My gen 1 3.5 Ecoboost; An inauspicious Start

Joined
Dec 27, 2022
Messages
9
A story about a neglected engine and how it, thus far, has survived. Mostly by dead reckoning and good fortune, less so with measurable science. Am sure some will crow, but hopefully some constructive ideas will be shared to help others in similar situations.

In Feb 2021, an acquaintance was selling his 2012 F150 xlt ecoboost to fund purchase of an F250 he wanted for pulling a large camper. A short haul trucker, his F150 was always clean, no damage, 100k mi, driven about 100 interstate miles per day for work and usual in-town errands for two years he had it. Prior history unknown but for one-owner. “Needed a new crank sensor recently. Always use Mobil 1 5w30 every 5k mi,” he advised. He boasted how he would commonly hit the remote start 2-3x each morning while got ready for work, particularly in cold months; he’s used to diesels, however. My only hesitation was anticipating the inevitable need for a timing chain.

Was working 4hr from home weekdays, a nice all-highway rural trip and needed to replace my old commuter as well as wanting a truck for recreational towing myself, I bought it for $22k. Truck drove fantastic except that under heavy load to pass there was sometimes a hard stumble. Researched it. Did the intercooler drain hole mod. The CPS had already been changed. At 101k, took to a shop. Almost certainly the timing chain, they say. They tear it down, and I get the call: “I’m sorry, I remember you said you bought this truck from a friend, but you got screwed. The tech says it’s the most sludged top-end he’s ever seen, and the engine is probably beyond saving. Since it is all apart already, my advice is we’ll scrape clean what we can, replace the timing chain, and you drive it straight to a CarMax and dump it for something else.” Really? Great…. The shop recommended against running a cleaner in it, but conceded sometimes such an engine has “gone on a long time” on frequent synth oil changes, but not to get your hopes up - sell it.

I otherwise loved the truck, and really couldn’t afford ANOTHER vehicle purchase yet. I researched that a new engine is about $10k plus labor. I weigh what my loss would be to sell now (low) and buy something comparable (high) in present market, and decide to roll the dice, keeping truck. Had them do the water pump and clean the pan/oil pickup, too, which they said was relatively clean fortunately. Not realizing the oil pump was accessible, I neglected to upgrade that.

My trips were 250mi each way, highway, maybe one stop to stretch. Dumped the repair shop’s oil and started every 500mi oil and filter changes. Early on, some soft bits of skin-like bits, fingernail sized, came out in the pan. Cut open filters; burden of large black flake material ranging from sand to 2mm each, filling valley of pleats to ballpark 15%-%20. Nothing metallic-appearing, nothing attracted by a magnet. Used Walmart Royal Purple 5w30 and K&N Select filters initially, based on old recollections. After some more current reading on BITOG revealed that neither was a great choice perhaps, switched to PUP 5w30 and later 0W40, the latter the SRT stuff until turned on to the Euro; and Napa Gold and later Wix XP’s filters. As the filter media burden slacked, I worked up the OCI until hit 3,300mi, then stuck with that. Interestingly, over time the PUP/Euro came out at 3,300mi as clean looking as it went in. Initially took this to mean the engine was more/less cleaned up. Or so I thought…. P.S. the 3,300mi OCI based on youtuber maculoco’s recommendation re: this engine and timing chain wear.
Truck ran great. Pulled an 18ft camper, a three place snowmobile trailer, a 14ft enclosed trailer, firewood and sundries in the mountains regularly. The time I was spending fiddling with oil changes year round was getting old, however. Was following along on BITOG. At 130k mi, learned about HPL, and the notion of a top-shelf oil formulation with a history of success in my engine family, potentially with longer OCI ability in hard-use GDI engines caught my attention.

Before switching, I used Castrol synth 0W40 and one quart of HPL EC, changing filter at 1k and OCI every 2k. The amount of trash in the filter media skyrocketed to even MORE than when first started this saga, about 20-25% of the filter valley. Continued for 5 rounds/10k mi through this last fall; the filter media burden is a fine black sand to flat-flake material sub-1mm. This whole time, only once (gulp), did a 8mm long thin shaving of non-ferrous metal debris show up in the drain pan. The debris amount waned slightly over that 10k miles. I had begun living in my work-town though with no garage and winter coming. Decided to change to all HPL, hoping to just change filters in the snow, not whole oil changes, for a stretch.

