Oil Check Valve/Oil Pressure Warning Light

Old Fogey UK
Old Fogey UK Expert Adviser

Further to my post earlier today, I've taken the oil check valve off, disassembled it and cleaned the sludge out.

Everything inside looked OK but the oil warning light is still staying on when I start up.

Could the problem be related to the wiring or do I need to take the oil pump off and have a look inside that also ?

Obviously, I'm loathe to run the motor until I'm absolutely sure it's not an oil pump/flow problem.

Comments

  • Geoff
    Geoff Senior Contributor
    Disconnect the input to the pressure switch, and start the motor.  the oil should pulse out.  If not the problem is in the pump or pipes.  
  • bob ward
    bob ward Senior Contributor
    If the oil light wire is shorting before it gets to the oil pump that will give you a permanently on oil light. If your car still has the original wring that is a distinct possibility.
  • Old Fogey UK
    Old Fogey UK Expert Adviser
    Thank you both very much.
     I will follow up your advice.
  • Old Fogey UK
    Old Fogey UK Expert Adviser
    The oil pump is working. So it must be a short. I can't see an obvious wiring problem, so it's going to be a call to my local car electrician - who, fortunately, is a classic car owner himself.
    In the meantime, I'm assuming it's safe to use the car.
  • 5433HET
    5433HET Expert Adviser
    Can you use a test light? I had to replace a bad sender.
  • Geoff
    Geoff Senior Contributor
    Disconnect the wire from the sender.  If the light is still on, the fault is in the wiring, if it goes off, then  it is the sender. 
  • Old Fogey UK
    Old Fogey UK Expert Adviser
    Geoff said:
    Disconnect the wire from the sender.  If the light is still on, the fault is in the wiring, if it goes off, then  it is the sender. 
    Thank you - I'm going into the garage right now to check that, Geoff.
    If it is the sender, they're available from the ROC.
  • Old Fogey UK
    Old Fogey UK Expert Adviser
    I disconnected the sender and turned the ignition on and the oil light came on but the generator light didn't.
    Reconnected the sender wire and turned the ignition on - both lights came on.
    Wiring problem ???
  • Geoff
    Geoff Senior Contributor
    That is weird!   The ignition switch terminal goes to both the oil and generator lights.  What happens when you disconnect the  generator light wire from the relay?   Whatever, yes, you definitely have a wiring problem!
  • Old Fogey UK
    Old Fogey UK Expert Adviser
    I'm calling the auto electrician this morning !
  • Geoff
    Geoff Senior Contributor
    Do you have a wiring diagram?   I can scan and send if you need one. 
  • bob ward
    bob ward Senior Contributor
    edited September 2020
    Minor diversion, looking at the 34 H&T and 35 T Special wiring diagrams I have it looks like the coil is part of the ignition lock. Am I understanding that correctly?
  • Old Fogey UK
    Old Fogey UK Expert Adviser
    Thank you all very much for your advice but, at the end of the day, I'm a simple-minded lawyer and a barely competent car restorer and the mysteries of car electrics are way above my pay grade.
    I'm leaving this one to my local car electrician who is a classic car owner himself !
  • Old Fogey UK
    Old Fogey UK Expert Adviser
    When he's fixed it, I'll let you know what the problem was but, if past experience is anything to go by, it will have been something I did wrong !
  • Old Fogey UK
    Old Fogey UK Expert Adviser
    The electrician is coming next Tuesday.