Announcement

Collapse
No announcement yet.

Strange water temp readings after track day

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

  • Strange water temp readings after track day

    On my way home from a track day, my water temps were extremely low. Normally the car sits at 180 when driving. It almost never deviates from that temp unless I am doing autocross or a track day. On my way home the temps were sitting around 150. I checked the coolant level when I got home and it wasn't significantly low.

    During the track day the temps were cooler than before topping out at about 212. This is improved over previous years where it would be creeping above 225. My mid mount IC is helping get more air to the radiator over my old front mount.

    I haven't had much time to troubleshoot it yet. Any ideas? Do you think the thermostat could have failed and caused this?
    Chicago Region SCCA SM # 688 http://www.scca-chicago.com
    TSSCC SM # 688 http://www.tsscc.org

  • #2
    I haven't had time to trouble shoot the increase in efficiency my cooling system is seeing...lol sad story bro


    really though sounds like a stuck open thermostat, assuming your temp sender is on the outlet from the head.

    it's either that or the sender is fubar'd but it would be the first i haveheard of such an issue.
    I am SKULLWORKS

    Comment


    • #3
      I was concerned that the lower readings were due to a stuck closed thermostat so no cold water/coolant was getting to the engine. I really need to install that oil temp gauge I have sitting in the garage.

      My temp sender is in the upper radiator hose. I still have the stock temp gauge and that was showing much lower than usual as well.
      Chicago Region SCCA SM # 688 http://www.scca-chicago.com
      TSSCC SM # 688 http://www.tsscc.org

      Comment


      • #4
        Had some time to go trouble shoot. I noticed my fans are turning on full blast way early. I've had 2 fan controllers go out but none like this. I also felt the radiator near the upper radiator hose and it was getting hot pretty quick while the other side was cool. That led me to believe that the thermostat could be stuck open like tower suggested. Normally it takes a bit to heat up because the thermostat isn't letting coolant into the engine yet. That might also explain why the fans came on early, if the radiator is getting hot quicker. I have the fan controller temp sender right under the upper radiator inlet.

        You think there is any harm in leaving it that way for a bit? I only drive it to and from track events and the extra cooling couldn't hurt. Is it bad for the coolant temp to be around 150 for leisurely driving?
        Chicago Region SCCA SM # 688 http://www.scca-chicago.com
        TSSCC SM # 688 http://www.tsscc.org

        Comment


        • #5
          Originally posted by eye-5 View Post
          Normally it takes a bit to heat up because the thermostat isn't letting coolant into the engine yet.
          Thermo's stuck open usually do the opposite. The engine take more time to heat up. And when it works properly, you reach working temp in a minute or two at around 22C outdoor temp.

          Originally posted by eye-5 View Post
          You think there is any harm in leaving it that way for a bit? I only drive it to and from track events and the extra cooling couldn't hurt. Is it bad for the coolant temp to be around 150 for leisurely driving?
          Well, it will have an effect. Positive or negative, don't know really. You won't have an efficient heater that is for sure :P.

          I know its a pain in the ass with the 4L of prestone and the bleeding. but the freaking thermo is 10$... why not just change it. Maybe drill a hole or two at the top to help bleeding in the same time.

          p.s. I just remembered, on the normal tune, under 80C the computer compensates with fuel(for evaporation purposes) so your mixture will get richer.

          My Blog

          My Racing video's

          Comment


          • #6
            My SR20DET with Nismo thermostat, aluminium radiator and standard clutch fan sits at 67C/153F almost always on the road, on the weekend racing 4 lap sprints in 10C/50F air temps it only reached 71C/160F. The only time I've been above 80C/176F is when I've accidentally left my air con on during sprints on a hot day (reached 100C/212F once). I've also been concerned that always running so cold would be bad for my engine.

