Engine No Oil Pressure, Went Out On Highway

Discussion in 'Fox 5.0 Mustang Tech' started by 5point0stang88, Mar 6, 2014.

  1. I have a big problem. After I took the car for oil change, days after, my check engine oil light came on. I was thinking it was low so I took it back and they showed me where it leaked from the nylon tube out the sender.

    So I fix that, with new connection but same nylon to the mechanical gauge and it didn't leak but check light didn't switch off. Pressure remained good. At 2k normal engine temp, pressure was at a solid 45 psi. (25 psi at idle)

    Now on the highway, while driving I notice my oil pressure went to zero and stayed there till I exited highway. I can see no oil traveling through the tube. Oil level on dipstick remains good.

    What could my problem be, clogged oil pump screen, bad pump, bad oil sender unit?

    Also if pump, how hard would it be to change in the parking lot. I have jack and jack stands.

  2. Well, if you have a mechanical gauge, you don't have a sender.

    At first thought i'd think the engine is fine and it's something with the nylon tube. Could you have gotten tape in the tube or in the way? Compression fitting crush the tube?

    I've never had any luck with the nylon tube, switched to copper and never had an issue again.

    An engine with no oil pressure at all would knock and heat up.
    5point0stang88 likes this.
  3. Thanks for clarification, could that unit be bad anyway ? Im gonna change the tube with the new one that came with the kit. If that fixes I can upgrade later
  4. x2 on the copper tube. I've seen overtighted nylon tubes pinch off the oil pressure gauge or make it really slow acting. I would change it to copper first. If still not pressure reading pull the distributor and look to see that the oil pump shaft is ok.. Then you can use a priming tool and a drill to test the pump and see if it makes pressure without running your engine and doing any further damage if any.
  5. OK so I took the wire off the coil to prevent spark. And bump the engine twice for a few secs. The filter I had just put on minutes before attempting, was bone dry inside as well as no oil psi. Shouldn't the pump be pumping oil immediately? So I'm leaning toward dead oil pump or clogged screen.
  6. I bet the oil pump driveshaft is broken. There may be nothing wrong with the pump, or something got in the pump and seized it up which broke the oil pump driveshaft. If you pull the distributor you should be able to tell. If you have 1/4" drive long extension (about 10" long) and a 1/4" deep 1/4" drive socket, you can put the socket end on the oil pump driveshaft (if it is still there) and turn the shaft counter clockwise (preferable with a reversible drill) and see if the pump will work, or if it just spins freely. If the pump is working there will be a bit of a load on the drill. If no load, then the shaft is broken.
    5point0stang88 likes this.
  7. OK I need to invest in a drill again to do this. This sounds easier than the oil pump changing. Im getting towed home then will have to see about this.

