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Coolant smoke off exhaust manifold?

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    Coolant smoke off exhaust manifold?

    Hey guys, sorry for the long first post!

    I've been lurking here and at e30tech.com for a while and have learned quite a lot. I recently bought my first E30 about 3 weeks ago. It's a 1986 325 2dr. One of the first things I learned when acquiring a "new" E30 was to change out, at the very least, the timing belt, tensioner, and water pump. I recently finished this job a couple of days ago, but have run into a mysterious problem. I used the search function extensively, and found some leads, but no one with the same exact symptoms I'm having.

    When doing the t-belt work, I drained the coolant out of both block and radiator then replaced with new coolant after the job was done. Pulling the block drain plug, it created the obvious mess of coolant all over the exhaust manifold. The engine runs just fine now that everything's back together, but there's a good amount of white smoke (smells like coolant) coming from around the exhaust manifold area once the car gets up to temp. I thought this was normal from the coolant burning off the exhaust/block from the block drain, but it wont stop. It's not thick white plumes of smoke, but enough to be concerned/visible. Another thing that confuses me is that the smoke never exits the tail pipe, the engine doesn't overheat (even checked with a non-contact thermometer to make sure the gauge wasn't lying), and the coolant level doesn't seem to drop a drastic amount. The exhaust from the tail is nice and clear and smells just fine with the usual drips of clear water. The coolant is making the full cycle through the engine and radiator as all the hoses got warm and the coolant was making it back to the reservoir. I checked the oil, which had no bubbles or milkyness. I have not driven the car for fear of furthering the problem, but I let the car idle at temp for about 30 minutes last night, all the while the smoke kept coming.

    Another thing that worried me was that when I undid the bleed screw, nothing came out. And I mean nothing, I took the bleed screw completely out of the housing and no air, steam or steady flow of coolant. At one point, there appeared to be a small dribble of coolant from the t-stat housing, but it had stopped before I noticed it, maybe a tsp-tbsp of coolant it seems. I'm assuming this is a blocked bleed hole, and that will be remedied shortly. If it were excess air in the system shouldn't the engine be running hot?

    I will be trying to diagnose the problem over the weekend, and if the problem persists, I will get a video and post it up. Thanks in advance for any help!

    #2
    how long ago did you do the work? coolant can leave some residue but i wouldnt expect it to smoke after the first 2-3 times of driving it, depending on length of the drive of course.
    Your signature picture has been removed since it contained the Photobucket "upgrade your account" image.

    Originally posted by TimKninja
    Im more afraid of this thread turning into one of those classic R3v moments, where Pizza gets delivered.

    Comment


      #3
      I did the work over the course of last weekend/this week, due to me buying the wrong year pump at first (I did NOT use this pump/ start the engine, just delayed finishing), having to get the correct one etc. etc. I started the car two nights ago for barely 5 minutes just to make sure the engine was running well (no bleeding was done, though it didn't even get up to temp, smoking was noticed then too), had a leak yesterday morning from a loose coolant hose, last night topped up and tried the bleeding procedure and when I noticed the prolonged smoking. The car has NOT been driven since the new t-belt/ flush, in other words. Do I just need to take it for a light spin to see if the smoking goes away and/or the car starts running hot?

      Comment


        #4
        The ideal thing to do any time coolant gets on parts of the engine is to wash it off with plain water. That avoids the smell of hot coolant and prevents it from smoking. If you let the engine dry before starting it, it becomes immediately obvious if there is a coolant leak.

        With only 5 minutes of running I doubt that all of the coolant has been burned off. The engine will need to run a bit longer to vaporize all of the coolant.

        Before going further you need to make sure that the cooling system is fully bled. Use:

        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 2000-2500 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

        Comment


          #5
          ^ what he said

          Comment


            #6
            Thanks for the rundown of the bleed procedure. I had followed a similar process the first time, and today I did it again (after unclogging the t-stat bleeder) and followed your instructions exactly. Turns out I had already bled the system fairly well as I immediately got a steady stream of coolant from the bleeder, but there was still smoke.
            After triple checking the engine temp, oil condition and that there were no bubbles, I decided the only thing left to do was drive it for a bit to see if the smoking would subside. I took it for a spin around about a 6 block radius loop. Halfway through the loop, I couldn't see any smoke, but I could smell burning coolant (no high temps or odd running). I pulled over, and a big plume of smoke came out from underneath the car. With bated breath I popped the hood and a MASSIVE cloud of white smoke emanated from the hood. After panicking for about 5 minutes and checking all the systems with the engine running, the smoke was practically gone! By the time I had arrived at home, there was no more smoke to be seen, only the smell of previously burnt coolant. I took her for another, more spirited drive up the highway and down some smaller roads for about 20 minutes, and she's running just fine now
            I must've had quite the coolant puddle in my exhaust........
            Thanks again for all the help!

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