It would be interesting: I should measure the compression and oil pressure on this engine; all i know today is the oil pressure gauge reads about 60% of arc (assume that’s around 40-50psi) and no appreciable losses on dipstick. Still I assume this engine has at least higher than average wear if it was torn down. Therefore, chose to stick with 0/5W40 going forward, looking for a robust HTHS. Picked the 0W40 HPL Premium Plus for winter, for no reason other than appeared to have the best cold crank properties (the wind blown barren west where -40F is normal for stretches; yes, use a block heater). This spring, have standard 5W40 PCMO set aside for the warm months.

Went the first 5k this winter changing filters every 1k. Used Mobil 1 212A’s. The burden in filter slightly decreased, now have gone to 1250mi OCI for the present interval. Am at 146,900mi today. My goal is to continue 5k OCI and slowly extend filter change intervals, hoping to get to 5k filter changes some day…. Have pondered about a more measurable, objective way to determine the trend in filter debris, but given filter-to-filter variance in weight, have not come up with anything better than eye-ball.

I appreciate this story is giving some the shivers. Just be glad it’s not your problem! Suggestions and discussion welcomed; am just a guy, mechanically inclined but not a mechanic, nor an engineer.

Summary:
- It’s unfortunate the factual condition of the truck proved to be, and that a “friend” did this to me. But, that’s life.
- The reputation of the gen 1 exoboost is accurate IMO, both the good and bad: powerful/stout, prone to sludge with idling and short-tripping. Evidently, this example of one suggests it is a fairly robust design none the less.
- Am not saying the Mobil 1 5W30 is at fault, as suspect it was short tripping, excessive idling, and too long OCI to blame, but none the less am dissuaded from Mobil in this engine at least until it’s fully cleaned up and stops shedding.
- PUP. My impression is, this GTL oil may be very clean, but it itself doesn’t clean much.
- HPL EC performed as advertised. A steady but manageable amount of engine carbon debris was consistently liberated.
- I lose sleep over how much carbonaceous debris gets past the filter and may be accelerating wear, but short of adding a bypass filter I don’t have any answers. You?
- Point of clarity: If I wasn’t aiming to change over to HPL oil with the goal of longer OCI, i likely could have stuck with PUP Euro 0W40 and left the deposits where they lie, I realize. But moving to HPL forecast I would need to manage the loosened debris until such time it was all gone, which is anyone’s guess, and maybe a fool’s errand. Hard to say yet.
- My last filter is waiting to be cut open. Will post pic when have a minute.
- Gratefully, have gotten another 46k mi and counting out of a truck that was written off. The turbos reputedly go 150k-250k, and the engines 250k-300k per internet. Going to be interesting to see how this example does.
- Still looking for a shop in rural America to do my intake valve cleaning (on general principle). I even bought the machine/supplies, but haven’t the experience/down-time/shop space to do myself right now.
 
It sounds like you are rehabilitating the engine slowly and carefully. The only piece of information I can provide is that the "oil pressure" gauge is just a dummy switch. If you have more than 7psi of oil pressure the gauge will stay where it always stays. Less than 7psi it goes to zero. It's not reading actual oil pressure in a range, just a switch that energizes above 7psi, which is why you never see any fluctuations. Ford has been using this method for quite a while as moving oil gauges frightened owners too much.
 
- I lose sleep over how much carbonaceous debris gets past the filter and may be accelerating wear, but short of adding a bypass filter I don’t have any answers. You?
Carbon deposits getting past the filter shouldn't be abrasive enough to cause meaningful wear, but if this engine has any oil screens for the turbos or VVT system, they could get clogged, so I would clean or replace them.

The oil pump pickup screen could be loaded with debris as well. If it was bad enough, it would reduce oil pressure, but keep in mind that if oil passages and screens are a bit clogged up, that will increase oil pressure, so normal oil pressure isn't necessarily a sign that everything is fine with the pickup screen. I'd try to check it with a boroscope if that's possible on these engines. If not, maybe plan to drop the oil pan again at some point to clean the pan and pickup again.

The NAPA Gold and WIX XP filters are a good choice since they have low restriction and a high holding capacity. Using an oversized filter could help prevent bypassing, or could allow less frequent filter changes.
 
Quite a write up!

