Announcement

Collapse
No announcement yet.

Red engine light

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

    #16
    91, I am guess from your answer to Lincolnmania that the light does not go off if the engine rpms are increased?
    03 Marauder DPB, HS, 6disk, Organizer Mods> LED's in & Out, M&Z rear control arms, Oil deflector, U-Haul Trans Pan, Blue Fuzzy Dice
    02 SL500 Silver Arrow
    08 TC Signature Limited, HID's Mods>235/55-17 Z rated BFG G-Force Comp-2 A/S Plus, Addco 1" rear Sway, Posi Carrier, Compustar Remote Start, floor liners, trunk organizer, Two part Sun Visors, B&M Trans drain Plug, Winter=05 Mustang GT rims, Nokian Hakkapeliitta R-2 235/55-17
    12 Escape Limited V6 AWD, 225/65R17 Vredestein Quatrac Pro, Winter 235/70-16 Conti Viking Contact7 Mods>Beamtech LED headlight bulbs, Husky floor liners

    Comment


      #17
      As mentioned above for the most part:

      The red engine light in a Ford (Mercury has two lights, Ford has one) represents either a low oil pressure, or high temperature, or both condition.
      The lights receive 12V at the gauge cluster, and the lights are turned on by the switches (like a "sender" but it is only on or off) grounding the wire.

      Oil pressure switch grounds the wire when oil pressure is below a certain pressure, from memory it's about 6psi. Therefore, the light is normally lit solid any time the key is on but engine is not running, and then turns off once the engine is running. As noted above, when an engine is worn, low oil pressure at idle that goes higher when you rev it is sort of normal (not good, but common as things get worn out).

      Temperature switch grounds the wire when temperature is above a certain amount, from memory it's about 260 degrees Fahrenheit.

      Reasons why the light can turn on:
      1. The oil pressure is low.
      2. The temperature is high.
      3. One of the switches is broken.
      4. One of the switches was mistakenly replaced with a sender. In parts store catalogs usually a switch is described as "with light" or "without gauge", and a sender is described as "with gauge".
      5. One of the switches is defective.
      6. A wiring fault is allowing the bare metal of one of the wires (oil or temp) to touch bare metal somewhere, which grounds the wire turning the light on.

      Sounds like #5 or #6 is your likely option.

      The computer has a temperature input, but it uses a completely separate sender. There is no interconnection between the red engine light in the cluster and the computer. They do not know that each other exist at all.

      A very hot engine will run sluggishly, but it is also possible you have an unrelated issue if wiggling the wire makes the light come on or off.
      Last edited by kishy; 08-12-2022, 10:14 AM.

      Current driver: Ranger
      Panthers: 83 GM 2dr | 84 TC | 85 CS
      | 88 TC | 91 GM
      Not Panthers: 85 Ranger | Ranger trailer | 91 Acclaim | 05 Focus
      Gone: 97 CV | 83 TC | 04 Focus | 86 GM
      | Junkyards

      Comment


        #18
        I think the bare spot in the wire to the coolant temp was touching the alternator bracket and grounding out

        Comment


          #19
          Originally posted by kishy View Post

          The red engine light in a Ford (Mercury has two lights, Ford has one) represents either a low oil pressure, or high temperature, or both condition.
          The lights receive 12V at the gauge cluster, and the lights are turned on by the switches (like a "sender" but it is only on or off) grounding the wire.
          I’d just like to point out the Mercury clusters when equipped with all the warning lights and the check level oil sensor will only feature the single red engine light. The base clusters without the extra lights or when not equipped with the check level lamp will feature the split temp/oil warning lights.


          My Cars:
          -1964 Comet 202 (116K Miles) - Long Term Project
          -1986 Dodge D-150 Royale SE (112K Miles) - Slowly Getting Put Back Together
          -1987 Grand Marquis Colony Park LS (325K Miles) - April 2017 + September 2019 POTM Winner
          -1997 Grand Marquis LS (240K Miles) - The Daily Workhorse & March 2015 + January 2019 POTM Winner

          Comment


            #20
            that's exactly what happened, the little clip on plug for the coolant temperature rotated and the bare wire was touching the coil bracket

            Comment


              #21
              As an aside, why does the engine get sluggish when too hot? Are metal parts expanding with heat and rubbing against each other?
              1987 Lincoln Town Car - Signature, "Prudence"

              Comment


                #22
                intake air gets really hot and it can't burn enough fuel to get any power. The intake will be dang near as hot so the intake air temp goes up as well.

