Understanding Oil Contaminants
Before I get into this month’s article, I want to remind everyone that the Great American Truck is coming up August 22nd to 24th at the Kay Bailey Hutchinson Convention Center in Dallas. If you haven’t made plans to attend, I suggest you register at: www.truckshow.com . Congratulations if you have already registered, you truly must understand the value of attending a truck show. Stop by the OPS-Oil Purification Systems booth 1012 and I will gladly discuss oil sampling and oil related issues with you. I hope to see you there.
How do you know if you need to overhaul your engine? Will an oil sample provide the answer for you? In the case of normal wear, the sample results will give you an indication that an overhaul is due by increases in wear metals, soot, and fuel etc. Overhaul may be required due to fracture of internal parts that may or may not be detected by an oil sample, but the majority of overhauls are due to normal wear over time.
Increases in iron wear coupled with lead copper and/or aluminum would indicate that bearings have worn down through the outer layers and are due for replacement. Most engine bearings consist of 3 layers of metals a Babbitt metal that is made up primarily of a lead, nickel, tin, copper overlay, a second layer of copper or aluminum held in place with a steel backing ring. Any worn bearings would not properly protect the iron parts and the iron wear would be accelerated etc. Don’t panic if you have high lead on a sample as the lead is the outer material and is sacrificial. It is intended to wear in place of iron etc., likewise if you have high copper but low lead wear it is probably not a bearing but leaching of the copper tubing in oil cooler. In any case before you spend thousands on an overhaul make sure you get a reputable shop to inspect engine and don’t rely solely on oil sample results. For all you know the air compressor bearings could be shot and you only need to replace it.
Increases in iron, chromium, soot, fuel and nitration would most likely indicate a broken or defective ring that is scoring a cylinder wall. The defective ring will reduce compression and increase blow-by and create soot from unburned fuel. The raw fuel does not compress properly and passes through rings into the oil as does the exhaust gasses that increase nitration. You would also see increased fuel consumption and lower MPG as fuel will not properly ignite. You may need to sleeve the cylinders and replace rings if wear is excessive.
If your oil shows signs of antifreeze (sodium and potassium) it may indicate that you have a cracked head gasket or head. It could also indicate a leaking oil cooler or EGR valve. In any event if you are adding coolant constantly and it is mixing with oil you should have system checked and repaired as soon as possible. The antifreeze reacts with zinc, the anti- wear additive in oil that prevents metal to metal wear. Failure to stop this intrusion over time will lead to costly repairs up to and including overhaul or a complete engine replacement.
The oil sample results can tell you a lot about the inner workings of your engine, but you should take the time to speak with lab or oil sample expert before making any serious and costly repairs.
I hope to see you at GATS. We will be in OPS-Oil Purification booth 1012, stop by if you are attending the show. If you have any topics you would like discussed in this column, please email me: [email protected]