I do get the impression from what you wrote that the truck may have been severely neglected by the first owner and your friend was unaware of it.

Anyway, you have been doing great with it. Cut and posts of those filters would have been interesting!
 
i didnt wanna read it all so i pasted into chat gpt and asked it to summarize:

"The user shares a story about purchasing a 2012 F150 xlt ecoboost, initially in good condition but later discovered to have engine issues. Despite recommendations to sell, they decide to keep the truck and undertake extensive oil and filter maintenance, including using various oils and additives. The user's switch to HPL oil appears to have helped manage engine carbon debris. They express concerns about the long-term impact of carbon debris on engine wear but continue to drive the truck, which has surpassed expectations in mileage. The user is also seeking a shop for intake valve cleaning."
 
Top down:
1. Early oil changes RP & PUP 5W30 filters, 500-1500mi OCI
2. Penz Euro 0W40 filters, 3,300mi OCI filters (oil was coming out rather clean appearing and lesser carbon debris)
3. Castrol synth 0W40 + HPL EC

Last filter/single strip:
4. At about 6800mi of HPL Premium Plus 0W40, 1k mi filter changes, now this example after oil change at 5k, and first 1250mi filter change. Media has sat a week but still damp (dark), sorry
IMG_9540.jpeg
 
"I thought about changing the mobil 1 every 5000 miles"
turned into "I changed the oil religiously every 5000 miles."
:unsure:
 
Looks like there are some metal sparkles in the filter as well, but nothing I'd be too concerned about. What's the oil consumption like? Has it changed at all after using the HPL?
 
Looks like there are some metal sparkles in the filter as well, but nothing I'd be too concerned about. What's the oil consumption like? Has it changed at all after using the HPL?
Haven’t been able to discern any oil loss, though not a high bar when changing filters and topping off at 1k or 1.25k miles. Didn’t have losses with PUP at 3,300mi, fwiw. Will watch.

Sure it was Mobil 1 used and not Mobil 2?
Right?
 
A story about a neglected engine and how it, thus far, has survived. Mostly by dead reckoning and good fortune, less so with measurable science. Am sure some will crow, but hopefully some constructive ideas will be shared to help others in similar situations.

In Feb 2021, an acquaintance was selling his 2012 F150 xlt ecoboost to fund purchase of an F250 he wanted for pulling a large camper. A short haul trucker, his F150 was always clean, no damage, 100k mi, driven about 100 interstate miles per day for work and usual in-town errands for two years he had it. Prior history unknown but for one-owner. “Needed a new crank sensor recently. Always use Mobil 1 5w30 every 5k mi,” he advised. He boasted how he would commonly hit the remote start 2-3x each morning while got ready for work, particularly in cold months; he’s used to diesels, however. My only hesitation was anticipating the inevitable need for a timing chain.

Was working 4hr from home weekdays, a nice all-highway rural trip and needed to replace my old commuter as well as wanting a truck for recreational towing myself, I bought it for $22k. Truck drove fantastic except that under heavy load to pass there was sometimes a hard stumble. Researched it. Did the intercooler drain hole mod. The CPS had already been changed. At 101k, took to a shop. Almost certainly the timing chain, they say. They tear it down, and I get the call: “I’m sorry, I remember you said you bought this truck from a friend, but you got screwed. The tech says it’s the most sludged top-end he’s ever seen, and the engine is probably beyond saving. Since it is all apart already, my advice is we’ll scrape clean what we can, replace the timing chain, and you drive it straight to a CarMax and dump it for something else.” Really? Great…. The shop recommended against running a cleaner in it, but conceded sometimes such an engine has “gone on a long time” on frequent synth oil changes, but not to get your hopes up - sell it.

I otherwise loved the truck, and really couldn’t afford ANOTHER vehicle purchase yet. I researched that a new engine is about $10k plus labor. I weigh what my loss would be to sell now (low) and buy something comparable (high) in present market, and decide to roll the dice, keeping truck. Had them do the water pump and clean the pan/oil pickup, too, which they said was relatively clean fortunately. Not realizing the oil pump was accessible, I neglected to upgrade that.

