UPDATE: Oil Pump Whine When Cold - \\'04 Crown Vicky PROBLEM RESOLVED

10/19/13:

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Hello, I\\'m new to late model Crown Victorias, but not to cars or wrenching. I\\'ve been building, modifying, fixing and racing (mostly Mopars) for 30 years. Decided I wanted a P71 when they started flooding the market for reasonable $$$. This summer, I got a retired squad car for cheep which runs/rides/drives great. Makes a whining when cold since I picked it up (cold start, not necessarily cold day). Also makes the usual 4.6 rattling from the chain guides until the pressure kicks in. I was going on the whining being a tensioner/idler pulley or the p/s pump. Being as it\\'s hot and muggy as hell here in GA for most of the year, I put off messing with it until the other day. Put 3000 miles on it in the meanwhile with no problems. Long story short, it is not any of the above. I isolated the noise to the oil filter base/oil hose port housing with a stethoscope. I have to assume the noise is coming from the oil pump, or possibly the relief valve. Noise gets quiet after engine warm-up. Engine is filled with factory recommended 5W-20, although @ 100,000+ miles, I\\'m thinking of switching to 5W-30 or (OH MY GOSH!) 10W-30. My hopes that this engine was like a big block Chrysler, upon which the external pump can be swapped in about 5 minutes, were dashed when I read the 164-step process for R & R pump in the Service Manual. If I have to break down the entire motor just to swap the pump, I\\'ll just drive this one \\'till it explodes, then buy another P71. Any thoughts, similar experiences, or suggestions? Thanks!

10/19/13:

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I\\'m still tracking this problem down, but I believe there may be some sort of oil cooler bypass valve in the filter adapter. Can you verify or debunk this theory? I\\'m still studying on this possibility. It sounds like some sort of valve buzz. I\\'m thinking more and more that a pump issue would get worse/stay same with engine and oil temp increase. My noise goes away. Thanks.

11/3/13:

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I\\'m now convinced that the buzz/whine is coming from the cooler bypass valve. I removed and inspected it and its spring, and could find no obvious issue with it. I\\'m pretty sure it can be either shimmed tighter (or shut, which should allow full time cooler action), or simply left out which I would think would always allow a small amount of flow bypass the cooler. I am amazed that I can find absolutely NO information on the operation of this valve either on-line or in my factory service manuals (I even have a police/fleet training manual which mentions zilch about its function). My next step is to pick up a spare P71 filter base at the junkyard, so I can fiddle with it and investigate function. I don\\'t want to experiment on the car until I see what it\\'s designed to do. I\\'ll report back. Please advise, anyone, if you have additional experience, information or links to helpful info. RNOO

After weeks of theories and research and troubleshooting my problem is resolved. I experimented with removing, then blocking the oil cooler bypass valve, bypassing the oil cooler altogether (by making a U-shaped hose - not advisable to block ports on oil cooler equipped cars), etc. etc, all to no avail.

Hooked up diagnostic pressure gauge and taped to hood temporarily with racer tape, and big surprise, low oil pressure!!! Slow to come up upon cold start, then 40 PSI (with buzzing), dropping to 25PSI (buzz goes away) upon warm up, then 20 - 25 PSI @ highway speed, which is scary. Even scarier is, when you nail it, it goes to 20 PSI or less!!! I've probably punched it and made it sing to about 6000 RPM (guessing - no tach) about a dozen times in the 6 months I've had car, so it's a miracle it's all still together.

Today, I drained oil (again!) and saved it, since it now has $50 worth of Mobil 1 0W-30 in it, rinsed sump through drain hole with mineral spirits (clean as a pin inside, by the way), and ran 7mm camera up into pan. Was kind of difficult to see, but it appeared that pickup was contacting pan with no clearance whatsoever. No debris or sludge evident at all. I had noticed that pan had a VERY MINOR depression in it where it contacted something along the way, but hadn't really though much about that.

Since pan removal on the vehicle appears to require about the same man-hours as preparing the Space Shuttle for a re-launch used to take, I decided to attempt a fix through the drain hole. I polished an old screwdriver to remove sharp edges, and proceeded to use it to bend pan away from pickup as best I could, which did prove difficult. It is ugly, and I buggered up the drain hole threads a little (I'll see if it leaks when I check driveway tomorrow), but I managed to create some clearance, although not as much as I would have liked. Flushed sump with solvent again, and closed it up and refilled oil. Vehicle now has 70 PSI oil pressure @ cold startup and 40 PSI idling hot. Cruise oil pressure is now 60 PSI, but I didn't get it real hot. No buzzing from oil pump, either. PROBLEM RESOLVED.

As a footnote, I have to point out that the inferior Ford design that has the pickup opening completely at the bottom of the tube was the root cause of this failure (well, that and getting a small dent in the pan). This puts the oil system very prone to this type of failure, and I'd bet it has caused others problems as well. Many people probably just keep driving until the engine expires, and don't ever even realize what happened, since the crappy Ford oil pressure "gauge" is really just an idiot light in disguise. All of the Mopars I have worked on have pickups that are embossed with a U-shape in the bottom, and they are open slightly to the side. You can practically crush a Mopar pan without any oiling issues, unless you happen to bang it so bad that you tear a hole in it or crack the pickup tube. Just sayin'..........................

RNOO

Thanks for the update. A lot of people read these posts for info. I wish more people would post their results like you so we can learn from your experience...Dave

Dave,

If I can help just one other person with the same problem be able to rectify the situation before their motor is toast, I have done my job! In scanning the "blogosphere", I came across a lot of people with 4.6 equipped vehicles reporting similar issues. I'm sure they were the result of a handful of different causes, but I'd be willing to bet that a few suffered from the exact same problem that I was encountering.

As a further update, I took "the squad" on a 60 mile trip, weather was about 64 deg. Oil pressure stayed @ a constant 60 PSI at highway speed (55-65 MPH). Pressure is about 25 PSI @ idle with everything good and hot (or as hot as it's going to get on a 64 deg. day). This is with 0W-30 synthetic and a Motorcraft filter. Oil pressure @ start-up is instantaneous, and no more timing chain rattling for 5 - 10 seconds. I'm sure that there must be some bearing degradation, but with 25 idle PSI and 60 highway PSI, I have to assume it's not severe, and should probably live a long life now that it's getting oil. Heck, by opening up the clearances a little, I bet I picked up a few extra HP This thing does seem kinda hot for a 4.6 in a Crown Vicky with a 3.27:1 gear and all 4 cats installed and stiffling the flow of things.....

I'd also mention, If I had to do this repair again, I'd probably spot weld some temporary studs to the bottom of the pan and pull it away from the pickup that way. I'd would have been much easier and neater.

RNOO