippis’ and Steven Goldberger’s articles in NINES #261 about engine oil. I hope to give you more information that is basic and not as technical but will help you understand the danger that even your SAAB faces.
First of all, about 20% of the oil by volume is made up of the additives. These additives and the base stock oil carry 40% of the heat from combustion and friction inside the engine. The components in the additive package include detergents, sealers and corrosion inhibitors. Each oil company or brand combines a base stock and blend of additives to lubricate the engine and meets specific performance standards. These standards would meet and/or exceed those specifications stamped on the container in most cases. If you want to know which oil you should use, the label on the container should match what the Saab owner’s manual calls for. All engine oils are not the same.
In the chart I have provided, you can see in the test sequence shown that there is quite a difference in the performance of each of the brands tested. We are more interested in showing the differences in brands than how they performed in this particular test. The reason all of this matters is that under normal circumstances your engine oil, of the proper grade and weight, will be circulated throughout the engine lubricating, cooling, neutralizing sulfuric acids, (by-product of combustion) , condensation, carrying dirt, metal, etc, suspended in the oil back to the oil filter where it is deposited/trapped. Because of the temperatures encountered in the engine, oil degradation is a fact of life. Internal engine temperatures of 300 degrees are common with pistons reaching maybe 600 degrees and a turbo-charger could easily reach over a 1000 degrees. At about 475 degrees, petroleum-based oils will start to break down creating varnish and sludge that causes piston rings to stick, oil passages to be plugged, etc. If the oil is doing its job, the bad stuff will be dissolved, coated, floated, and carried to the oil filter where it is deposited and life goes on with no damage. This system works extremely well until we extend the oil change to the point that the oil filter has reached its capacity and the oil filter by-pass valve opens and, or the additive package has been depleted while doing it’s job. This allows the sludge and contamination to be recirculated through the engine again and again in the lubrication stream. The oil in this condition has become very abrasive and is systematically destroying the engine. Sludge forms as the car is driven and deposited throughout the engine. Excessive engine wear and reduced engine life is certainly the result. Keep operating for a period of time and engine failure is eminent. The solution is cheap and easy! Change the oil and filter!!!!
I know that the owner’s manual may say your car can go up to 10,000 miles between oil changes. I have a brochure from AMZOIL that says once a year or 25,000 miles works with one of their products. Most professionals in the auto-repair industry would suggest 3-5,000 miles regardless of the type of oil used and not go more than 4 months regardless of miles. It all depends on your driving habits, oil choice and climate. There is a scientific way to decide how far you can safely go between oil changes. The best would be to have an oil analysis done (see NINES #251, page 30 by Douglas Pond). Another way is to try the new OilMedic 5-minute test kit. This is a do-it-yourself test that they advertise for $2. The test is done simply by removing the dipstick from your engine and putting a drip of oil from the stick on the test paper. The oil condition is determined by the color and contamination their test paper demonstrates over a period of time. I haven’t been able to get a hold of one of these yet, but I think the kit has some merit. You can find the test kit on internet at www.oilmedic.com.
What if you have already neglected your engine? There are solutions to removing sludge and varnish without removing any engine parts. There are engine oil additives that can be added to the oil and run just before the oil change. These additives theoretically and practically dissolve the deposits (sludge & varnish) and carry them to the oil filter. The problem with this is that if the filter is full or gets full while you are using this process you will be circulating the sludge through your engine. If using one of these products follow the directions and don’t be afraid to change the oil filter one or more times in the process. What’s a few dollars for oil filters as opposed to the price of an engine?
The preferred method to remove suspected or proven sludge is to use an engine oil flush machine. We purchased one of these machines from BG Corp. for our shop to deal with the rising number of dirty engines we were encountering. The procedure for the engine oil flush is as follows: the engine is brought up to operating temp, then engine oil is drained and refilled. The engine is run again and brought up to operating temp, and the engine oil filter is then removed and an adapter is put in its place. Hoses are attached to the adapter feeding the engine oil under pressure (car engine idling) to a new high performance oil filter in the machine. A quart of Engine Purge is added to the oil. This mixture flushes the sludge and varnish out of the engine and to the machine’s filter. The car engine is being run at 1200 to 1500 rpm and the oil is circulating for 20 minutes. There is a flow gauge on the machine so the operator can verify that the oil screen is not plugged and that the engine will not be damaged. The engine is shut off, oil drained and then air pressure is applied to the oil system to push out any remaining oil and contaminants. A new engine oil filter is installed and new oil with a quart of additive is installed with the machine into the engine under pressure to thwart a dry engine start. This procedure costs less than $130 and can be done whether your engine has been sludged or not. BG will warranty your engine if you start with their flush program on a car with less than 36 k miles or 3 years old for 7 years or 150k miles. We believe that we have saved a number of engines that have had near-fatal symptoms with the flush.
I have included pictures of an engine from a 99 9-5 with 65K miles on it. It was much too late for this SAAB. For demonstration purposes, we removed the oil pan before flushing this engine. The symptoms were blue exhaust smoke, oil light flickering on and off at idle, hydraulic lifters rattled from time-to-time and the timing and balance shaft chains rattled like crazy. Upon removal of the oil pan and pick-up screen, we found that there was a mound of debris plugging the screen. The debris was semi-solid and felt like sand between my fingers. We scraped this out of the pan. It was about a 1/4 cup full. We re-installed the oil pan and pick-up screen and did the engine flush procedure. We removed the oil pan and pick-up screen again, and as we expected we were able to remove a large amount of sludge with the flush. The problem we were able to prove was that some of the debris which was not soluble and quite heavy ended up in the bottom of the oil pan. Upon some disassembly and inspection of the engine parts and debris, we decided that most of the debris was from the timing chain slides and some was deteriorated rubber hose. The oil additives could not dissolve these and they were too heavy to carry to the filter, too big to go through the oil screen and were left in the oil pan. If an engine is suspected of approaching this condition, the oil could be drained and a probe inserted through the oil pan drain hole. With the probe, the debris could be loosened and possibly flushed out the drain hole by using a solvent like diesel poured through the engine. The material coming through the drain plug can be examined to determine what the situation is. A large amount of debris would certainly warrant disassembly to find out what parts had failed or are failing. After any investigation like this or intrusion of solvents into the engine, we would always perform a flush to get all loose gunk and solvent out. We would never, ever run the engine with any solvent in the pan.
Back to our 9/5 engine: We removed main bearing caps, and plastigaged the bearings and found them to be worn out of spec and the crankshaft was scored as well as the oil pump. There was no reason to do any further disassembly since the damage was terminal. We replaced the engine.
How much do you think was saved on oil changes or the lack, thereof? If you have an engine that you suspect or that has been damaged, don’t throw the towel in before trying some of the flushing procedures. My best advice to you is to use good oil and change it often. Refer to the previous Nines articles for help if you want oil type recommendations. I can’t think of better insurance than that! If some of you are under factory warranty or have service contracts, be sure to keep records of all of your service so if you have a problem you have documentation. We have heard rumors of warranty/service claims being denied because of sludging. Don’t let it happen to you!
Oil service is a huge subject that I have tried to boil down into a short dissertation. There are many sources that have exhaustive information on this subject. If you have more questions, there are many practical and technical papers that can be found on the internet under "Engine oil sludge" on the internet. A Google search will yield 20k entries under that heading alone.