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  • Having overheating issues. Any ideas?

    Hello all.

    Until recently, I have been prepping the S14 for trackdays. One day on the way home from Summit Point, it was about 75 F outside, and I realized the coolant temps having a hard time staying below the 190-200 range while driving. I decided to do some in boost testing and data log (stand along ecu) both stock temp sensor and the sensor placed in the upper radiator hose/head outlet.

    Testing was done by letting the car heat up to about 195 while stopped dead, launching off launch control, taking to the top of each gear all way to 4th. I saw temps go up to 205+. The temps testing was don was 90+ degree day with 50+% humidity.

    I ended up removing the (****ty) CX racing intercooler (28x9x3" with 2.5" outlet) as a simple airflow test (just a can of spray smoke) revealed not a whole lot of air is getting through. Before this however, I tried ducting the radiator, to no avail with this intercooler installed.

    I downsized to a smaller tube and fin intercooler (28x7x2.5" with 2.5" in/outlet) to free up some airflow to the radiator. I removed the ducting in the process. I just did some datalogging, and even with lower ambient temps (72 F outside which less humidity), still see it climb to 204 if my previous test conditions are repeated.


    I am at a little bit of a lost as to what to do next.

    Setup:
    CX (koyo imitation) Radiator (thinking of replacing. It came with the car)
    Sr20DET
    Stock thermostat
    GT28R
    11psi
    260 RWHP
    S14 (stock bumper)
    Setrab OIl cooler and Greddy oil block with thermostat in right bumper opening

    Notes:
    1) Tried bleeding the radiator with cap off, letting it heat up until thermostat opened and car jacked fairly high up (just the front). There were some bubbles right before the thermostat opened.

    2) With the fans on (set through STACK gauge thermostat), the car cools right down (2 SPAL 12" huge flow fans (forgot the CFM)). Seems as if not alot of flow is going to the radiator.

    I haven't done any ducting yet to the new intercooler. Any idea on how to get temps back into check without going drastic?? I have a feeling, for my mild setup, even with CX Radiator, it should be running below 200F deep into boost/WOT.

    Thanks!

  • #2
    How are the fins on your radiator? if the fins are all messed up the radiator wont flow enough air no matter how you duct it.

    Comment


    • #3
      Fins (from what I can tell since I have both condenser and SPAL fans in place)) look to be in good condition. I can confirm tomorrow.

      Also forgot to mention: I also have a A/C condenser in place. However, when doing the simple airflow test and the fact that the fans pull air right through both systems leads me to believe it is not too much of a restriction

      Comment


      • #4
        Also check for dirt or debris in the radiator fins, less likely if intercooler condenser are in front cause they block stuff from coming through any off track excursions can kick crap up into the radiator and get stuck in the fins. decreasing the efficiency. Also are your fans directly mounted to the radiator? if so they may be blocking some airflow and causing more harm than good. Its a good idea to duct behind the radiator and mount the fans on the ducting so that it effectively pulls air through the entire radiator instead of just 2 places on the radiator.

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        • #5
          I know this will sound stupid, but do you have your a/c on? Mine would always sit around 190* water temp with it on as opposed to 170 with it off (aftermarket gauge obv). On track I see 200-210 sometimes, obviously not using a/c lol. I do not have an oil cooler and am using basically stock aero.

          FYI I'm using the stock shroud and fan but it doesn't sound like idle/sitting is causing any issues with being able to pull air in.

          I assume your oil cooler isn't touching the radiator...

          Dirty fluid in the radiator? Any additives being used? (I actually just run water and some coolant, thanks to new england)
          97 Kouki SR 240

          Comment


          • #6
            The A/C itself shouldn't be on (unless there is a constant live connection elsewhere apart from the interior panel HVAC unittkeeping it on).

            No issues idling whatsoever.

            Oil cooler isn't in fron of the radiator but in the right bumper opening (competely separate from the radiator air circuit).

            I am not entirely sure on dirty fluid as I drained and replaced the fluid recently (which led me to burb the system several times over). No additives whatsoever, just 50/50 Prestone mix

            Comment


            • #7
              Originally posted by Cbettis87 View Post
              Also check for dirt or debris in the radiator fins, less likely if intercooler condenser are in front cause they block stuff from coming through any off track excursions can kick crap up into the radiator and get stuck in the fins. decreasing the efficiency. Also are your fans directly mounted to the radiator? if so they may be blocking some airflow and causing more harm than good. Its a good idea to duct behind the radiator and mount the fans on the ducting so that it effectively pulls air through the entire radiator instead of just 2 places on the radiator.
              Ducting may be an issue. I will remove one of the fans and see if it makes a difference (and if it does, I will just fab up a shroud with the 12" fans and a small insulated air gap between the fans and the rear of the radiator)

              Comment


              • #8
                Most likely air in the system or a small coolant leak.