                Only two things are infinite, the universe and human stupidity, and I'm not sure about the former. -- Albert Einstein
                rides: 93 Crown Vic LX (The Red Velvet Cake), 2000 Crown Vic base model (Sandy), 2003 Expedition (the vacation beast)
                Originally posted by gadget73
                ... and it should all work like magic and unicorns and stuff.
                Originally posted by dmccaig
                Overhead, some poor bastards are flying in airplanes.

                Comment


                  #23
                  Well, it happened again on the way back from work, coolant sensor wire wasn't touching anything but the light went off when I pulled over and unplugged the wire and plugged it back in while the engine was running. What do you guys think? Coolant isn't boiling over or anything and it was running just fine this time
                  Last edited by 91merc; 08-12-2022, 02:39 PM.

                  Comment


                    #24
                    Have a non-contact thermometer? Or even a contact thermometer for that matter?
                    03 Marauder DPB, HS, 6disk, Organizer Mods> LED's in & Out, M&Z rear control arms, Oil deflector, U-Haul Trans Pan, Blue Fuzzy Dice
                    02 SL500 Silver Arrow
                    08 TC Signature Limited, HID's Mods>235/55-17 Z rated BFG G-Force Comp-2 A/S Plus, Addco 1" rear Sway, Posi Carrier, Compustar Remote Start, floor liners, trunk organizer, Two part Sun Visors, B&M Trans drain Plug, Winter=05 Mustang GT rims, Nokian Hakkapeliitta R-2 235/55-17
                    12 Escape Limited V6 AWD, 225/65R17 Vredestein Quatrac Pro, Winter 235/70-16 Conti Viking Contact7 Mods>Beamtech LED headlight bulbs, Husky floor liners

                    Comment


                      #25
                      Our non contact one broke a while back unfortunately, but I put some liquid electrical tape on the bare wire and wire brushed the crusty post on the sensor and its not done it since

                      Comment


                        #26
                        Originally posted by jaywish View Post
                        91, I am guess from your answer to Lincolnmania that the light does not go off if the engine rpms are increased?
                        Correct

                        Comment


                          #27
                          Well it happened again so i think it's just the sensor, isn't getting hot or steaming or running rough

                          Funny enough, I don't remember that light coming on the time I actually was overheating

                          Comment


                            #28
                            check the oil pressure with a real gauge, check the temperature with a real gauge. Its the only way to know for sure. Fair guess if it had no oil pressure or was massively overheated you'd know but having warning lights on just freaks me out too much to ignore it.
                            86 Lincoln Town Car (Galactica).
                            5.0 HO, CompCams XE258,Scorpion 1.72 roller rockers, 3.55 K code rear, tow package, BHPerformance ported E7 heads, Tmoss Explorer intake, 65mm throttle body, Hedman 1 5/8" headers, 2.5" dual exhaust, ASP underdrive pulley

                            91 Lincoln Mark VII LSC grandpa spec white and cranberry

                            1984 Lincoln Continental TurboDiesel - rolls coal

                            Originally posted by phayzer5
                            I drive a Lincoln. I can't be bothered to shift like the peasants and rabble rousers

                            Comment


                              #29
                              I bought a set of gauges for the car, just haven't had enough time off work to install them

                              I don't think it's oil pressure because the light goes off when I unplug the coolant sensor


                              Could rust in the cooling system somehow be messing with things?
                              Last edited by 91merc; 08-13-2022, 06:07 PM.

                              Comment


                                #30
                                The corrosion you've talked about on the sensor contacts could be masking a shorted sensor. There may also be corrosion inside the plug harness causing issues. Might be worth replacing that sensor as they're relatively inexpensive. Might also be a good idea to check further up the wires to make sure there's not more broken insulation making contact in other locations.

                                Only two things are infinite, the universe and human stupidity, and I'm not sure about the former. -- Albert Einstein
                                rides: 93 Crown Vic LX (The Red Velvet Cake), 2000 Crown Vic base model (Sandy), 2003 Expedition (the vacation beast)
                                Originally posted by gadget73
                                ... and it should all work like magic and unicorns and stuff.
                                Originally posted by dmccaig
                                Overhead, some poor bastards are flying in airplanes.

                                Comment

                                Working...
                                X