Oil Pressure Question in reguards to filter and oil

Messages
5
Location
St.Louis
I've got a '97 Taurus SHO. 3.4L V8. At idle it's been running about 2psi. At 1500rpm's it runs up to 40 psi (in spec range). At idle I get the oil light flickering off and on. The oil pan was dropped and everything inside was clean with no sludge. The bearings and rods were good (making no noise). I've been using a mobil 1 filter, and mobil 1 5-30. It was recommended to me to switch filters to a different filter (motorcraft). Psi jumped to 9. I've also heard that mobil 1 5w-30 is a bit "thin" compared to other 5w-30's. I still get the oil pressure light occasionally. Any thoughts suggestions? Thanks, -Kevin
 
Messages
380
Location
Alabama
I'd get the oil sensor/sending unit checked out and replaced if needed, just to make sure that you are getting accurate readings.
 

MolaKule

Staff member
Messages
21,699
Location
Iowegia - USA
Did anyone check to see if the oil pump had loose clearances and was functioning properly? For any car over 100,000 miles, if I take the sump pan off, the oil pump gets checked and/or replaced. Was any of the main bearing caps removed to determine bearing wear? How about the cam bearings? All of these items can contribute to low oil pressure. [ April 01, 2003, 10:32 AM: Message edited by: MolaKule ]
 

Croaker

Thread starter
Messages
5
Location
St.Louis
The only way to take the oil pump off is to pull the engine. That right now is what I'm hoping to avoid. Oil pump is located is very hard to reach spot on the block, so out pops the engine. It is a V8 (although not a big one) in a front wheel drive car; there isn't a lot of room to reach anything. Thanks, -Kevin [ April 01, 2003, 10:45 AM: Message edited by: Croaker ]
 
Messages
1,527
Location
Southeast United States
Croaker, do you have both a pressure warning light and a gauge? Ford's oil pressure gauges are notoriously inaccurate on the later models. They are no more than an on/off switch that is triggered at about 7# psi. As was stated, I would first replace the oil pressure sending unit. If you still experience low pressure at idle, try going to a 10W-30. The fact that the pressure goes to 40# at 1500 rpm, means the engine bearings are probably still OK.
 

MolaKule

Staff member
Messages
21,699
Location
Iowegia - USA
You might want to run a cleaner through it, such as Neutra, Lube Control, or Auto-RX to free up the valve spring in the filter body, assuming that is the culprit.
 
Messages
1,565
Location
palm beach
usualy people i walk to with fords tell me the oil guages are not very good. same thing goes for the tempature guage. my dad was using his truck when the oil pressure dropped to zero, he immediatly shutdown and got towed home. he put an aftermatket guage from stewart-warner in, and found out he has good oil pressure. the guage in the dash broke.
 

Croaker

Thread starter
Messages
5
Location
St.Louis
No..GenIII SHO's ('96-'99) are V8's, Sending unit is good (replaced last year), a mechanical guage was hooked up to it. I'm not sure if it was with the sending hooked up or not (when the guage was run). The engine has 84,000 miles on it. The bearings and rods are all within' factory tolerances. I've heard it could be a valve spring on the pump itself. At a qoute of $400 just pull the engine and look at the pump is alot if nothing is wrong with the pump itself. I'm just tryin' to exhaust all other options before I start getting radical with it. I'm only a basic mechanic, and doing something like that I'll leave to someone who know's what's going on. -Kevin [ April 01, 2003, 03:59 PM: Message edited by: BOBISTHEOILGUY ]
 
Messages
149
Location
Carlsbad CA
The SHO oil pumps are extremely reliable, and with only 84K is most unlikely to be problematic. That said, anything is possible. Mine has 150K and has plenty of pressure; I have to almost kill it before the light will come on. Its becoming apparent the M1 filters (which I use) are dropping a lot of the pressure from the pump; it looks like if one has low pressure, a different filter is in order. In St. Louis, 10W30 M1 would probably be preferable. Mike
 
Messages
926
Location
Ohio
Hey, Hmmmmm, learn something everyday. I have a 98 Ranger with the 2.5L 4banger. The oil pressure guage immediately springs to the center position right after start up, so mine seems to be working ok. It's nice to know this. I'll keep an eye on mine. Thanks,,,,AR
 
Messages
13,132
Location
By Detroit
quote:
Originally posted by Airborne Ranger: Hey, Hmmmmm, learn something everyday. I have a 98 Ranger with the 2.5L 4banger. The oil pressure guage immediately springs to the center position right after start up, so mine seems to be working ok. It's nice to know this. I'll keep an eye on mine. Thanks,,,,AR
This actually is not a gauge, but a two way indicator. If pressure is above a certain threshold, the needle goes to the mid zone of the "gauge." If little or no pressure, the needle goes to low side. There is no in between. A real gauge should vary with increase in RPM from idle up to the mid RPM range area. Presumably the dummy gauge came about because of people complaining something must be wrong because their oil pressure was always fluctuating, not realizing it should.
 
Messages
308
Location
Houston, TX
(assuming it's not an "idiot gauge,") does it ever reach max pressure? if not, the oil pump bypass might be stuck open. doesn't help with your wanting to avoid engine removal, but that's kind of what it sounds like. did it happen all of a sudden, or did it slowly get worse with time? -michael
 
Messages
562
Location
Austin, TX
The SHO is a high volume design with an oil pump bypass valve kick in at 55psi (fairly low). From the link below: "The SHO V6 pump is rated at 12.1 GPM at 43 PSI at 6400." My guess is something like M1 Truck and SUV 5w40 would give good results. Regardless, you will see lowish pressure at hot idle. It is not designed for high pressure. This is an excellent site and discussion that I have used before: http://www.shoclub.com/lubrication-oil/lubrication-oilpart1.htm . [ September 13, 2004, 10:27 PM: Message edited by: Geoff ]
 
Messages
6,388
Location
Washington St.
Go back to an oil filter from the dealer. That is the filter designed for your engine. If that makes a positive difference, stick with it. If it makes no difference, you know the problem is elsewhere. I'd do the engine cleaning with Neutra, Auto-Rx, or Lube Control, then switch to a slightly heavier oil. I'd use 10W-30 in your summer and maybe 5W-30 in the winter. Stop by the Schaeffer factory at 102 Barton St. and pick up some Neutra and their oil. It is slightly heavier than Mobil 1, and I feel that it protects the engine as well or better. Ken
 
Messages
8,756
Location
RI
Use one of the 40wt oils or thick 30wt oils. Try the 0w40 Mobil1. Amsoil seems to thicken on its own. Try one of the 5w30 or 0w30 Amsoil oils. Don't use the boutique filters. You've seen the PSI raise with the switch from the Mobil1 to Motorcraft filters. But, where is the pressure sender located in reference to the pump/filter? Stick with the Motorcraft or its clones(purolator/proline). Check the idle or have it bumped up an extra 100rpm. Maybe even a simple tuneup can help. Anything that smooths out the idle should smooth out the oil pressure fluctuations. Plugs/filters/injector cleaner/decarbon.....other fluid flushes(like ATF/PS)..... Flush the coolant and toss in a new Ford thermostat(cooler engine=cooler oil=thicker oil).
 
Messages
3,858
Location
Cape Cod, MA
^^^what TallPaul said^^^ My 1990 E350 work van, my 1994 T-bird SC, and now my 2003 Marauder have all had fake oil pressure gauges. I don't think Ford has put a real gauge in any of their vehicles since at LEAST the late '80s, for the reason TallPaul states...
 
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