                All last year I had zero issues with cooling even on hot summer track days after going to a mid mount intercooler. This year I've had problems. There was a leak that I found but it's still puking into the overflow tank too much (only getting to 185*) but still overflowing. I'm going to install a swirl pot (coolant surge tank) I'll let you know if it resolves the issue. I also tested my radiator caps (one old and one new) both tested weak. I rented a coolant pressure tester from autozone to try and find my leak.

                I'll let you know if it helps.
                Chicago Region SCCA SM # 688 http://www.scca-chicago.com
                TSSCC SM # 688 http://www.tsscc.org

                Comment


                • #9
                  Things that help - good radiator, surge tank (is your cap popping on track?), ducting from front to radiator, vented hood.
                  '18 Chevrolet Volt - Electric fun hatch for DD duty!


                  DefSport Koni Sleeve and Spring Perch Buy!!!
                  http://www.nissanroadracing.com/showthread.php?t=5902

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                  • #10
                    Originally posted by eye-5 View Post
                    Most likely air in the system or a small coolant leak.

                    All last year I had zero issues with cooling even on hot summer track days after going to a mid mount intercooler. This year I've had problems. There was a leak that I found but it's still puking into the overflow tank too much (only getting to 185*) but still overflowing. I'm going to install a swirl pot (coolant surge tank) I'll let you know if it resolves the issue. I also tested my radiator caps (one old and one new) both tested weak. I rented a coolant pressure tester from autozone to try and find my leak.

                    I'll let you know if it helps.
                    The midmount setup is actually a better setup (intercooler depending) for airflow to and through the radiator (which I suspect is an issue I am having). I may try bleeding it again this weekend and see if that fixes things (as well as checking for leaks). Also, I do not get too much coolant being pushed into the overflow when I reach to the 195 degree range (when the fans are set to kick on). Was your raditor/intercooler setup ducted at any point??

                    Def, the cap should be working and the cap does not pop at all (1.3 bar Greddy one), but I definitely have some of your recommendations on paper for future! But what is making me think it's more an airflow issue as opposed to a mechanical issue is the fact that the fans can pull enough air through the radiator to cool things down in a less than 8 seconds. I may just cut a form my own ducted hood as well.

                    Also, the overflow is not pressurizing or have a smell of gas/oil, so I don't think the headgasket is an issue (just throwing it out there).


                    Thanks for all the recommendations guys!
                    Last edited by RalliartRsX; 06-20-2014, 10:28 AM.

                    Comment


                    • #11
                      Tuning? If you are detonating, no amount of cooling will work.

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                      • #12
                        50/50 antifreeze & water will also have a detriment to your cooling. the antifreeze raises the boiling point of the water, but lowers the actual cooling capacity. you might change the mix to 75% water and see what happens. (simply drain the radiator into a bucket and refill with water, as the radiator holds about half the system volume.)

                        With more water, your overall system temp should be lower since the water transfers heat better than antifreeze.

                        Also take a close look at your raditor fins inside and make sure they're not clogged with debris. If you flushed the cooling system and knocked a bunch of scale loose from the block, it's possible that you've plugged some of the tubes in the radiator so they're not getting good water flow.


                        Another thing to look at is the efficiency of the radiator itself. use an infrared thermometer and measure the radiator temp at inlet and outlet to see how much heat the radiator is actually taking out of the coolant.
                        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

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                        • #13
                          @ logr: tuning issue is sorted (both knock sensor and audible tones were listened for when tuning). It's stock SR20DET (S13 blacktop) timing map. A/F in boost is 11.2-11.3:1. So everything should be good on that front.

                          @Matt: I am going to delve into this weekend while apart to check the fins and see what condition they are. I do not have a infrared thermometer, but was thinking to pick one up. One thing that did prompt this was how quickly the radiator seemed to heat up. Either way, thanks for the recommendations. I am adding to the list for the weekend.

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                          • #14
                            Make sure the thermostat is working properly. You could remove it and it will really help but if it was fine before and now it isn't then you'd (well, I'd) want to figure out what broke.

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                            • #15
                              UPdate:

                              1) The fins checkout pretty much perfect, so nothing to worry about there

                              2) I removed one of the fans (big heavy SPALS and depending on where the airstream goes through the radiator, the fan blades and housing restricts exit flow). I am going to take her for some data logs once the rain has subsided

                              I will attempt to bleed the system one more time after and try Matts recommendation as far as what fluids to use. However, I did see some patch work on the radiator.........from the area it's in, I don't think it will affect anything, but I will take a pic and show the class later.

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