Motorcraft Oil Filter Catastrophic Seam Failure
- Thread starter MaximumMini
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I may have missed it, but have you tried pushing down on the oil filter's bypass valve? If not yet, try it. Most open when the delta Pressure in the filter is around 14 psi. If there is unusual resistance to your finger pressure, the oil pump relief valve is now suspect.
If the oil pump pressure relief valve is working correctly, it will limit the maximum oil pressure to a safe level, regardless if the oil filter's bypass valve works properly or not. A filter could be clogged pretty good and the bypass valve not working right or be undersized for adequate bypass flow, and the oil pump should still regulate the max pressure to a safe level.
The filter seam blew out from either normal maximum oil pressure because it was defective, or the oil pump pressure regulator temporarily went hay-wire and over pressurized the system. Even if the filter's bypass valve opened normally with the pump going hay-wire, the pump could still over pressurize the filter and oiling system depending on the unregulated output flow volume of the pump. The filter bypass valve opening helps protect the filter media and center tube, but the oil pump can still over pressurize the filter can if the pump pressure relief valve malfunctions, even if the filter bypass valve is working correctly.
The filter seam blew out from either normal maximum oil pressure because it was defective, or the oil pump pressure regulator temporarily went hay-wire and over pressurized the system. Even if the filter's bypass valve opened normally with the pump going hay-wire, the pump could still over pressurize the filter and oiling system depending on the unregulated output flow volume of the pump. The filter bypass valve opening helps protect the filter media and center tube, but the oil pump can still over pressurize the filter can if the pump pressure relief valve malfunctions, even if the filter bypass valve is working correctly.
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Is the engines oil pressure relief valve after the oil filter pressure relief valve or are they in parallel so that both or either can divert the oil?
In other words, if I replaced the oil filter with a solid cap on the oil filter mount so that no oil could flow to where the oil filter normally would be, what would happen? It would just dump back into the sump via the pressure relief valve on the engine?
I think you answered this in the post above, just verifying.
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Ya know,
The end of the oil can where an oil filter removal tool would go......that looks swollen and disfigured. That took a LOT of pressure.
I'm thinking that fact means that the engines oil pressure relief valve caused this?
Either it temporarily got stuck as you said or it could still be stuck. If I raised the RPM's with the engine cold maybe it would pop the replacement Purolator Boss filter as well?
Once the oil is hot it thins out which is maybe why I can drive it once fully warmed up?
Put a case of oil, and a few filters in the vehicle, and drive in the right lane.
Or pull the oil pan and inspect.
Or pull the oil pan and inspect.
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I would not want to take a chance of 5 quarts of oil spraying onto a public road. This would put the lives of others at risk, not to mention being a massive liability.
Pulling the oil pan and checking the relief valve is the only option imo.
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Yes, as mentioned earlier in the thread, if there are other signs of over pressure then it was probably an oil pump over pressure situation. If the dome end of the can is also distorted then I would say the oil pump pressure regulation malfunctioned. Need to check the oil pressure when the oil is still pretty cold and the RPM is up pretty good. I'd think with cold oil it should be around 90-100 PSI maximum. Do you know what the max oil pressure should be if the pump is working correctly?
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I've done some calculations for the pressure drop caused by the end cap-canister gap in an oil filter. A 2 mm gap should be plenty large enough to limit the pressure drop to under 1 psi at high flow rates. A gap of less than 1 mm can start to become pretty restrictive.
It's hard to say if the gap was adequate on this filter since the canister is mangled.
The oil pump pressure relief is normally part of the oil pump itself, so it's before the oil filter and oiling system. It's meant to limit the outlet volume and pressure of the pump. It works independently of the oil filter bypass valve. The oil filter bypass valve only works based on the differential pressure (dP) across the filter. The filter bypass valve is there to: 1) ensure oil still gets to the engine if the dP is too high, and 2) ensure the filter media and center tube don't get damaged if the dP is too high.
I need to clarify that the center tube and media can become damaged if the bypass valve doesn't work correctly, and/or the bypass valve can't flow enough oil to limit the dP effectively if the filter is over whelmed with oil flow and resulting dP. Since the media and center tube in your filter looks OK, the bypass valve must have worked well enough to prevent media and center tube damage. But as mentioned earlier, the whole inside of the filter can still experience over pressure if the oil pump pressure relief valve malfunctioned. That situation could damage the can and blow out the seam, and not cause any damage to the media or center tube because the filter bypass valve worked well.
On a side note, racers use to disable the in-block filter bypass valve on GM engines ("racer mod"), and many would end up with a crushed oil filer center tube because there was no filter bypass valve to protect the center tube and media from excessive dP.
Ideally it would operate like that, but only if the oil pump pressure relief valve was able to handle all the output flow. But they aren't really designed to operate in that manner. They are designed to just shunt enough volume to regulate a maximum output pressure on an oiling system while feeding the oiling system a good amount of oil. Of course if you totally blocked off the flow to the engine (blocked the filter mount), the engine would blow-up due to zero oil getting to the oiling system.
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No. The only oil pressure test/reference in the Factory service Manual is that when hot, the oil pressure should be between 30 and 80psi at 3K rpm. My gauge only goes to 80psi
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Ok. I see. I would have to say the edge of the filter medium and holder has maybe 1mm clearance from the can.. It is tight.
Yeah, that spec isn't going to help much. Only thing you might glean from that is that 80 PSI might be what the pump should regulate the maximum pressure to since they say "30 to 80 PSI at 3K RPM". Most pumps will be in some level of pressure relief at 3K RPM.
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Hey, thanks for all your help. Really appreciate all the advice. So much you can learn from knowledgeable folks like yourself
I'll bet that Z06 of yours is a perfectly maintained jewel.
If it was my vehicle, at this point I would hook-up an accurate pressure gauge that goes up to 150 PSI or more to a main gallery after the pump if there is one in the block to tie into, and monitor the oil pressure in the garage with cold oil and some good RPM. Or might be easier to just get a new oil pump and put it in.
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What oil pressure did/do you see when the oil is hot and the revs are well over 3,000 RPM? If the pressure gauge is pegged at 80 PSI, it could still be well above 80 PSI.
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Good question. IIRC, when I tried it yesterday is was at 60psi.....but I'll have to do it again. I don't think it was pegged at 80psi.
For that matter, what is the normal burst pressure for an oil filter?
Normal oil pressure going down the highway (oil hot) is around 40psi...so would 140psi be about right?
Most oil filters are rated to take well over 200 PSI of internal pressure ... some more like around 250-300 PSI.
So if you saw 60 PSI with hot oil and well over 3,000 RPM, then that sounds pretty normal.
40 PSI at what RPM going down the highway.
I highly doubt it's going to be 140 PSI with hot oil (or even cold oil at higher RPM) unless the pressure relief valve is not working right.
