What are the disadvantages of high oil viscosity?
2 Answers
Lubricating oil with excessive viscosity can lead to the following issues: High viscosity of lubricating oil results in poor fluidity, causing excessively high pressure at the oil pump outlet and an increase in the lubricating oil system pressure. It is advisable to adjust the lubricating oil pump, regulate the oil pressure, or blend in low-viscosity oil. When the oil pressure regulating valve fails, it should be repaired or replaced promptly. Oil may seep into the intake pushrods from the camshaft oil passages and mix into the combustion chamber to be consumed. When the viscosity is too high, the oil circulation rate decreases, leading to reduced cooling effectiveness and the formation of sludge and deposits. High viscosity results in a high friction coefficient, increased engine power loss, reduced output power, and higher fuel consumption.
I've encountered quite a few troubles when using engine oil with excessively high viscosity. Firstly, it significantly increases fuel consumption because the engine requires more effort to start and operate with this sticky oil, leading to higher fuel costs over time. Cold starts in winter are particularly painful - the oil flows poorly at low temperatures, making the starter motor labor hard. There were several instances when it took multiple attempts to get the engine running, which was terribly inconvenient. Moreover, internal engine wear intensifies as the oil film provides insufficient lubrication, potentially damaging components and even shortening engine lifespan in the long run. Additionally, emissions increase, and failing to meet exhaust standards might affect annual inspections. In conclusion, I strongly recommend selecting the proper viscosity as specified in the vehicle manual, rather than trying to save money or cut corners.