            Comment


            • #7
              Cylinder/Piston clearances and ring gap recommendations are based on normal engine running temperatures. Aluminum and Iron expand at different rates so the gaps won't be the same at lower temperatures. It would take me a while to find it but I've run across engine wear studies on the subject and wear increases significantly below 180f. It's a long term thing so it won't hurt to run like that until you get a chance to fix it but I wouldn't leave it like that. I haven't checked the references on this site but the graph is similar to others I've seen;
              http://www.carnut.com/ramblin/cool3.html
              Don Johnson (really!)
              Just so you know.

              Comment


              • #8
                Thanks DJ Silver, that is what I was looking for.

                Workinprogress, It wasn't about the time or money in changing another thermostat (I think that's 4 now). It was just about how hard I've worked to get the water temps down and now they are way down. Figured it would be nice to not have to worry about it on track days.
                Chicago Region SCCA SM # 688 http://www.scca-chicago.com
                TSSCC SM # 688 http://www.tsscc.org

                Comment


                • #9
                  Like what has been said, symptoms of a stuck closed thermostat are overheating and top hose hot/lower hose cold. It's possible that the thermostat is stuck open, how long does it take for the car to warm up?

                  I had a 3 hour drive home from the track over the weekend, I noticed that if I drove through shade for long enough my temps would drop about 5 degrees, and a small rain shower dropped temps 15 degrees. Was it any cooler out when you were driving home from the track?

                  Slightly unrelated: at what temps do you pull off track? I had a few coolant leaks on Saturday, I would pull off when temps got over 200. I never really got to hot lap it after I fixed all of the issues so I'm not sure where the temps would finally settle, but I'd like to know what the highest "safe" track temp is.

                  Comment


                  • #10
                    200* is right where Most cars are designed to run in "normal conditions". I'd say 235* would be where I would pull off track. If I pulled off at 200*, I'd have to exit after my warm up lap. Normal driving I am almost always right at 180* regardless of outside temp after the car is warmed up.
                    Chicago Region SCCA SM # 688 http://www.scca-chicago.com
                    TSSCC SM # 688 http://www.tsscc.org

                    Comment


                    • #11
                      UPDATE. I figured I'd fill everyone in on what it was. Open thermostat, like most of you said.

                      There was a tiny piece of plastic preventing the thermostat from closing all the way. It was from when I hit a cone and took out the drain peacock thingy on the radiator. I drilled the remaining pieces out and flushed it, thought I got it all.

                      At anyrate, there is a Nismo one in there now along with silicone radiator hoses.
                      Chicago Region SCCA SM # 688 http://www.scca-chicago.com
                      TSSCC SM # 688 http://www.tsscc.org

                      Comment


                      • #12
                        Haha never heard of that happening, good thing you figured it out though.

                        Since it's kind of on topic, at what oil temps do people take a cool down lap? I was at an event last weekend, ambient temps on track were around 105. Coolant never got over 190, oil temp got up to 200 though. It's still pretty low, but towards the end of the day it started heat soaking and temps were going up. Not sure at what point I should pull off track to cool things down.

                        Comment


                        • #13
                          Every car will be slightly different on running temps, and you need to drive your car on track long enough for them to build up to steady-state conditions. My car runs about 210 water temps on hot days (it gets to 105 here during summer..), 200 when the weather is more tolerable.
                          If the temp is slowly building as you pick up speed and run thexar harder, and you're not worried about leaks, then I wouldn't worry until your water is at 225, and oil can run up to 250. Vettes halve huge issues with high oil temps, and I've seen them running at 300+ all day long at the track with no problems. Just change the oil afterwards and move on with life.
                          Originally posted by SoSideways
                          I don't care what color they are as long as they are LONG AND HARD.
                          '04 G35 Sedan 6MT- The DD
                          '96 240SX- The Track Toy

                          Comment


                          • #14
                            Oil temps will be high on a wet sump motor depending on how good the oil cooler is working. I use to race dirt track and oil temps would run 280-350 depending on air temps. Yes with high oil temps you better run good oil. now with that said we put a griffin radiator with oil cooler and temps would run about 20 degrees hotter than water. On our dry sump motors 10 degrees difference. If any more than that, you better take the motor apart and see whats wrong.

                            Comment

                            Working...
                            X