This isn't rocket surgery. Give it a good nnnnnngghhhhhh with one hand and move on with your life. This seems like either a freak occurrence with the gasket or Murphy's Law.
Pentius UFXL PLXL7317 O-Ring gasket failure.
- Thread starter Samurai1225
- Start date
I didn't read all of the posts here, but my questions are: who performed the last oil change and are you sure the filter was properly tightened? I know from my own stash that this Pentius filter has a flat type silicone gasket, not a P type gasket. It's hard to imagine the gasket blowing out on a properly installed oil filter.
Post-Mortem & Lessons Learned
At the time of the failure the last oil change (done by me) was 3400 miles and nearly 4 months. No prior leaks, drips, smells or warnings. Oil level had been normal at last check. Vehicle driven normally, no track use.
In my haste and failing to consider the oil filter as the cause I had the car towed to my dealership fearing catastrophic engine failure. (warranty concerns).
Dealership determined the failure was do to the oil filter gasket. Specifically - *The oil filter had lost its seal. *No evidence of drain plug failure. *No evidence of filter loosening. *Failure occurred ay the filter-to-housing interface. *Tech stated the gasket "did not seat properly.
How can a gasket fail after 3000 miles with no warning? I learned the hard way a marginally sealed flat gasket can survive for months and then fail instantly under the right conditions - especially a cold start. * oil is thick *relief valve may not open immediately *oil pump pressure spikes are highest *turbo engines amplify this due to oiling demands This is the exact moment a weak seal is most likely to fail.
Something I never really thought about and the real lesson learned - Gasket Design Matters
Molded / profiled design "P-style" or bead-style gasket. (As with OEM Honda Oil Filter Gasket)
Designed to:
*Self center
*Resist extrusion
*Tolerate minor surface or torque variance
*Pressure actually helps the gasket seal tighter
*Dynamic seal, not just a compressive washer
Aftermarket Flat Gasket (What Was on the Car)
*Simple flat rubber ring.
*Seal fine when new but can compress and "relax" over time.
*Are more vulnerable to cold-flow, compression set & extrusion under high pressure.
*Less margin for error.
Probable Failure Mode
Based on the evidence and failure pattern:
1. Gasket initially sealed well enough
2. Over Time normal heat cycles caused compression set
3. Clamp load reduced slightly (not due to loosening)
4. Cold start pressure spike caused gasket extrusion
5. Seal was instantly lost
6. Oil dumped rapidly
This could explain *No prior seepage *No warning signs & Sudden, total oil loss.
Damage considerations
I'm happy to report there are no signs of damage to the engine of turbo. Luckily within seconds of seeing the "Low Oil Pressure Warning" I was able to shut the engine down with seconds. Had I for whatever reason, chosen to go back into the house to let the car warm up we could be having a much different conversation and outcome.
Takeaways and Final Thoughts
*Gasket design matters
*A gasket can fail months later
*No leaks for 3000 miles does not guarantee long-term sealing integrity.
OEM filters aren't just about brand loyalty - the gasket geometry is engineered for the application .
This event has changed my view on oil filter selection. While flat gaskets can and do work, their margin is smaller. Does this mean that I will cease using the other 11 Pentius UXFL filters from the case I just bought? No, but you bet I will be laser-focused on proper tightening and seal integrity.
Hopefully this helps someone else avoid the same experience.
At the time of the failure the last oil change (done by me) was 3400 miles and nearly 4 months. No prior leaks, drips, smells or warnings. Oil level had been normal at last check. Vehicle driven normally, no track use.
In my haste and failing to consider the oil filter as the cause I had the car towed to my dealership fearing catastrophic engine failure. (warranty concerns).
Dealership determined the failure was do to the oil filter gasket. Specifically - *The oil filter had lost its seal. *No evidence of drain plug failure. *No evidence of filter loosening. *Failure occurred ay the filter-to-housing interface. *Tech stated the gasket "did not seat properly.
How can a gasket fail after 3000 miles with no warning? I learned the hard way a marginally sealed flat gasket can survive for months and then fail instantly under the right conditions - especially a cold start. * oil is thick *relief valve may not open immediately *oil pump pressure spikes are highest *turbo engines amplify this due to oiling demands This is the exact moment a weak seal is most likely to fail.
Something I never really thought about and the real lesson learned - Gasket Design Matters
Molded / profiled design "P-style" or bead-style gasket. (As with OEM Honda Oil Filter Gasket)
Designed to:
*Self center
*Resist extrusion
*Tolerate minor surface or torque variance
*Pressure actually helps the gasket seal tighter
*Dynamic seal, not just a compressive washer
Aftermarket Flat Gasket (What Was on the Car)
*Simple flat rubber ring.
