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Further 940 Developments.

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  • Further 940 Developments.

    Newer Volvo guy here.

    Wondering if folks can offer some help to put together the developing puzzle.

    So my 1994 940 Turbo wagon is now having a smattering of symptoms that make me my head gasket blown? Is this all there is? What the meaning of life? What is my purpose?

    Here's what's happened:

    • Replaced water pump in last month or so, didn't know to "bubble it" and let the air out that had been introduced into the system.
    • Filled coolant and a day later it was empty, so refilled again.
    • Finally released the pressure, but hoping it's not too late.
    • Shortly after starting, engine struggles and sputters, white smoke sometimes appears.
    • Heater stopped working but I ran engine with coolant reservoir top off, and now heat works again ONLY on full blast.
    • Checked fuses yesterday and a 30A fuse on Fuse 16? (AC Fan Blower motor if I can recall) was shorted to the point it had melted the fuse completely.
    • There is white smoke that my brother has said is "coolant burnoff" coming from the left side of the engine. Looks maybe like from the exhaust manifold gasket which I had replaced 2 years ago. Could also be from a crack in the head but haven't looked to see yet.

    Ran the codes and here is what I got:
    A6 - 144
    B3 - 122
    B6 - No code

    Cleared my MAF sensor yesterday FYI. Seems to have helped a bit maybe. Check Engine light is still on.

    Thoughts on how to proceed? I have Chilton's manual but wondering if anyone has any ideas here.


  • #2
    Hey there! I'm not sure exactly what your issue is, but to my knowledge "burping" the coolant system isn't super necessary. The coolant reservoir is the highest point in the system and it's usually pretty good about letting air out by itself. The white smoke is a little concerning, though. Are you sure coolant isn't leaking from anywhere else? Also, how does the oil look?
    Customer Service guy | [email protected] | 800-444-6473 ext. 181


    • #3
      It's not milky, and the idle smooths out once things warm up. Thinking maybe some sort of sensor malfunction?


      • #4
        That's a possibility, I also just talked to a coworker who suggested you might want to get one of these kits to test if you're getting exhaust gas mixing with coolant:

        This is a pretty good way to make sure whether or not the head gasket is blown.
        Customer Service guy | [email protected] | 800-444-6473 ext. 181


        • #5
          Hello Hunter,
          What is the repeatable result of short engine runs / drives? Do you get air pressure in the expansion tank or a significant loss of coolant? Was the coolant loss happening before the water pump change? I would agree that the system generally burps its self pretty well.

          I had a 850 with a blown head gasket that was shoving exhaust gasses into the coolant system. I could drive the car about 30 miles and then I had to pull over and rlease the pressure from the coolant expansion tank because there was so much air in the system, the engine couldn't stay cool and so temp gauge would begin to rise.

          As for your cabin heater issue, I wanted to mention my 940 had a coolant diverter valve just between the engine and firewall. If it is cracked or otherwise leaking, the coolant could be disappearing before it gets into your heater core. However, when mine blew, there was coolant splattered all over the engine bay, and was pretty obvious.

          Finally, my 940 also was leaking coolant out of the small coolant hoses that run into and out of the oil cooler heat exchanger. Maybe a leak from there would be splattering onto the exhaust and burning off? This leak, by the way, caused a blown head gasket as I was driving and had my hand on the wheel right in front of my temp gauge...

          Good luck, let us know any updates.