Announcement

Collapse
No announcement yet.

Need some thoughts regarding an 89 325is overheating issue

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

    Need some thoughts regarding an 89 325is overheating issue

    Ok guys and gals, I have always wrenched on my vehicles but recently I have had a bad run working on my sons 1989 E30 325is. Last summer it ended-up with a leaking water pump. Since I was going to be tearing into it I decided to also do the timing belt, all other reciprocating belts, the thermostat, all of the hoses and the rotor and distributor cap. When I went to bolt everything back up I realized that the place I had purchased the timing belt/water pump kit from had sent me the earlier water pump and not the correct one so I had to disassemble everything again and bought the correct pump from AutoZone.

    My issue is that when I start the car up cold, it sounds and runs good, but I am hearing a noise that almost sounds like the water pump making noise. Once the car has warmed up the temp gauge continues to rise toward the red and the car starts to cut out and run like crap at which point I turn it off. In checking this I have:
    1) Removed my new thermostat and checked it in a pan of hot water and it is actuating as its supposed to. I have also been able to open the bleed port on top of the thermostat and have coolant come out to purge the system. It has enough anti-freeze in it so thats not the issue.
    2) I replaced the coolant temp sensor (the brown single pole sensor at the front),
    3) I have a new ECU coolant sensor but have not replaced that as it was a later purchase and appears to require pulling the fuel rail to gain access to remove it.
    4) As far as other miscellaneous items I have also replaced the crank sensor, cleaned my IAC valve, and checked my TPS to verify it was working correctly and adjusted properly before re-installing it.I also replaced the distributor cap and rotor and have also replaced the main and fuel pump relays as well as replacing my fuel filter. None of those items should really have any affect on the car overheating still but I wanted to mention what had been replaced.
    5) Ignition-wise I double checked my timing when I re-installed the correct water pump and it was spot on. All belts are tensioned correctly.
    6) As far as other possible culprits tying back to the original overheating situation with a possible head gasket issue, the oil is clean and no white exhaust smoke indicating a blown head gasket.

    Again, when I start the car cold, it runs great with no hesitation when giving it throttle. After about 2-5 minutes I hear a noise which sounds like the pump which then seems to subside as the engine warms. Once the engine warms it just continues to climb. The gauge is a little jumpy but continues to rise towards red. As it gets hotter it starts to cut-out and the vacuum gauge drops over. trying to gas it makes it worse. After shutting it down and letting it cool to a point where the temp gauge read in the middle it still does not want to run correctly. After it cools down completely I am sure it will run well again for a short period of time.

    Ideas, or thoughts are appreciated. I am thinking:

    1) The new replacement water pump could be bad out of the box.
    2) The radiator could be clogged.
    3) The ECU temp sensor could be causing some issues but I am thinking that would potentially cause the poor performance, but would not affect the temp gauge and the overheating situation.
    4) Possibly a bad gauge with it jumping around a bit the way it does.

    I wonder if I hooked an aftermarket temp gauge to the sensor would I be able to read and verify it is indeed heating up too far? I assume it is, and that the hot condition is causing the car to start running poorly, but at this point maybe its some other issue and the car simply thinks its running hot and really isn't. I would gladly pop for a cheap attometer temp gauge if I thought it would work. I guess as long as replaced the current temp sensor with the aftermarket one to test it I should at least be able to verify the stock gauge is reading correctly.

    If it is, which I expect, then I would think its either the replacement "new" water pump, or a clogged radiator.


    Let me know your thoughts...

    #2
    get a $30 infrared thermometer at harbor freight and verify your temps

    1989 Coupe build thread: http://www.r3vlimited.com/board/showthread.php?t=312012
    IG: @mitchlikesbikes

    Comment


      #3
      Hmm..never knew they carried those. Sounds like a plan thanks for the tip.

      Comment


        #4
        Sears carries a Craftsman one for $50. Very useful.
        AWD > RWD

        Comment


          #5
          Ok, tested the temp off of the thermostat housing with the IR thermal gun. As always the cold car starts and runs fine idling ok. As the engine warms I stay to hear something like a slight swirling noise it's not the belt, but it seems top come from the water pump and fan area. It may simply be the viscous fan clutch engaging as it warms. As the temp gauge in the car climbs I can see the thermostat housing ir reading is climbing. It hits about 210 as it climbs to the red. 180 also correlates to a rather high position on the gauge.

          It would seem that the thermostat would open at around 180-190, but unfortunately I am uncertain of what temps I should expect to see as they correlate to the gauge/needle position. Maybe 210 is too hot and the fans clutch is messed up. Just not sure that 210 should equate to that point on the gauge.

          Really starting to think the rough running could be related to the cst for the ecm. That thing is really tough to get to even with the gauge sensor removed. Maybe need to buy a decent 19mm crows foot and try that.

          Comment

          Working...
          X