Problems with Oil pressure 1997 Ford Explorer?

We have a 1997 Ford Explorer V8 5L that seems to be having problems with the oil pressure.


We drive the vehicle for about 10 minutes and suddenly loose all oil pressure. Then one of two things happen, it will continue to have no oil pressure, which we stop turn the vehicle off and wait 10 minutes till oil pressure returns and repeat the process. Or the oil pressure will almost ';fight'; going up and down.


We recently did an oil change and changed the filter. So my question is, does this sound like a problem with the oil pump, the oil pan or one of the hoses?





ThanksProblems with Oil pressure 1997 Ford Explorer?
THAT SYMPTOM IS RELATED DIRECTLY TO A CLOGGED OIL PICK UP SUMP SCREEN.





A pluasable remedy would be to let motor get hot (let idle till hot), drain the oil, PUT THE PLUG BACK IN...


put 6 cans of fuel injector cleaner in the engine, let sit overnight... drain the chemical out of the engine, put in 4 qts of 10/30 motor oil and one can of injector cleaner back in and see if the treatment disolved enough of the gunk in your pan to clear your sump enough to maintain oil pressure during driving.





This occurance is most always associated with low quality oil, lack of oil changes and short trips.





Good luck, cause even if you do this treatment twice... it will be WAY cheaper than haviing your engine removed so they can take off your oil pan to clean itProblems with Oil pressure 1997 Ford Explorer?
There are many possible answers here, here is another to consider. It is possible the oil pressure sending switch is going bad. When you lose your oil pressure does the engine start making clattering noises. If not you still have pressure there. The pressure sending switch is a good place to start looking then, and it is less expensive than some of the other suggestions listed. Good luck with it.





ps In the 97 ford explorer the engine will automatically shut down if the oil pressure drops below 12.5 psi
Yep, Wizerdau likely is on to something. Put in a bottle of CD-2 lifter cleaner and run it a while and do another oil change. Include 8oz, (1/2 can) of SeaFoam with the next change.
sounds like the oil pump is going out
If you have high miles-


Low oil pressure is due to a combination of worn main and rod bearings and crankshaft journals. The oil pump itself does not create pressure. It produces flow and the resistance to that flow produces pressure. Resistance is created by the orifices in the engine block through which the oil flows, and the amount of clearance between the bearings and crankshaft journals. As the bearings wear, clearances increase allowing increased flow which reduces pressure.





Excessive clearances elsewhere in the engine can also reduce oil pressure. Wear in the lifter bores, excessive clearances between the camshaft journals and cam bearings, and excessive end play in the cam. Any cracks in the oil galleys, leaking galley plugs, or leakage between the oil pump and block will also reduce pressure.





Replacing the bearings or overhauling the engine to reduce the clearances. Installing a new oil pump or a higher pressure pump won't help because the bearings have too great a leakage rate to hold the required pressure. Installing a higher volume oil pump can increase flow and regain a little lost pressure. But the underlying clearance problem will still be there, which will accelerate bearing noise, wear and fatigue.





Another common cause of low oil pressure is wear or excessive clearances in the oil pump itself. Too much clearance inside the pump will reduce the pump's ability to pump oil efficiency, which reduces flow and pressure.





Restrictions in the pickup tube screen can choke off the flow of oil into the pump, reducing flow and pressure. Even a relatively small amount of varnish buildup on the screen can restrict oil flow at higher engine speeds.





The pressure relief valve, which may be located on the pump body or elsewhere on the engine, can be yet another cause of low oil pressure if the valve sticks open or is held open by a small piece of debris. The relief valve is designed to limit oil pressure as engine speed increases. The valve opens when pressure reaches a preset value (typically 40 to 60 psi). This vents oil back into the crankcase and limits maximum oil pressure in the engine. The reason for doing so is to prevent oil pressure from reaching dangerous levels. Too much oil pressure can be just as bad as too little because excessive pressure can rupture the oil filter or even blow out pressed-in oil galley plugs in the block.





Could be the result of air in the pump. If there is too little oil in the pan, air can be drawn into the pump. But this can also happen if the crankcase has been overfilled. The oil can become aerated (full of tiny bubbles) because it is making contact with the spinning crankshaft and is being churned into foam.





Sometimes the engine may become starved for oil at higher rpms because the oil is not returning quickly enough to the crankcase. The underlying cause here is usually severe varnish buildup that restricts the oil return holes in the head.