*Seal fine when new but can compress and "relax" over time.
*Are more vulnerable to cold-flow, compression set & extrusion under high pressure.
*Less margin for error.
Probable Failure Mode
Based on the evidence and failure pattern:
1. Gasket initially sealed well enough
2. Over Time normal heat cycles caused compression set
3. Clamp load reduced slightly (not due to loosening)
4. Cold start pressure spike caused gasket extrusion
5. Seal was instantly lost
6. Oil dumped rapidly
This could explain *No prior seepage *No warning signs & Sudden, total oil loss.
Damage considerations
I'm happy to report there are no signs of damage to the engine of turbo. Luckily within seconds of seeing the "Low Oil Pressure Warning" I was able to shut the engine down with seconds. Had I for whatever reason, chosen to go back into the house to let the car warm up we could be having a much different conversation and outcome.
Takeaways and Final Thoughts
*Gasket design matters
*A gasket can fail months later
*No leaks for 3000 miles does not guarantee long-term sealing integrity.
OEM filters aren't just about brand loyalty - the gasket geometry is engineered for the application .
This event has changed my view on oil filter selection. While flat gaskets can and do work, their margin is smaller. Does this mean that I will cease using the other 11 Pentius UXFL filters from the case I just bought? No, but you bet I will be laser-focused on proper tightening and seal integrity.
Hopefully this helps someone else avoid the same experience.
Some good points. But IMO you’re giving OEM filters way too much credit. More have flat gaskets vs P style. Many are made by some of the worst offenders for QC. That said most of the made in Japan OEM filters have great QC but low efficiency. Anything OEM made by First Brands or M+H are a hard pass.
Love the failure analysis. Is it possible there was a "dry spot" on the gasket (where you didn't put oil on the gasket before installation) which caused it to bind to the mount and be twisted out of its groove during installation. Just enough to last...and then fail.
Not to mention, OEM filters are both flat or P design seemingly arbitrarily.
OEM Honda filters (even the FIltechs) are flat, but the S2000 filters are a P style design.
I think the real takeaway here is probably:
1) Lube the gasket
2) Use a wrench to ensure full seating, the contact+ X fraction of a turn rule.
I don't agree with the supposed attributes of P style vs flat. Either design can take a set, either can fail months later, both resist extrusion, both are self centering.
What does "dynamic seal" even mean here?
All elastomeric seals of this kind basically work the same. You have to constrain them fully in a gland so that the calibrated compression generates the sealing pressure you expect it to generate. The "P style when compressed is the same shape as the flat. It just has to compress the smaller contact area (the raised rib) to get there. This is because the mount flange is the last side of the gland and determines the final shape of the sealing cavity.
100% a cold start is absolutely going to tax the sealing of the lube filter and even the integrity of the can itself. Fleetguard burst tests oil filters to 750psi if I recall correctly because oil pressure on a cold start can spike MUCH higher than people think. The relief does indeed act, but often too slowly to shave the full peak. Typically the pressure spike is from the instant the system goes "hydraulically solid." You shut the engine off, oil flow into the oil system stops because it will still leak out through the normal flow passages and blow down.
When you start the engine again, the oil pump starts putting out flow into an oil system that has drained back to the pan mostly and may even have a little air in it. So at first the oil pushes air out (very briefly), but when that air is pushed out and system goes "solid" quite violently and has to now start pushing some cold thick oil through some very tight clearances.
THAT is the moment when oil pressure can spike high enough to blow out filters and even filter head mounts or oil coolers-- all before the pressure relief has the chance to act, because the pressure wave has to travel backwards through the system, through the filter (where it is damped) and so forth before it shows up at the pump outlet where the regulator is.
An anecdote about pressure spikes:
I was informed by one of our field service folks that a fuel filter on the supply system for a 95L V16 locomotive had failed, and it appeared to have ruptured from overpressure.
This is a Racor unit that we resold because Fleetguard didn't have a catalog part that worked. They sent me pictures. I pulled the PN and verified with Parker that this unit was rated to 200+ psi. SO how does it overpressure and rupture when it's on the suction side WAY upstream of the engine and just outside the belly fuel tank? This filter runs under suction (below atmospheric pressure) all the time!
When I realized what was happening and explained it to them, they were gobsmacked it was even possible, but measurement data confirmed what I suspected.
While the filter is far upstream, the key information is that a massive and sophisticated filtration system lie downstream. The system consisted primarily of steel housings and braided stainless hose, and it was downstream of a pump that kept it around 7 bar operating fuel pressure (~100psi roughly shop air pressure).
