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95 LT-1 running hot & "Low coolant" Lamp

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  • #1

    95 LT-1 running hot & "Low coolant" Lamp

    1995 Trans Am LT-1
    Hi,
    I have replaced my water pump, thermostat (3 times), computer temp. sending unit, flushed my system more than once and my car still gets too hot when just sitting idling in Park. I am getting a "low coolant" light when this happens. It seems like some air could be trapped somewhere but I have bled it off and there's no air trapped in there. The radiator and heater core have good flow and they do not appear to be plugged. The fans and relays are just fine. The fan kicks on when the air conditioning is turned on. I am just about at my wit's end. The engine gets up to around 220-230 when I am just sitting and idling before the fans kick on. When the temp gets past about 200, the low coolant light comes on and stays on. I have the engine and air temp. sensors connected correctly. Any ideas on what could be causing it to run hot and the "Low coolant" light to come on?
    Thanks,
    Craig
    Tags: None
  • #2
    Hmmmmm....the suggestions I would have to lower engine temps would be....

    1) Install a lower degree thermostat (160 degree)
    2) Reprogram your fans to turn on earlier or get a manual fan bypass
    3) Have proper amount of coolant
    4) Make sure no air is trapped (using the 2 brass screws right by the waterpump)

    How hot does it exactly get? Stock programming makes our fans kick on at I believe 226 degrees...or somewhere around that.

    As for the low coolant light, my best guess would be to start with the basics. Make sure your coolant is full (I know....obvious, but you'd be surprised), bad sensor, etc....

    Oh yeah, and welcome to the boards!
    black 95 t/a, a4, beefed up tranny w/ higher stall converter, transgo shift kit, trans temp gauge, trans cooler, richmond 3.73's, loudmouth, hypertech programmer, 160 thermo, descreened maf, TB bypass and airfoil, trick flow intake elbow, underdrive pulleys, moroso cai, edelbrock panhard rod, bmr stb, slp sfc's, fiberglass firehawk hood, hawk pads, taylor wires, ngk plugs, royal purple fluids,...and hopefully more to come

    Comment

    • #3
      That sounds pretty typical of an LT1. Low temp fan kicks on at 226. High temp at 235. You can fix that with getting the computer reprogrammed or getting a manual fan switch.

      The low coolant sensor goes bad in the LT1 pretty frequently. Here is how to replace it. http://shbox.com/1/low_coolant2.jpg

      Since you are new to the board, welcome. Here are your 2 best sources for information on your car. http://shbox.com/page/index.html and http://www.projecttransam.com/ . There isn't much that isn't answered in those 2 places.
      2002 Electron Blue Vette, 1SC, FE3/Z51, G92 3.15 gears, 308.9 RWHP 321.7 RWTQ (before any mods), SLP headers, Z06 exhaust, MSD Ignition Wires, AC Delco Iridium Spark Plugs, 160 t-stat, lots of ECM tuning

      1995 Z28, many mods, SOLD

      A proud member of the "F-Body Dirty Dozen"

      Comment

      • #4
        Reprogramming Fan Temps...

        Jeff,
        Thank you for your suggestion. I understand that LT-1s run on the hot side. Have you ever thought of relocating the computer sensor and installing it in the head where the temp sending unit is? Wouldn't the coolant temp be hotter at the head than at the pump? I will search other threads for reprogramming. I only have one other question: I have a 16-pin connector under the dash. My emissions decal under the hood says it's an OBD Type I. I have not been able to find a code reader for this configuration?

        Comment

        • #5
          Originally posted by 95RagtopTransAm
          Jeff,
          Thank you for your suggestion. I understand that LT-1s run on the hot side. Have you ever thought of relocating the computer sensor and installing it in the head where the temp sending unit is? Wouldn't the coolant temp be hotter at the head than at the pump? I will search other threads for reprogramming. I only have one other question: I have a 16-pin connector under the dash. My emissions decal under the hood says it's an OBD Type I. I have not been able to find a code reader for this configuration?

          Your 1995 car is a cross-breed as far as scanning goes.

          The connector is a OBDII style plug, but The PCM is OBDI. You will need to use a OBDII cable on an OBDI scanner.

