National Oil & Lube News

February 2017

Digital issues of National Oil & Lube News, the trade magazine for the preventive maintenance industry

Issue link:

Contents of this Issue


Page 56 of 67

February 2017 | NOLN 57 Where applicable, extended life oil filters should be used on vehicles that are serviced at extended oil drain intervals. If not, filter bypass can occur. When this oc- curs, contaminated oil is flowing through the engine. For vehicles not equipped with a "Maintenance Re- minder," make certain you determine if the customer is operating the vehicle under normal or severe service conditions. Most will be surprised to learn they oper- ate their vehicle under severe conditions. Severe Service: 1) Vehicles driven for short distances of five miles or less, results in the oil not reaching its normal operat- ing temperature, which is necessary to burn off con- densation. 2) Vehicles driven 10 miles or less at temperatures be- low freezing 3) Vehicles that encounter extended periods of idling or slow-speed driving such as police cars, taxis, deliv- ery vehicles or vehicles operated in heavy traffic con- ditions 4) Vehicles driven in hot ambient temperatures (above 90 degrees F), especially in heavy traffic 5) Dusty conditions 6) Muddy, sandy, salt-spread or rough road conditions 7) Extended driving while exceeding normal highway speeds 8) Frequent starting and stopping Gasoline Direct Injection e gasoline direct injection (GDI) system injects fuel directly into the combustion chamber at pressures that can exceed 2,000 psi. Unlike a port fuel injection (PFI) system, the GDI system does not spray fuel directly onto the intake valves, resulting in the formation of carbon deposits on the intake valves because of the absence of the fuel wash. Fuel additives placed in the fuel tank offer no benefit to the intake valves on the GDI system. Intake valve contamination occurs because of the following events: e crankcase is purged via a positive crankcase ventila- tion (PCV) valve, and the vapors are routed through the intake manifold and intake valves where they are consumed in the com- bustion process. During this purging event, the intake valves are subjected to oil vapors, which get baked onto the valves. Oil seep- age past the intake valve guides and seals contribute to the same. High-mileage engines with excessive wear promote a faster accu- mulation of the deposits. Exhaust gas recirculation (EGR) further aggravates the condition. Preventive Maintenance Examining an engine for excessive intake valve deposits and the removal of the deposits can be labor intensive, often requiring the removal of the intake manifold and cylinder heads. To prevent the contamination from getting to the level that the valves are total- ly encrusted and making a clean-up difficult, we recommend an annual intake cleaning. is should be performed once a year or every 15,000 miles to minimize the formation of the carbon de- posits. e cleaning process involves introducing chemicals into the intake manifold down-stream of the mass airflow sensor. is treatment can minimize the formation of the carbon deposits. Once heavy deposits accumulate, cleaning can result in large frag- ments breaking loose, causing piston or cylinder wall damage. A little attention to preventive maintenance can save the cus- tomer a lot of unnecessary repair cost. S LARRY HAMMER is an automotive troubleshooter who oversees Mighty's Technical Sup- port Services in Jackson, Tennessee. Hammer has been writing technical articles since 1982. He may be reached at: Figure 1 Figure 2

Articles in this issue

Links on this page

view archives of National Oil & Lube News - February 2017