Now, you've pressurized two huge filters the size of scuba tanks to 100psi, pressurized a bunch of stiff plumbing to 100psi, run the engine and you decide now you need to shut it down.
What happens to the energy of that system when you shut it down? It dissipates. Quickly, and by the path of least resistance. So while the system took several seconds to build up pressure, it discharges that pressure in milliseconds. The result is that the same area under the curve is compressed in time, creating a very high peak.
It turns out such a peak was sufficient to travel back through the system, through the pump, and rupture a supply side filter at *shutdown*.
Essentially, the stuff plumbing and storage acted like a capacitor. It charged up, stored it, and then quickly and aggressively discharged that stored energy.
A special check valve had to be installed to arrest the backflow pressure spike at shutdown. That shutdown and "capacitor" dynamic is how filter rated to 200psi+ and operating on the suction side of the system ended up rupturing from an overpressure spike.
It turns out that it's a good idea to depressurize as slowly as you pressurize (also improves fatigue life of alloy components with no endurance limit). Ideally, we'd have had some kind of firmware to force the pump to "spin down" instead of just instantly stop, but that wasn't feasible on the required timeline.
I was informed by one of our field service folks that a fuel filter on the supply system for a 95L V16 locomotive had failed, and it appeared to have ruptured from overpressure.
This is a Racor unit that we resold because Fleetguard didn't have a catalog part that worked. They sent me pictures. I pulled the PN and verified with Parker that this unit was rated to 200+ psi. SO how does it overpressure and rupture when it's on the suction side WAY upstream of the engine and just outside the belly fuel tank? This filter runs under suction (below atmospheric pressure) all the time!
When I realized what was happening and explained it to them, they were gobsmacked it was even possible, but measurement data confirmed what I suspected.
While the filter is far upstream, the key information is that a massive and sophisticated filtration system lie downstream. The system consisted primarily of steel housings and braided stainless hose, and it was downstream of a pump that kept it around 7 bar operating fuel pressure (~100psi roughly shop air pressure).
Now, you've pressurized two huge filters the size of scuba tanks to 100psi, pressurized a bunch of stiff plumbing to 100psi, run the engine and you decide now you need to shut it down.
What happens to the energy of that system when you shut it down? It dissipates. Quickly, and by the path of least resistance. So while the system took several seconds to build up pressure, it discharges that pressure in milliseconds. The result is that the same area under the curve is compressed in time, creating a very high peak.
It turns out such a peak was sufficient to travel back through the system, through the pump, and rupture a supply side filter at *shutdown*.
Essentially, the stuff plumbing and storage acted like a capacitor. It charged up, stored it, and then quickly and aggressively discharged that stored energy.
A special check valve had to be installed to arrest the backflow pressure spike at shutdown. That shutdown and "capacitor" dynamic is how filter rated to 200psi+ and operating on the suction side of the system ended up rupturing from an overpressure spike.
It turns out that it's a good idea to depressurize as slowly as you pressurize (also improves fatigue life of alloy components with no endurance limit). Ideally, we'd have had some kind of firmware to force the pump to "spin down" instead of just instantly stop, but that wasn't feasible on the required timeline.
While 5W-30 should be fine in this application, even in Ohio. It's clear that a cold start pressure spike contributed to the problem, otherwise the oil would have puked during the last normal run, not on a cold start.
It's stuff like this that makes me question the "thickies" we have around here. Another recent thread had several of the members here recommending straight 40 weight in a Type R, even when the owner lived in an area where the temp is known to get down to 40F in the winter. Using thick oil on a cold start will surely blast open the pressure relief valve straight away, if the gasket doesn't blow first.
That said, it's likely that some issue with the filter contributed, or likely, is the root cause. I wouldn't be afraid of the filters, though. Tons of people using them, and this is the first time I've ever heard of a gasket failure. Maybe mark the filter next time, and make sure you get a full turn after gasket contact? That's what I'll do anyway, and I'm using those same filters.
It's stuff like this that makes me question the "thickies" we have around here. Another recent thread had several of the members here recommending straight 40 weight in a Type R, even when the owner lived in an area where the temp is known to get down to 40F in the winter. Using thick oil on a cold start will surely blast open the pressure relief valve straight away, if the gasket doesn't blow first.
That said, it's likely that some issue with the filter contributed, or likely, is the root cause. I wouldn't be afraid of the filters, though. Tons of people using them, and this is the first time I've ever heard of a gasket failure. Maybe mark the filter next time, and make sure you get a full turn after gasket contact? That's what I'll do anyway, and I'm using those same filters.