          Clear as mud?
          Tracy
          2002 C5 M6 Convertible
          1994 Z28 M6 Convertible
          Current Mods:
          SLP Ultra-Z functional ramair, SS Spoiler, STB, SFCs, Headers, Clutch, Bilstein Shocks, and TB Airfoil. 17x9 SS rims with Goodyear tires, 160F T-Stat, MSD Blaster Coil, Taylor wires, Hurst billet shifter, Borla catback with QTP e-cutout, Tuned PCM, 1LE Swaybars, 1LE driveshaft, ES bushings, White gauges, C5 front brakes, !CAGS, Bose/Soundstream audio, CST leather interior, synthetic fluids

          Comment

          • #6
            Originally posted by 95RagtopTransAm
            I only have one other question: I have a 16-pin connector under the dash. My emissions decal under the hood says it's an OBD Type I. I have not been able to find a code reader for this configuration?
            I too have a 95 T/A, and have the same style configuration. The reason is because in 1995, it was a transitional year. We indeed do have OBD-I, but we have it with an OBD-II style port. 1996 was when the full OBD-II conversion was made.

            There are many code readers that will work. Autozone will be able to pull up codes for free. If you go to a dealer, I believe they use "Tech 2" for us as well.

            As for reprogramming, there are many options. Things like hypertech and other handheld things are good for reprogramming your fans (I'm assuming you were talking about your fans for reprogramming). A mail order tune can also do the same thing. On the home page of this site, there is a link for MADZ28 I believe it is. As long as you buy the cable ($90 I believe), you can subscribe to his service, and you will be emailed a program that you download straight from you lap top to your cars computer.

            Another option is a manual fan bypass.
            SLP has them here for $69.95. I'm sure other sites like summit, lmperformance, or jegs will have them as well....possibly cheaper too.
            black 95 t/a, a4, beefed up tranny w/ higher stall converter, transgo shift kit, trans temp gauge, trans cooler, richmond 3.73's, loudmouth, hypertech programmer, 160 thermo, descreened maf, TB bypass and airfoil, trick flow intake elbow, underdrive pulleys, moroso cai, edelbrock panhard rod, bmr stb, slp sfc's, fiberglass firehawk hood, hawk pads, taylor wires, ngk plugs, royal purple fluids,...and hopefully more to come

            Comment

            • #7
              Ya beat me to it TraceZ
              black 95 t/a, a4, beefed up tranny w/ higher stall converter, transgo shift kit, trans temp gauge, trans cooler, richmond 3.73's, loudmouth, hypertech programmer, 160 thermo, descreened maf, TB bypass and airfoil, trick flow intake elbow, underdrive pulleys, moroso cai, edelbrock panhard rod, bmr stb, slp sfc's, fiberglass firehawk hood, hawk pads, taylor wires, ngk plugs, royal purple fluids,...and hopefully more to come

              Comment

              • #8
                I've got an AutoXray http://www.autoxray.com
                Here is the specific cable for the AutoXray scanner.
                http://www.autoxray.com/products.aspx?sub=cables&id=11

                You could also go with the route of getting a laptop cable and downloading the software like freescan. (There are links to them on the akm website) Here is where you can get the cable for using a laptop http://www.akmcables.com .
                2002 Electron Blue Vette, 1SC, FE3/Z51, G92 3.15 gears, 308.9 RWHP 321.7 RWTQ (before any mods), SLP headers, Z06 exhaust, MSD Ignition Wires, AC Delco Iridium Spark Plugs, 160 t-stat, lots of ECM tuning

                1995 Z28, many mods, SOLD

                A proud member of the "F-Body Dirty Dozen"

                Comment

                • #9
                  Originally posted by 95TransAm
                  Autozone will be able to pull up codes for free. If you go to a dealer, I believe they use "Tech 2" for us as well.
                  The Autozone by me will only do OBD2 vehicles.
                  2002 Electron Blue Vette, 1SC, FE3/Z51, G92 3.15 gears, 308.9 RWHP 321.7 RWTQ (before any mods), SLP headers, Z06 exhaust, MSD Ignition Wires, AC Delco Iridium Spark Plugs, 160 t-stat, lots of ECM tuning

                  1995 Z28, many mods, SOLD

                  A proud member of the "F-Body Dirty Dozen"

                  Comment

                  • #10
                    Originally posted by Jeff 95 Z28
                    The Autozone by me will only do OBD2 vehicles.
                    I had no idea about that. I've never had to get my car scanned there, so I wouldn't have known that. I figured that since our scanner doesn't have to be hooked up to the battery like an OBD-I with an OBD-I port would have to be that it wouldn't be a problem anyways....but I'll take your word on that one, you're probably right anyways.