    So i don't know about the oil driveshaft. Im guessing it turns the distributor ? and taking that out and turning it with a drill and extension in reverse?
  8. The cam turns the distributor, the distributor turns the oil pump shaft. Pull the distributor and see what's going on in there. It's going to be a broken shaft or oil pump in my opinion at this point.
    5point0stang88 likes this.
  9. Cool. Im just gonna replace with ARP shaft and go from there
  10. The stock oil pump shaft can twist up like a Twizzler and snap. Been there twice. If the pump shaft is fine and turns the pump OK, (and the gauge is OK), the next step is a spun bearing.
  11. Been there, done that and got a t-shirt with the oil pump shaft :doh:
    Mine snapped and was VERY loud when it did the exit stage right.
    Hardend shaft is now installed since but concerning a mechanical oil pressure gauge. I would only have an electrical one on a DD, way to many bad scenarios with broken lines or fittings that out way the destruction caused by a "failer scenario" on a much needed DD, .....IMO.
  12. Mechanical oil pressure gauge installation done the right way. This will prevent the problems you experienced..
    1.) Remove old pressure sender. It is located down by the oil filter and has 1 wire on a push on screw connector.
    2.) Install ¼” pipe tee fitting with a short ¼” nipple on the place where you removed the oil pressure sender.
    3.) Install the original oil pressure sender back in one of the tee ports.
    4.) Install the gauge line restrictor in the remaining port of the tee.
    5.) Connect the flex tubing or hydraulic hose to the gauge restrictor. Be sure to route the tubing or hose away from the exhaust manifolds. Be sure to either use regular hydraulic hose or stainless steel hydraulic hose for the pressure line. Do not use copper tubing for the connection to the gauge restrictor or engine. Over a period of time, the vibration will work harden the tubing and cause it to crack and fail.. Check the Yellow Pages or Google for a shop in your area that makes hydraulic hose assemblies.
    6.) If the gauge is going to mount under the hood, connect it to the end of the hose or tubing. Use some Tie-wraps to secure the gauge and its plumbing to the wiring harness on the driver’s side inner fender.
    7.) If the gauge is going to mount in the passenger compartment you get to find a place to run the tubing through the firewall. I suggest that you pick your spot from the inside since that is the area with the most difficult access. Do not run the tubing through the exact same hole as the steering shaft. It will tangle up with the steering shaft and cause major problems.
    8.) Install the gauge inside the car in the location of your choosing. Connect the pressure line to the gauge and secure it out of the way of moving parts with Tie-wraps.
    9.) Be sure to ground the gauge lighting wire to clean, shiny bare metal. Connect the other wire from the gauge lighting to a light blue/red wire on the radio wiring harness. There are 2 connectors in the radio wiring harness, but only one of them has the light blue/red wire you need for gauge illumination. Solder the gauge lighting wire to the light blue/red wire on the radio harness and cover the soldered joint with heat shrink.

    How to solder like a pro - Ford Fuel Injection » How To Solder Like a Pro a must read for any automotive wiring job.

    Be sure to use a gauge restrictor fitting in the pressure line going to the gauge. The restrictor will prevent all of the engine's oil supply from ending up on the pavement before you can stop it if the gauge line fails. I had a gauge line rupture, and the restrictor fitting saved my engine from serious damage.

    49295d1172975440-pressure-gauge-line-restrictor-pressure-gauge-flow-restrictor.gif [/b]
    #12 jrichker, Mar 14, 2014
    Last edited: Mar 14, 2014
    5point0stang88 likes this.
  13. Well I did the near impossible lol. It's not as hard as made out to be, but definitely no cake walk first time around.

    The original for pump locked up, and broke the shaft. Putting in the new parts tomorrow.
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    Sent from my SPH-L720 using Tapatalk
  14. once you put everything back together, and have everything buttoned up, you are going to want to keep a close eye, and ear, on this engine for any possible engine damage that you may have done driving the engine with no oil pressure. i would change the oil after about 50 miles and check for any increase in metal particles in the oil. i know its probably a bit of a waste, but i have had engines that lost oil pressure, that failed after being repaired, and usually with in 50-100 miles after the repair was done.
  15. I understand that and plan to put new oil back in, and good idea to change again. The motor sounded fine before I shut it off. I think what saved me was having over 3 quarts extra oil in the pan from thinking I was low as being told by the check oil light.
  16. When that happened to me I took the pan off and got it spotless before it when back on. Had good amount of trash in the bottom from that shaft breaking. Go Go Gadget hardened oil pump shaft :rlaugh:
  17. yes i understand you are going to put fresh oil in it, i wasnt questioning that. what i AM saying though is to change the oil again after about 50 miles of operation. that way you can check the oil and filter for any extra metal that might be getting into the system as a result of the no oil pressure issue. if the oil checks out after about 50 miles you are generally good to go, if not......
  18. Bet yes that's gonna be my plan, oil is real cheap insurance. :)
  19. :nice::nice:
    5point0stang88 likes this.
  20. Good luck, same thing happened to me last summer. It was knocking bad before I was able to get it off the road. I am shopping for a used long block now