Ok I have a 1997 Taurus Wagon with the 3.0 2v... if I remember that is the vulcan (or I could be wrong and it's the duratech but it doesn't feel nearly that strong...) Either way here's the deal.
I've had the car since monday when I bought it. 271,000 kilometers(about 168,000 miles) on the odometer. When I got her she was fairly quiet and vibration free but with that lag of sitting for a bit on a lot with dirty oil.
She was a little low on coolant too.
Topped up the coolant with a compatible premix. Did an oil change yesterday using a semi-synthetic high mileage formula oil.

Purred like a kitten and was much more willing to rev when asked (though I don't drive that hard there are some short onramps here in ottawa). Everything seemed ok up until yesterday. I took an onramp a little too quickly (sign said go 40 kph (25 mph) and I went in at 50 (32 mph) because I didn't brake enough. That shouldn't really be hard on the engine and she seemed fine save for a little body roll which I guess is normal. Now this ramp is a fairly long sweeper with very little banking so the lean was maybe about...8-10 seconds long and I accelerated out of it. The merge ramp is long there so I wasn't hard on the gas. Upon reaching the speed limit of 100 (62 mph). She settled in alright but then the oil light came on. I didn't notice any driveability issues and I was only going maybe ten kilometers. There was no detectable increase in noise or vibration and I wasn't blowing any smoke so I ran a little ways and got off at my exit, stopping at the first gas station.

Dip stick read full though the oil looked a little darker than it should... considering I had literally just changed it the day before.
I got back in and turned her over noting a slapping sound that I can only describe as somewhere between a clank and a flap (like metal against plastic). Oil light remains on... it was only 3 kilometers (about 2 miles) home at 40-50 kph (25-35 mph) so I decided to take her home where I could get her up on the ramps and get a better look.

We got home, the slapping sound not getting any louder and again no shudder or vibrations noticeable. I shut her down and we unpacked. Then I pulled out the ramps and set them up. Turned her over and the slapping sound was nearly twice as loud, it quite literally frightened me. On a whim though I put the car in gear. Slapping sound stopped. a few seconds of furrowed brow later, I put her in neutral, slapping sound return but not as badly. Back in drive slapping sound is subdued. At a complete loss for what's going on I gently drove her up the ramps to make sure I wasn't an idiot and put on the new oil filter too loosely or fogotten to put back the draining bolt (though I'm sure she would've warned me much sooner had I been that stupid... also I'd have notice the 4 liters of oil on my driveway >.&lt

Hop on my creeper and under the car I go. Bolt in place, clean. No leaks. Filter in place, Clean no leaks.
That's pretty much where I get confused.
So we turned over the car. Slapping noise. I get underneath and it's coming from the large black plastic whatever that is behind the filter but beside the oil pan, which I'm guessing is my oil pump. Have trustable friend step firmly on brakes and shift into gear, slapping noise significantly reduced but not gone, just easier to hear from under the car. For the life of me I can decide how an oil pump that was fine with oil thicker than mud was fine but with new clean tasty oil can no longer pressurize...

So I doulbe checked that everything was good and we backed her off the ramps. Figure, let her sit, see if she's burnt off her oil and the dip stick was just reading wrong. Come back a little later. Dip stick still reads full. Oil is darker still than before... almost to the point where I'd consider another oil change in the next 500-1000 kilometers...under normal conditions...The oil is two days old. It shouldn't be so dirty. And I DID install a brand new filter too... I don't understand... unless somehow grit in the motor is coming loose and clogging up the pump... I don't know how badly the car was treated before... I was told the standard thing that every used dealership says which is that the car was lady driven on the highway for the last X amount of years :P

I had to drive it today to get my boyfriend to work. We took the backroads which have limits no higher than 80 kph (50 mph) and I babied her so she'd shift into each gear, on the way up, at or below 2,000 rpm. I can hear the slap under load now but it's still much quiter than when free idling in neutral or park. I guess I can pick it out because I know what to listen for. There's also a skittery sound almost like a CD skipping loudly coming from around where the intake meets the head. I'm guessing this is the beginning of protest from my barely or completely unlubricated lifters and valves. I remember this sound from a previous hyundai accent. The mechanic said that car had a lazy lifter issue. In this case I'm assuming it's not so much laziness as lack of lubrication due to low pressure.

