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    Running hot and heater blowing cold air

    Hi.
    E30 started to run hot and the heater started blowing cold air.
    Is this painful or not so painful?

    #2
    no heat means air pocket in the coolant system. Could be a lot of things have you recently drained and replaced the coolant?

    what condition does your oil appear to be in? does it look like oil or a milk shake? if it looks like a milk shake its a blown headgasket.

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      #3
      No I did not. I added coolant and the temp started to go up on the gauge

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        #4
        Originally posted by 96belmont View Post
        No I did not. I added coolant and the temp started to go up on the gauge
        you need to add coolant with the bleeder opened heat on add until it comes out the bleeder which is just atop the thermostat housing. It will take a 8mm wrench to open bleeder and you cant use a 12point it wants a 6point otherwise it will strip it. I would say you have leak somewhere and adding fluid will reveal it, may be a water pump may be a hose or clamp?. hard to say, Do this on a level surface.


        oh yeah I'm assuming this is a 325e or 325i?

        does the oil look like oil on the dipstick?

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          #5
          Thanks for responding. 92 vert 325i.
          The coolant light came on when I was driving home and the temp started to go up and the heater stopped blowing hot air and the temp went up ...never got I to the red though.

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            #6
            ok hopefully u caught it before it got bad but don't go cruising around in til you have found the problem which is most likely a hose but could be water pump or radiator. Just fill it up with mixed coolant because its so cold you don't want a cracked block (with water only) in the morning. If you can get some clean cardboard boxes crush em and put em under the car this will reveal where its leaking don't get leak confused with overflo from filling it up.

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              #7
              You have a lot of air trapped in your system. Look up Jim's bleeding procedure here and follow it to the letter (don't know how many times he posted that...lots!, but it should be an easy search)

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                #8
                I'll save you the effort of a search... But in the absence of recent cooling system work, either there is a leak, which a pressure test of the cooling system will find, or there is a head gasket leak that is pumping air into the cooling system. Either of those will result in a loss of coolant. Start by filling and bleeding the cooling system and then pressure test it.

                If you don't find a leak, a simple check for a failed head gasket is to wait until the engine is stone cold and then remove and replace the cap to vent any pressure. The hoses will be soft. Drive the car for a little bit and let it completely cool down, like overnight. Then see if the hoses are hard. If they are air is being pumped into the cooling system.


                1) Using ramps or a jack get the front of the car 1' or more higher than
                the rear. That will make the radiator and bleed screw the highest point
                on the engine and facilitate removal of air.

                2) With the bleed screw open, add coolant until no more air comes out of
                the bleed.

                3) Leave the filler cap off, or at least loose, and set the heat for max
                temp and fan speed. Leaving the cap loose will prevent air that's still
                in the system from causing a "coolant fountain" once the engine heats
                up. Start the engine and allow it to warm up to operating temp. As it
                warms up occasionally crack the bleed screw to release any air and top
                up the coolant as necessary.

                4) Once the engine is at temp bring it up to 2000-2500rpm for a few seconds
                several times. Then crack the bleed until no more air is released. At
                this point the heater should be throwing lots of hot air, which
                indicates that the heater core is filled with coolant. You may have to
                repeat this a few times to get all the air out.

                5) Drive the car a bit, allow it to cool back down, and recheck the
                bleed for air. Over the next few days you may get very small amounts (a
                few bubbles) of air out of the bleed screw.
                The car makes it possible, but the driver makes it happen.
                Jim Levie, Huntsville, AL

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                  #9
                  FYI I looked at this thread trying to figure out a similar solution . It was Not an air bubble issue. The water pump was broken. It didn't leak or anything. It just ran hot and the heater wasn't working. Turns out my water pump had composite vanes and the vanes were no longer tight to the shaft. Pulley spun, but with any load the pump vanes didn't. Look for poor flow from the radiator return line to the overflow tank. If the flow isn't consistent at idle the pump may be the issue.

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                    #10
                    FYI, I know this is a very old thread. But it came up when I was searching for help with an overheating / no heater inside issue and bleeding was NOT the issue. I tried re bleeding but wasn't finding any air with multiple attempts. But I noticed that fluid flow was weak in the line from the top of the radiator back to the reservoir bottle. It is usually a good even flow. But mine was trickling and sometimes didn't flow at all. I therefore suspected either a bad pump or blockage somewhere. I first replaced the thermostat. Easy so why not try. Same issues. The pump wasn't visible leaking but I figured it was the problem due to the weak flow and I proceeded to remove it. Turned out the composite pump disc was not fully tied to the shaft. I could turn the shaft on the outside and stop the pump vane with my pinkie finger. The resistance of the water was more than the friction of the pump vane to the shaft. I replaced it with a metal impeller pump and all is well again.

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                      #11
                      wow, that is something to keep an eye on. plastic impellers have caused more people to replace headgaskets (across all makes) than anything, I think

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