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Heating Problem on 2000 Honda Insight- 180K Miles

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  • #474106
    MikeMike
    Participant

      So I’m a technician and this customer brings his car in for heating issue. He states that when he goes down the road, doesn’t matter how fast he goes, sometimes the heat fades away and blower would blow cold for a bit and then it would get back to normal heat. Customer says it is a significant heat difference. So I couldn’t duplicate the problem and i drove this car for almost an hour.

      First obvious things i have noticed and done to it are replaced the thermostat, replaced the clogged radiator and replaced the leaking heater core. So I did all this about couple weeks ago and I heard today that the customer is having the same issue not as often but he has experienced it couple times in 2 weeks.

      I verified bunch of times that heater control valve(water valve) is working just fine. Coolant is bled properly and no overheating issue at all. The car actually blows really nice and warm. I did a cylinder leak down test and found almost no leakage. It is a smaller 3 cylinder hybrid motor.

      So at this point I am really running out of ideas/guesses as to what could be causing this problem. I would really appreciate If the techs and Eric can give me an educated guess pls.

      Thank you

    Viewing 15 replies - 1 through 15 (of 15 total)
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    • #474135
      toyodagregtoyodagreg
      Participant

        I would check the operation of the blend door. See if its maybe loosse or broken. what kind of hvac controls does this car have?

        #474143
        MikeMike
        Participant

          Customer left the car over the weekend and I had a chance to drive around and try to duplicate the problem after i replaced all those components. So I went from hot to cold, cold to hot so many times and had no issues with it. This car is automatic HVAC. It has a nob and It tells you the degrees as you turn the nob either way such as 85Degrees and whatnot on the display. Blend door is operated by the actuator which controls the cable for the door. When I removed the case for the heater core, I played with the blend door to make sure it was not stuck or anything. It was moving just fine. I dont know what else can cause heat to pause and resume..

          #474186
          college mancollege man
          Moderator

            usually when the heat comes and goes.Its air in the
            system.if you rev the engine to 2500-3000 does the heat
            start to get hot in the car? if it does then air is still
            trapped.repeat the bleeding procedure.

            #474283
            MikeMike
            Participant

              The car blows heat at all times when I have it. Customer has a commute of approximately 40miles. So generally he is on the highway. At highway speed, it blows hot and all of a sudden cool air would start coming out of the vents. this would be like that for a little bit and then it would go back to hot air. So if there was any air in the system, most likely car would overheat. He does not have any issues like that. Temp gauge is perfect where it’s supposed to be.. 50-60mph on a highway speed, cool air would come out of the vents..after a while, it would go back to hot. Is there anyone else that want to suggest or give any ideas?

              #474305
              toyodagregtoyodagreg
              Participant

                my theory is that since its auto climate control, it has a cabin temperature control, so i would believe it to be normal for it to adjust, when it gets too hot inside it will adjust the temperature of the air coming out to adjust the cabin temperature, and then when it cools down i would say it will change the temperature.

                #474312
                MikeMike
                Participant

                  That’s a good approach but there are 2 things..when there is auto climate you choose that option. I mean there is an ” auto button” you push on..that adjusts the temp. In this case customer is not using the auto button. Even if he did, the blower shouldn’t blow cold and run at the same speed..that’s my theory..anyone else has any ideas?

                  #474316
                  Jason Alexmckrishes
                  Participant

                    It’s possible you may have air in the system or your new thermostat may not be working properly. Although you installed a new thermostat, I would double check it to make sure it is working properly. You might wanna go with an OEM thermostat if you haven’t already. Also try re-bleeding the system using the official honda bleed procedure. This car is unique. It might take a while to bleed the system properly.

                    #474322
                    MikeMike
                    Participant

                      Let’s think about this.. The car does not overheat and has constant good heat all week long.. but some days it has this heat problem. So if this was related to air in the system which I bled for about 30 minutes and thermostat, It would happen every time you drive the car. Customer says that in 2 weeks, it happened twice only.. heater core and the radiator are all OEM Honda products. Nothing on this car is after market. Any more ideas? How about some restriction inside the engine? Coolant restriction inside the engine block coolant passages? or inside the cylinder head? Cylinder leak down test checked perfect. No leakage. I wouldn’t think it would be related to head gasket..The oil condition and level look normal. No white smoke or hesitation with this car. No power loss.

                      #474329
                      Jason Alexmckrishes
                      Participant

                        Not too sure about a restriction in the coolant passages. I would expect more symptoms out of this. How about the water pump? Maybe it’s not pumping the coolant properly.