Yep, get into the habit of marking the dome of the filter with a Sharpie or a piece of tape once the gasket makes initial contact, then make sure it's turned 3/4+ turn after that. Use a proper filter end cap tool if required to get the proper turn amount.
Too add, as discussed in this thread about P-style gaskets, when those style of filters are installed correctly the base of the can is basically touching the filter seat, so there isn't an air gap for the P gasket to blow out of. If a filter with a flat gasket isn't tightened down enough, there is less compression of the seal, and there is a larger air gap for it to blow out of. This is why I always go by amount the filter turns after the base gasket first makes contact. If I can't get to 3/4+ turn by hand I have many filter end cap wenches to use with a ratchet to get the required tightness.
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Well, I was the primary culprit in the SAE 40 camp, a couple were amenable to my points.
The SAE 40 at 40F is not as thick as my 15w-40 at 20f, and no gasket blowing is occurring anywhere.
The pump is not in bypass. The low idle spec min is 10psi and the regulator on these doesn't open to closer to 80psi.
Also, this engine has piston oil squirters with integral ball check valves. They have a cracking pressure lower than the regulator. So if you get a pressure spike, the squirters open between 15 and 25 psi or so.
Effectively the K20C has secondary oil pressure relief via squirters even before the pump is in regulation.
I doubt the failure was related to compression set. Silicone is very resistant to compression set, especially when operated far below its temperature limit, and at relatively low squeeze (which was probably the case due to under-tightening).
The high oil pressure on the cold start was certainly a factor, not only due to the pressure on the seal, but also because the filter canister could start to deform from the pressure which would tend to increase the clearance gap. The PXL filters seem to be built like tanks though, so I doubt this would be a huge factor at <150 psi, but I don't know what aspects of the filter construction relate to this.
The performance of the seal changing over time was probably also a factor, but it's hard to say why. Silicone does thermally contract at low temperature much more than other elastomers, which would reduce the seal squeeze a bit. However, I believe low squeeze is only associated with leakage, not extrusion.
On the other hand, there are some factors that would seem to make a seal extrusion less likely to occur in this type of scenario. Elastomers tend to continue curing over time with exposure to high temperature, and this tends to increase their hardness. Lower temperatures will also increase the elastomer hardness.
Silicone retains most of its properties over a very wide temperature range though, and this probably applies to changes in hardness, so these factors might not help as much as they would with a nitrile rubber seal material. A seal material that get significantly harder in freezing temperatures would seem to be better at resisting seal extrusion in colder weather when oil pressure on cold starts will be higher.
I'd also expect the clearance gap to decrease slightly at low temperature as the filter and mounting surface thermally contract, which should also reduce the chance of extrusion.
You probably won't be able to get a full turn with a Pentius XL. I measured how much the gasket sticks out from the groove on a PLXL3593A, and it was only around 1.2 mm, whereas the thread pitch is 1.5 mm. That would mean the filter would bottom out at only 1.2/1.5 = 0.8 turns. My measurement was pretty rough, so this isn't very exact, but the gasket certainly sticks out by less than 1.5 mm.
When I installed a PLXL7317 on my Subaru, I could just barely turn it 3/4 of a turn by hand. I left it at that. My Subaru sees oil pressures well above 100 psi in cold weather and this filter is currently going though its second winter. So far so good.
Consider this: if your gasket protrudes 1mm above the face of the filter and the filter spud is M20x1.5, it will take 2/3 of a turn to compress the gasket as far as it can go. (1/1.5)
Think is was mentioned by someone before, that on a cold start-up the pressure spike could be much higher than what the oil pump's pressure regulator would normally control to. All it would take is a short, high pressure spike to dislodge a gasket on a filter that's not tight enough.
Also, when a filter can is hit with more pressure it can deform the can, but it can also lift the whole filter off the seat some distance depending on how beefy and still the base plate is. That can be seen in the Fram video where they show a filter being pressurized and the can will lift from the seat to the point where the base gasket blows out from the internal pressure. So in this case, the cold start pressure spike probably lifted the filter that probably wasn't quite tight enough to make the high internal pressure spike blow out the gasket. I'd recommend all oil filters to be at least 3/4 turn tight (which most install instructions show), unless specified otherwise, like for filters with a P-gasket. If it takes the appropriate tool to get 3/4+ turn then that's the way to go.
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The man is giving wrong advice, the recommendation isn’t to tighten to torque stop. It’s the same as it always has been.
And what has it always been?