                    95Ragtop~I do suggest though that if you pay to get it scanned (as if autozone can't), you might as well take a look at how your engine is performing while you get it scanned. This past saturday, I took my car to a GM Dealership where my buddy is a tech at. He hooked up his "Tech 2" Scanner to my car to check a couple things out even though I didn't have an SES light. He said he wasn't sure if OBD-I stored codes after you remove your SES light when it comes on, but he checked anyways, and I had no codes. He then started my car and we looked at real time data of my engine. It was the first time I ever witnessed this, and I must say it was one of the coolest things I have ever saw! It was showing my exact RPM's in comparison to a recommended RPM. It shows alot of other things too, throttle position, volts, etc.... I also finally got to take a look at my timing. I'm at about 19-20 degrees advance at idle, and when we revved it to about 3500 to 4 grand or so, I believe it went to about 35 or so degrees advanced. I would have written everything down, but he was busy and he snuck out really quick to do this for me. None the less though, some neat stuff
                    black 95 t/a, a4, beefed up tranny w/ higher stall converter, transgo shift kit, trans temp gauge, trans cooler, richmond 3.73's, loudmouth, hypertech programmer, 160 thermo, descreened maf, TB bypass and airfoil, trick flow intake elbow, underdrive pulleys, moroso cai, edelbrock panhard rod, bmr stb, slp sfc's, fiberglass firehawk hood, hawk pads, taylor wires, ngk plugs, royal purple fluids,...and hopefully more to come

                    Comment

                    • #11
                      I use my scanner everyday. I have a ram mount cup holder mounted to the top of my dash and I put my scanner in it (I'll take a picture of it later). I've been watching the knock sensor data lately to see if I can put more timing advance in it. That thing makes no sense to me. I'll look at it one minute and it will say 72, then a few minutes later it will say 140, then it will say 55, then 23, then 180, then 12. I thought it was supposed to be a cumulative total. Anyway it's neat watching that stuff. I think I need a little more A/C refrigerant. It's only going to about 250 on the high side. Oh and the cup holder is right below the mirror so the passenger side light shines right on the scanner display. It couldn't have worked out better if I had tried.
                      2002 Electron Blue Vette, 1SC, FE3/Z51, G92 3.15 gears, 308.9 RWHP 321.7 RWTQ (before any mods), SLP headers, Z06 exhaust, MSD Ignition Wires, AC Delco Iridium Spark Plugs, 160 t-stat, lots of ECM tuning

                      1995 Z28, many mods, SOLD

                      A proud member of the "F-Body Dirty Dozen"

                      Comment

                      • #12
                        Thanks to ALL!

                        Thanks everyone for your help!
                        F-Body Message Forum ROCKS

                        Comment

                        • #13
                          Originally posted by 95RagtopTransAm
                          Thanks everyone for your help!
                          F-Body Message Forum ROCKS
                          Yes this place does!
                          2002 Electron Blue Vette, 1SC, FE3/Z51, G92 3.15 gears, 308.9 RWHP 321.7 RWTQ (before any mods), SLP headers, Z06 exhaust, MSD Ignition Wires, AC Delco Iridium Spark Plugs, 160 t-stat, lots of ECM tuning

                          1995 Z28, many mods, SOLD

                          A proud member of the "F-Body Dirty Dozen"

                          Comment

                          • #14
                            Originally posted by 95RagtopTransAm
                            Thanks everyone for your help!
                            F-Body Message Forum ROCKS
                            Indeed....saved my arse some $$$ many times...and headaches for that matter

                            Jeff, if you would be willing to post pics, I would be interested in seeing how your scanner is hooked up. Also what kind do you have and how much if you don't mind me asking? I really want one now after this past saturday at my buddy's work....that was just the coolest thing I've ever seen
                            black 95 t/a, a4, beefed up tranny w/ higher stall converter, transgo shift kit, trans temp gauge, trans cooler, richmond 3.73's, loudmouth, hypertech programmer, 160 thermo, descreened maf, TB bypass and airfoil, trick flow intake elbow, underdrive pulleys, moroso cai, edelbrock panhard rod, bmr stb, slp sfc's, fiberglass firehawk hood, hawk pads, taylor wires, ngk plugs, royal purple fluids,...and hopefully more to come

                            Comment

                            • #15
                              Low Coolant Sensor

                              Originally posted by Jeff 95 Z28
                              That sounds pretty typical of an LT1. Low temp fan kicks on at 226. High temp at 235. You can fix that with getting the computer reprogrammed or getting a manual fan switch.

                              The low coolant sensor goes bad in the LT1 pretty frequently. Here is how to replace it. http://shbox.com/1/low_coolant2.jpg

                              Since you are new to the board, welcome. Here are your 2 best sources for information on your car. http://shbox.com/page/index.html and http://www.projecttransam.com/ . There isn't much that isn't answered in those 2 places.
                              Would a bad low coolant sensor cause the computer to control the cooling system differently?
                              Thank you.

                              Comment

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