Understanding your PCV system and more
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Understanding your PCV system and more
The C5 and C6 are port injection and do not have the intake coking issues or as severe of fuel washdown, but still all good info. Education is key.
The PCV system and today's new engines:
Today's GDI engines have become the standard in the Automotive Industry, and this brings changes that the used vehicle market will be feeling the impact of in the coming years as far as longevity and reliability. One of the biggest impacts is the advancement of internal air/oil separation in order to reduce the rate and severity of intake valve coking. These internal separators do a very good job of spearating the il mist from the crankcase vapors prior to being ingested as part of the intake air charge. And in doing so, there is a trade off. While this has a significant impact on intake valve coking issues that have paluged the earlier GDI engines, this has also created another issue as the PCV system as we have known it histroically has also removed most of the wear causing combustion by-products, as well as providing pollution controll and the result, along with better oils, etc., has been longer and longer engine life. That has now changed as with this oil that is removed from the vapors and returned to the crankcase, the wear causing compounds are also returned overwhelming the engine oils ability to protect as well as in the past. Todays full synthetic oils don;t “wear out” as petroleum based oils of the past, they simply become overwhelmed with contaminants and eventually reach a point of no longer being able to provide the protection needed.
Each model and sub-model must compete in the marketplace against several other brands and cost controls are very strict. Even adding a $1 change costs $millions, and if already in production can be tens of $millions. One of the most frustrating parts of being an Engineer with any automaker, is you can have a great idea that addresses an issue or makes a sizable impact on improving a portion of a vehicle and it gets shot down by budget, legal, or marketing. So coming from the industry I know that frustration all to well.
So, understanding what the PCV system has historically done as far as critical functions, we have to look back prior to the mid 1960's. Before the PCV system was mandated, all engines simply "vented" (like some uneducated shops/tuners do now not understanding how damaging it is to the engine over time) the crankcase pressure and vapors through a "road draft tube" (Google any of this to learn more). And as there was no oil analysis, these engines, with oil change intervals of every 1200 miles, rarely went more than 30-50k miles before the entire engine needed to be rebuilt due to excessive wear. This wear was so severe we had to cut a "wear ridge" from each cylinder before we could even remove the pistons. Then, solely to reduce the ground water pollution from road runoff of the oil dripping from all vehicles, the Federal Government mandated the PCV system. What happened in the following years was a big puzzle. These same engines, using the same oils, and same change intervals were now going 100,000 miles plus before needing to be rebuilt. It was then discovered that the PCV system was removing the combustion by-products and other contaminants that prior were left in the crankcase and contaminated the engine oil overwhelming its ability to protect, and not these were being removed as soon as the entered before they had a chance to settle and mix with the oil. So, there are many critical functions the PCV systems have provided, only 1 being pollution related.
Now, we face the issues of intake valve coking, and as the average new vehicle owner only only keeps there car/truck 3 years on average, and put less than 50k miles on it, the goal is no longer longevity but to reduce the rate of coking prior to that 50k mile limit. And they are sacrificing engine wear and life to do so. They do NOT want warranty claims of owners coming in at 20-30k miles with misfires and off idle hesitation, etc. the coking eventually causes. As these are not hand built supercars and are mass produced, this is an acceptable trade off as the secondary, or used market is of little concern to the new car market. In fact, Government has been pushing to destroy and recycle vehicles to get them off the road and CA has been at the lead of doing this.
So, back to the new engines and the far more robust internal separation of the oil most from the crankcase vapors this is seen as an acceptable and necessary trade off. 99.9% of all new vehicle owners will never realize any of these issues as they purchase a car and expect to do nothing for the first 10k miles (and another horrible trend is NOT changing that debris and filing filled initial oil at 500 miles like is critical to do) except put fuel in. When a notice pops up on the dash telling them to visit the dealer for service is the only time most even think about maintenance and don't ever even open the hood.
Now, there is no reason these vehicles cannot live a long and useful life, but it requires more owner attention and action to do so. The emphasis has migrated to the comforts and technologies offered than long term use.
