No announcement yet.

4M Oil Cooler Concern

  • Filter
  • Time
  • Show
Clear All
new posts

  • 4M Oil Cooler Concern


    so here is the low down on my biggest issue with my 4m..purchased my 68 crown back in October. Once getting it home I had to check to see if the motor was seized and if it was not see if I could get it to run on its own power.the motor turned out to turn over by hand so instantly dived into checking the fluids put in a good battery and clean the tank fired up with no issues..until my oil light came on the dash..
    immeditly I thought it could just be a faulty sending unit.. once buying a new one and trying it again it still got no oil pressue, I have tried removing the sending unit and turning it over and no oil was coming out..tried a mechanical gauge just incase and it was reading 0 psi.
    now I'm thinking its a oil pump.after searching fr months and paying crazy money for a new oil pump that is my next step.BUT! I also was thinking what if my oil cooler is blocked or has something obstructing the lines from the outlet tube out of the clock or the cooler or the inlet back into the pan?

    was just curious if anyone has had these issues? before I start pulling it apart to install a new pump

  • #2
    While not knowing the exact way the 4M cooler works, I suspect that the cooler is not your problem. Most coolers have some form of bypass.

    BEFORE you spend any money, get the engine out, on a stand, and disassemble it... the odds are the bearings being run with little or no oil they are likely in need of replacement. And the last thing you want to do is ruin more hard to find parts.......
    Cylinder head porting specialist -

    Information = POWER


    • #3
      I'm betting the oil pressure relief valve is stuck open. It's part of the pump assembly in the crankcase. The outlet of the pump goes to the filter first. You might try pulling the filter then cranking to see if anything is coming out.

      I didn't know that 4M's had coolers. My 2M doesn't. The 7M-GTE that scrapped had one, but it was a partial flow design. The cooler output just dumped back into the sump.


      • #4
        ya same kind of design, this ones has the outlet from the block below the filter and return back into the pan, but turned out that the drive gear on the oil pump was stripped and was not meshing with the shaft gear to make enough suction " oil pressure " but now I have another issue... it never ends lol


        • #5
          now it kind of sounds like something is hitting the pan? its not a rod knock but once fired up after the pump it ran nice and smooth, once it ran for 15min all of the sudden a clattery sounds has formed, I'm suspecting bad crappy rod bearings


          • #6
            Or corrosion inside got into an oil gallery and threw a bearing - all the M series oil pumps should fit bar the 7M from the supra I think, check with crowncustom on some thread here as he used one. Should become apparent if it's the pump or relief valve on inspection, and just blow some air through the cooler while it's off to double check.