Leakage between the oil pickup tube and pump, as well as between the pump and block can also suck air into the pump. It is not unusual to find engines where the pickup tube has fallen completely off, causing a complete loss of oil pressure.





A plugged oil filter can be yet another cause of low oil pressure. When the oil leaves the pump, it passes through the filter before going on to the bearings and oil galleys. All filters create a certain amount of resistance to flow that increases with the rate of flow. But the amount is not much, typically only a couple of pounds. But as the filter becomes clogged with debris, the restriction created increases. Eventually the point may be reached where no oil will pass through the filter element. So to prevent such a blockage, a pressure relief valve located in the filter or where the filter mounts to the block is designed to open if the pressure differential across the filter exceeds a preset value (typically 5 to 40 psi). This allows the oil to bypass the filter and keep on flowing. But the engine's oil pressure will be reduced to that of the bypass valve. Replacing the plugged filter will solve the problem.





DIAGNOSING LOW OIL PRESSURE





A good place to start your diagnosis of a low oil pressure condition is at the dipstick. Check the oil level to see that it is at the proper level (not low and not overfilled). If low, the engine may be burning oil, leaking oil and/or be neglected. Adding oil may temporarily remedy the low oil pressure condition, but unless the oil level is properly maintained by your customer the problem may reoccur.





If the engine is leaking oil, recommend new gaskets or seals to fix the leak. If the engine is burning oil, the valve guides and seals are most likely worn, but the rings and cylinders might be bad, too. A wet compression test and/or leakdown test will tell you if the valve guides or rings and cylinders are worn. The least expensive fix in the case of worn guides would be to install new valve guide seals (if possible) without pulling the head. But the best fix would be to pull the heads and have the guides lined, knurled, replaced or reamed for oversized valve stems. Worn rings and cylinders would call for a complete overhaul.





Also note the condition of the oil and make sure it is the correct viscosity for the application. Heavier viscosity oils such as 20W-50, straight 30W and 40W may help maintain good oil pressure in hot weather, but are too thick for cold weather driving and may cause start-up lubrication problems especially in overhead cam engines. Light viscosity oils, on the other hand, such as straight 10W or 5W-20 may improve cold weather starting and lubrication, but may be too thin for hot weather driving to maintain good oil pressure. That is why most OEMs today recommend 5W-30 for year-round driving in modern engines.





If the oil level is okay, the next thing to check would probably the oil pressure sending unit. Disconnect the unit and check the warning lamp or gauge reading. If the warning light remains on with the sending unit disconnected, there is probably a short to ground in the warning lamp circuit. Likewise, if there is no change in a gauge reading the problem is in the instrumentation not the engine.





Bad oil pressure sending units are quite common, so many technicians will replace the unit without checking anything else to see if that cures the problem. This approach might save you some time, but it is risky because unless you measure oil pressure directly with a gauge attached to the engine you have no way of knowing if pressure is within specifications or not. Most warning lamps won't come on until oil pressure is dangerously low (less than 4 or 5 lbs.). So don't assume the absence of a warning lamp means oil pressure is okay, especially if the engine is making any valve or bearing noise.





If a check of oil pressure reveals unusually low readings, check the filter. It is possible the filter might be plugged with gunk. Ask the customer when he last had the oil and filter changed. Or, replace the filter and see if that makes a difference.





The next step would be to drop the oil pan and check the oil pump pickup screen. If the screen is clogged with debris, you have found the problem. Also, check to see that the pickup tube is properly mounted and positioned, firmly attached to the oil pump (no leaks) and is not obstructed.





If the oil pump is mounted inside the crankcase, the next step might be to remove and inspect the pump. Open the pump cover and measure clearances. Also, check for scoring or other damage. A broken pump drive would tell you something entered and jammed the pump. If the pump is worn or damaged, replacement is the only option.





If the pump appears to be okay, the next step would be to measure the rod and main bearing clearances. Check the clearances on the main bearing closest the pump (since this has the greatest effect on pressure), and clearances on the furthest rod bearing (since this will show the greatest wear). If the bearings are worn, they need to be replaced. But before you do so, carefully inspect and measure the crankshaft journals to check for wear, scoring, out-of-round and taper. If the journals need attention, the crank will also have to be reground or replaced.





Other checks might include camshaft end play, and/or pulling a valve cover or the intake manifold to check the cam bearings and lifters. Remember, excessive clearances or leaks anywhere in the engine's oil supply system can contribute to low oil pressure