I didn't pay a lot for this car but the one thing that was in great shape was the motor. I want to keep it that way. There's a lot of life left in this little vulcan and up until I changed the oil she was strong and sturdy.

Is my oil pump dead? Did I kill it or maybe it's just standard for something like that to just die after 10 years? I've heard that if you take too steep a hill or a corner to quickly that you can starve an oil pump causing it damage... Is that what happened?
I can afford the parts but not the labour so whatever the solution is I'll likely be doing the work myself... I just need some help diagnosing this. I'm sure once I get the oil pressure back up those lifters will quiet right back down and all will be right.

Other notes about the whole situation:
Right before the transmission shifts from one gear to another and the clutch slips in the slap becomes audible like it's in neutral... for that moment of shifting I can feel the slaps in the gas pedal.
The slap also occurs while decelerating (again when the engine clutches out for the shift) but cannot be felt through the brake pedal.
While idling, if you place your hand on the plastic cover that protects the throtle body (where the line attaches from the gas pedal) the plastic housing shakes in time with the slaps as the gas pedal does when shifting...
Oil is progressively becoming dirtier and dirtier but is not contaminated with coolant.
Coolant is not contaminated with oil.
Coolant is clean.
There are no oil leaks detectable on the driveway or from under the car.
The oil level reads full and the engine is not burning the oil nor is it smoking from the tail pipe.

Help me save my comfy wagon, I was looking forward to august camping trips.

 

Ok so we checked last night and it's either a blown oil pump or a dead intermediate shaft...
or in a worst case my cam could be on the way out.
Used the Haynes manual to Identify the motor. It is the OHV unit.
Anyway taking off the oil pan to get to the oil pump ...in just a few minutes actually.
Started her this morning. No oil light. No slap no sticky valve sound... hmmm.
Drove the 20 feet from my friends driveway into her garage. Reaching the garage oil light returns... after a moment of gently bringing her up the ramps the slapping very quietly begins as lubrication breaks down. Shut her down since I don't need to move her again for a while.
I don't like that this can come and go but I'm getting to the bottom of it shortly... from underneath her.
More updates as I continue.

 

i have the same car, it dont like synthetic or blend syntethic oil at all. might want to drain her out and put in regular nice 20-50 castrol. if that dont help i think you got a bad cam. not a great thing to fix. there are updates to weld the cams so it doint happen again. your local good mechanic can advise. try the oil. if your pump were bad you never would have made it home . seek out hayapower on this site he is all knowing and will know at once whats wrong.

 

Ok well... I got her up... Drained the oil and got a better look at the oil pan than before... Then dragged out the Haynes manual.
Seems I need to take off the starter motor and the Y pipe for the exhaust before I can do the oil pan so I guess it will have to wait for tommorrow.
I have bought a new non-synthetic 5-30 oil and another oil filter to replace the brand new oil and brand new oil filter I JUST put on >.<
However I'm loathe to just start dumping new oil changes into the car every two days so before I fill her back up I want to take her apart. So I'll get to that tommorrow. More when I have her all apart.

 

K so my socket set sucks and broke off whie I was trying to remove the starter. So i put the fresh oil in and drove to canadian tire to return the socket set >.<
no oil light no slap no noise at all.
until I got to canadian tire. Oil light on... slap returns...
I added a little more oil when I got there (half quart) and the oil light went out briefly but came on again this time much faster. the slap is persistent and the engine is sluggish now...
unless I shut her down. Upon turning over after resting for a minute or two I have full oil pressure.
What on earth would cause slow oil pressure loss without burning or leaking out any oil?
My mechanic can't look at the car today but advised that it could be a bad bearing... the cost of which is high enough to justify simply buying another car of the same type.
PRoblem is... aside from this wonky engine... Everything else works so I'm reluctant to part with it...
Cruise, power everything, all electrical components, the underneath has no rust... and only minor surface rust on the rear hatch.
It needs new tie rods and ball joints (what taurus doesn't once a year?) but other than that... there isn't anything wrong...
Maybe I should just look for a cheap junker who rusted out but still has a good body and get that engine put in instead?
or is this worth fixing?