                        #474343
                        MikeMike
                        Participant

                          Water pump is driven by the serpentine belt and the only way water pump can fail is it can freeze up(wont turn anymore), water pump can leak or shatter internally which would make so much noise. I do not have any of these symptoms..

                          #474353
                          Jason Alexmckrishes
                          Participant

                            Lets think some more. You have.

                            1. Changed the radiator
                            2. Changed the thermostat
                            3. Changed the heater core
                            4. Verified the heater control valve is working
                            5. Verified the blend door/actuator/motor, etc. is working
                            6. Verified the water pump is working
                            7. Checked all hoses for proper operation
                            8. Properly bled the system.
                            9. Performed cylinder leak down test with almost no leakage
                            10. Verified proper coolant level

                            Customer state’s that while driving down the road (at any speed) the heat will fade away and the air will blow cold for a short time. After replacing the first 3 items, the symptoms still persist, but are less prior to repair. You also mentioned that this happens around 50-60 mph. You also mentioned that the problem is occuring with the hvac in manual mode and not automatic climate control. Also you mentioned the engine temperature was perfect. Question:

                            1. Where you able to duplicate the problem?
                            2. Is the problem occuring at any speed or just highway speeds?
                            3. What is the temperature of the engine when the problem was occuring?
                            4. Does the temperature of the engine fluctuate at different speeds?
                            5. When the problem occurs, what is the temperature of the coolant going into the heater core?
                            6. When the problem occurs, does maximizing the heater control make a difference?

                            If you had a restriction inside the engine, I would think you would have some overheating issues. This problem seems to occur randomly, but there is a significant difference in air temperature when the problem occurs. The problem could be actuator/motor, blend door etc., but your customer has the settings on manual control (and already set at desired temperature) when the problem occurs. Since there is a significant change in air temperature, I am curious to know the temperature of the coolant going into the heater core when the problem occurs and also the engine temperature. So we need to find out the temperature of the coolant going into the heater core when the problem occurs (you could also check it during normal operation) and/or if there is even any coolant going in it at all during the problem.

                            If the coolant going into the core is low (during the problem), then maybe the thermostat is staying open, but if this is true, I would imagine your engine temperature should be decreasing as well. If the coolant going into the core is hot (during the problem), then you can verify hot coolant going into the core. Then check the heater core itself to see if it’s getting the coolant or getting restricted at the time of the problem. If there is a restriction, then why? Bad core, air possibly? If the core is hot as well, then the air should be hot. At this point maybe there is a motor/actuator, fan etc. problem.

                            There may not be any physical evidence that the water pump is failing, but maybe so? There maybe something on the inside going on that we can’t see or hear. Is the water pump providing adequate flow? Maybe at speeds of 50-60mph it’s sometimes having trouble pumping water to the core and possibly the rest of the engine, but then you said the problem happens at lower speeds as well. We could find out by monitoring the engine temperature when the problem is occuring.

                            Hope this helps.

                            #474533
                            toyodagregtoyodagreg
                            Participant

                              another idea, im not sure how similar the hybrid systems are between the insight and the prius, but prius has a seperate hot tank mounted in the front fender that stores hot coolant for cold starts. Depending on how the insight hybrid system operates, it could be that when the engine stops running and when the hybrid battery is running the drivetrain, there isnt much coolant flow therefore it cools of in the heater core. Just a thought throwing it out there.

                              #474565
                              MikeMike
                              Participant

                                I’m gonna call the Honda Tech Line tomorrow.I wanna talk to them and see if they have seen any cases like this. The most annoying thing is that it does not happen when i drive the car. I drove this thing full heat literally an hour on the highway and around town..The customer says he has had the car over 7 years and this is the first year this is happening..Also there is no hot tank in this car but again, this car is first generation hybrid so the motor runs at all times with or without battery assist.. so does the water pump..I think as long as the water pump turns, it has to flow the coolant all around cooling components. I can’t wait to see what tech line is gonna tell me tomorrow..

                                #474576
                                Phil GrimseyPhil Grimsey
                                Participant

                                  Is the serpentine belt slipping/pulley loose on water pump?

                                  #474854
                                  EricTheCarGuy 1EricTheCarGuy
                                  Keymaster

                                    Air in the cooling system. Especially since the cooling system was opened up to change those parts. I can’t stress enough how important it is to purge the air PROPERLY from the cooling system anytime it’s opened for service.

                                    Air usually collects in the heater core. There are times under certain conditions where coolant will enter the heater core and you will have heat, once the air gets back in the heat goes away. What you describe are the classic symptoms of air in the cooling system.

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