My trips were 250mi each way, highway, maybe one stop to stretch. Dumped the repair shop’s oil and started every 500mi oil and filter changes. Early on, some soft bits of skin-like bits, fingernail sized, came out in the pan. Cut open filters; burden of large black flake material ranging from sand to 2mm each, filling valley of pleats to ballpark 15%-%20. Nothing metallic-appearing, nothing attracted by a magnet. Used Walmart Royal Purple 5w30 and K&N Select filters initially, based on old recollections. After some more current reading on BITOG revealed that neither was a great choice perhaps, switched to PUP 5w30 and later 0W40, the latter the SRT stuff until turned on to the Euro; and Napa Gold and later Wix XP’s filters. As the filter media burden slacked, I worked up the OCI until hit 3,300mi, then stuck with that. Interestingly, over time the PUP/Euro came out at 3,300mi as clean looking as it went in. Initially took this to mean the engine was more/less cleaned up. Or so I thought…. P.S. the 3,300mi OCI based on youtuber maculoco’s recommendation re: this engine and timing chain wear.
Truck ran great. Pulled an 18ft camper, a three place snowmobile trailer, a 14ft enclosed trailer, firewood and sundries in the mountains regularly. The time I was spending fiddling with oil changes year round was getting old, however. Was following along on BITOG. At 130k mi, learned about HPL, and the notion of a top-shelf oil formulation with a history of success in my engine family, potentially with longer OCI ability in hard-use GDI engines caught my attention.

Before switching, I used Castrol synth 0W40 and one quart of HPL EC, changing filter at 1k and OCI every 2k. The amount of trash in the filter media skyrocketed to even MORE than when first started this saga, about 20-25% of the filter valley. Continued for 5 rounds/10k mi through this last fall; the filter media burden is a fine black sand to flat-flake material sub-1mm. This whole time, only once (gulp), did a 8mm long thin shaving of non-ferrous metal debris show up in the drain pan. The debris amount waned slightly over that 10k miles. I had begun living in my work-town though with no garage and winter coming. Decided to change to all HPL, hoping to just change filters in the snow, not whole oil changes, for a stretch.

It would be interesting: I should measure the compression and oil pressure on this engine; all i know today is the oil pressure gauge reads about 60% of arc (assume that’s around 40-50psi) and no appreciable losses on dipstick. Still I assume this engine has at least higher than average wear if it was torn down. Therefore, chose to stick with 0/5W40 going forward, looking for a robust HTHS. Picked the 0W40 HPL Premium Plus for winter, for no reason other than appeared to have the best cold crank properties (the wind blown barren west where -40F is normal for stretches; yes, use a block heater). This spring, have standard 5W40 PCMO set aside for the warm months.

Went the first 5k this winter changing filters every 1k. Used Mobil 1 212A’s. The burden in filter slightly decreased, now have gone to 1250mi OCI for the present interval. Am at 146,900mi today. My goal is to continue 5k OCI and slowly extend filter change intervals, hoping to get to 5k filter changes some day…. Have pondered about a more measurable, objective way to determine the trend in filter debris, but given filter-to-filter variance in weight, have not come up with anything better than eye-ball.

I appreciate this story is giving some the shivers. Just be glad it’s not your problem! Suggestions and discussion welcomed; am just a guy, mechanically inclined but not a mechanic, nor an engineer.

Summary:
- It’s unfortunate the factual condition of the truck proved to be, and that a “friend” did this to me. But, that’s life.
- The reputation of the gen 1 exoboost is accurate IMO, both the good and bad: powerful/stout, prone to sludge with idling and short-tripping. Evidently, this example of one suggests it is a fairly robust design none the less.
- Am not saying the Mobil 1 5W30 is at fault, as suspect it was short tripping, excessive idling, and too long OCI to blame, but none the less am dissuaded from Mobil in this engine at least until it’s fully cleaned up and stops shedding.
- PUP. My impression is, this GTL oil may be very clean, but it itself doesn’t clean much.
- HPL EC performed as advertised. A steady but manageable amount of engine carbon debris was consistently liberated.
- I lose sleep over how much carbonaceous debris gets past the filter and may be accelerating wear, but short of adding a bypass filter I don’t have any answers. You?
- Point of clarity: If I wasn’t aiming to change over to HPL oil with the goal of longer OCI, i likely could have stuck with PUP Euro 0W40 and left the deposits where they lie, I realize. But moving to HPL forecast I would need to manage the loosened debris until such time it was all gone, which is anyone’s guess, and maybe a fool’s errand. Hard to say yet.
- My last filter is waiting to be cut open. Will post pic when have a minute.
- Gratefully, have gotten another 46k mi and counting out of a truck that was written off. The turbos reputedly go 150k-250k, and the engines 250k-300k per internet. Going to be interesting to see how this example does.
- Still looking for a shop in rural America to do my intake valve cleaning (on general principle). I even bought the machine/supplies, but haven’t the experience/down-time/shop space to do myself right now.
I would buy a case of HPL EC30, use 1 quart with every oil change. After 6 oil changes, go to HPL PCMO 5W-30. After a few years of doing that, consider switching to any low priced full synthetic 5W-30.
 