Times are a changing!
www.RXCatchcans.com
The PCV system and today's new engines:
Today's GDI engines have become the standard in the Automotive Industry, and this brings changes that the used vehicle market will be feeling the impact of in the coming years as far as longevity and reliability. One of the biggest impacts is the advancement of internal air/oil separation in order to reduce the rate and severity of intake valve coking. These internal separators do a very good job of spearating the il mist from the crankcase vapors prior to being ingested as part of the intake air charge. And in doing so, there is a trade off. While this has a significant impact on intake valve coking issues that have paluged the earlier GDI engines, this has also created another issue as the PCV system as we have known it histroically has also removed most of the wear causing combustion by-products, as well as providing pollution controll and the result, along with better oils, etc., has been longer and longer engine life. That has now changed as with this oil that is removed from the vapors and returned to the crankcase, the wear causing compounds are also returned overwhelming the engine oils ability to protect as well as in the past. Todays full synthetic oils don;t “wear out” as petroleum based oils of the past, they simply become overwhelmed with contaminants and eventually reach a point of no longer being able to provide the protection needed.
Each model and sub-model must compete in the marketplace against several other brands and cost controls are very strict. Even adding a $1 change costs $millions, and if already in production can be tens of $millions. One of the most frustrating parts of being an Engineer with any automaker, is you can have a great idea that addresses an issue or makes a sizable impact on improving a portion of a vehicle and it gets shot down by budget, legal, or marketing. So coming from the industry I know that frustration all to well.
So, understanding what the PCV system has historically done as far as critical functions, we have to look back prior to the mid 1960's. Before the PCV system was mandated, all engines simply "vented" (like some uneducated shops/tuners do now not understanding how damaging it is to the engine over time) the crankcase pressure and vapors through a "road draft tube" (Google any of this to learn more). And as there was no oil analysis, these engines, with oil change intervals of every 1200 miles, rarely went more than 30-50k miles before the entire engine needed to be rebuilt due to excessive wear. This wear was so severe we had to cut a "wear ridge" from each cylinder before we could even remove the pistons. Then, solely to reduce the ground water pollution from road runoff of the oil dripping from all vehicles, the Federal Government mandated the PCV system. What happened in the following years was a big puzzle. These same engines, using the same oils, and same change intervals were now going 100,000 miles plus before needing to be rebuilt. It was then discovered that the PCV system was removing the combustion by-products and other contaminants that prior were left in the crankcase and contaminated the engine oil overwhelming its ability to protect, and not these were being removed as soon as the entered before they had a chance to settle and mix with the oil. So, there are many critical functions the PCV systems have provided, only 1 being pollution related.
Now, we face the issues of intake valve coking, and as the average new vehicle owner only only keeps there car/truck 3 years on average, and put less than 50k miles on it, the goal is no longer longevity but to reduce the rate of coking prior to that 50k mile limit. And they are sacrificing engine wear and life to do so. They do NOT want warranty claims of owners coming in at 20-30k miles with misfires and off idle hesitation, etc. the coking eventually causes. As these are not hand built supercars and are mass produced, this is an acceptable trade off as the secondary, or used market is of little concern to the new car market. In fact, Government has been pushing to destroy and recycle vehicles to get them off the road and CA has been at the lead of doing this.
So, back to the new engines and the far more robust internal separation of the oil most from the crankcase vapors this is seen as an acceptable and necessary trade off. 99.9% of all new vehicle owners will never realize any of these issues as they purchase a car and expect to do nothing for the first 10k miles (and another horrible trend is NOT changing that debris and filing filled initial oil at 500 miles like is critical to do) except put fuel in. When a notice pops up on the dash telling them to visit the dealer for service is the only time most even think about maintenance and don't ever even open the hood.
Now, there is no reason these vehicles cannot live a long and useful life, but it requires more owner attention and action to do so. The emphasis has migrated to the comforts and technologies offered than long term use.
Times are a changing!
www.RXCatchcans.com