A story about a neglected engine and how it, thus far, has survived. Mostly by dead reckoning and good fortune, less so with measurable science. Am sure some will crow, but hopefully some constructive ideas will be shared to help others in similar situations.

In Feb 2021, an acquaintance was selling his 2012 F150 xlt ecoboost to fund purchase of an F250 he wanted for pulling a large camper. A short haul trucker, his F150 was always clean, no damage, 100k mi, driven about 100 interstate miles per day for work and usual in-town errands for two years he had it. Prior history unknown but for one-owner. “Needed a new crank sensor recently. Always use Mobil 1 5w30 every 5k mi,” he advised. He boasted how he would commonly hit the remote start 2-3x each morning while got ready for work, particularly in cold months; he’s used to diesels, however. My only hesitation was anticipating the inevitable need for a timing chain.

Was working 4hr from home weekdays, a nice all-highway rural trip and needed to replace my old commuter as well as wanting a truck for recreational towing myself, I bought it for $22k. Truck drove fantastic except that under heavy load to pass there was sometimes a hard stumble. Researched it. Did the intercooler drain hole mod. The CPS had already been changed. At 101k, took to a shop. Almost certainly the timing chain, they say. They tear it down, and I get the call: “I’m sorry, I remember you said you bought this truck from a friend, but you got screwed. The tech says it’s the most sludged top-end he’s ever seen, and the engine is probably beyond saving. Since it is all apart already, my advice is we’ll scrape clean what we can, replace the timing chain, and you drive it straight to a CarMax and dump it for something else.” Really? Great…. The shop recommended against running a cleaner in it, but conceded sometimes such an engine has “gone on a long time” on frequent synth oil changes, but not to get your hopes up - sell it.

I otherwise loved the truck, and really couldn’t afford ANOTHER vehicle purchase yet. I researched that a new engine is about $10k plus labor. I weigh what my loss would be to sell now (low) and buy something comparable (high) in present market, and decide to roll the dice, keeping truck. Had them do the water pump and clean the pan/oil pickup, too, which they said was relatively clean fortunately. Not realizing the oil pump was accessible, I neglected to upgrade that.

My trips were 250mi each way, highway, maybe one stop to stretch. Dumped the repair shop’s oil and started every 500mi oil and filter changes. Early on, some soft bits of skin-like bits, fingernail sized, came out in the pan. Cut open filters; burden of large black flake material ranging from sand to 2mm each, filling valley of pleats to ballpark 15%-%20. Nothing metallic-appearing, nothing attracted by a magnet. Used Walmart Royal Purple 5w30 and K&N Select filters initially, based on old recollections. After some more current reading on BITOG revealed that neither was a great choice perhaps, switched to PUP 5w30 and later 0W40, the latter the SRT stuff until turned on to the Euro; and Napa Gold and later Wix XP’s filters. As the filter media burden slacked, I worked up the OCI until hit 3,300mi, then stuck with that. Interestingly, over time the PUP/Euro came out at 3,300mi as clean looking as it went in. Initially took this to mean the engine was more/less cleaned up. Or so I thought…. P.S. the 3,300mi OCI based on youtuber maculoco’s recommendation re: this engine and timing chain wear.
Truck ran great. Pulled an 18ft camper, a three place snowmobile trailer, a 14ft enclosed trailer, firewood and sundries in the mountains regularly. The time I was spending fiddling with oil changes year round was getting old, however. Was following along on BITOG. At 130k mi, learned about HPL, and the notion of a top-shelf oil formulation with a history of success in my engine family, potentially with longer OCI ability in hard-use GDI engines caught my attention.

Before switching, I used Castrol synth 0W40 and one quart of HPL EC, changing filter at 1k and OCI every 2k. The amount of trash in the filter media skyrocketed to even MORE than when first started this saga, about 20-25% of the filter valley. Continued for 5 rounds/10k mi through this last fall; the filter media burden is a fine black sand to flat-flake material sub-1mm. This whole time, only once (gulp), did a 8mm long thin shaving of non-ferrous metal debris show up in the drain pan. The debris amount waned slightly over that 10k miles. I had begun living in my work-town though with no garage and winter coming. Decided to change to all HPL, hoping to just change filters in the snow, not whole oil changes, for a stretch.

It would be interesting: I should measure the compression and oil pressure on this engine; all i know today is the oil pressure gauge reads about 60% of arc (assume that’s around 40-50psi) and no appreciable losses on dipstick. Still I assume this engine has at least higher than average wear if it was torn down. Therefore, chose to stick with 0/5W40 going forward, looking for a robust HTHS. Picked the 0W40 HPL Premium Plus for winter, for no reason other than appeared to have the best cold crank properties (the wind blown barren west where -40F is normal for stretches; yes, use a block heater). This spring, have standard 5W40 PCMO set aside for the warm months.

Went the first 5k this winter changing filters every 1k. Used Mobil 1 212A’s. The burden in filter slightly decreased, now have gone to 1250mi OCI for the present interval. Am at 146,900mi today. My goal is to continue 5k OCI and slowly extend filter change intervals, hoping to get to 5k filter changes some day…. Have pondered about a more measurable, objective way to determine the trend in filter debris, but given filter-to-filter variance in weight, have not come up with anything better than eye-ball.

I appreciate this story is giving some the shivers. Just be glad it’s not your problem! Suggestions and discussion welcomed; am just a guy, mechanically inclined but not a mechanic, nor an engineer.

Summary:
- It’s unfortunate the factual condition of the truck proved to be, and that a “friend” did this to me. But, that’s life.
- The reputation of the gen 1 exoboost is accurate IMO, both the good and bad: powerful/stout, prone to sludge with idling and short-tripping. Evidently, this example of one suggests it is a fairly robust design none the less.
- Am not saying the Mobil 1 5W30 is at fault, as suspect it was short tripping, excessive idling, and too long OCI to blame, but none the less am dissuaded from Mobil in this engine at least until it’s fully cleaned up and stops shedding.
- PUP. My impression is, this GTL oil may be very clean, but it itself doesn’t clean much.
- HPL EC performed as advertised. A steady but manageable amount of engine carbon debris was consistently liberated.
- I lose sleep over how much carbonaceous debris gets past the filter and may be accelerating wear, but short of adding a bypass filter I don’t have any answers. You?
- Point of clarity: If I wasn’t aiming to change over to HPL oil with the goal of longer OCI, i likely could have stuck with PUP Euro 0W40 and left the deposits where they lie, I realize. But moving to HPL forecast I would need to manage the loosened debris until such time it was all gone, which is anyone’s guess, and maybe a fool’s errand. Hard to say yet.
- My last filter is waiting to be cut open. Will post pic when have a minute.
- Gratefully, have gotten another 46k mi and counting out of a truck that was written off. The turbos reputedly go 150k-250k, and the engines 250k-300k per internet. Going to be interesting to see how this example does.
- Still looking for a shop in rural America to do my intake valve cleaning (on general principle). I even bought the machine/supplies, but haven’t the experience/down-time/shop space to do myself right now.
You may wish to run a carfax. It frequently tells you when, where, and at what mileage the oil changes were done if they were done at a dealership or chain store place.
 
You may wish to run a carfax. It frequently tells you when, where, and at what mileage the oil changes were done if they were done at a dealership or chain store place.
It’s almost guaranteed to be a waste of money if his friend also lives in the rural area, and didn’t have the oil changes done at a Ford dealer or other major chain. Save the money, he’s already into the truck for 46k miles since purchase!
 
46k miles into a paid-for truck that was told to junk, so really have no complaints, but to share the story.

Bill7: pretty much what i did. Think will stick with HPL indefinitely, though. Be interesting to see how long truck holds together on it.
 
Didn't see any mention of changing out the PCV or enduring the crankcase ventilation system is operating well. If the nasty crankcase byproducts are not properly evacuated, that can cause oil degradation and deposits to build up.
 
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