Announcement

Collapse
No announcement yet.

Cooling issue?

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

    Cooling issue?

    I have an '89 touring with an M52 swap. Swap was done professionally for the previous owner, so I don't know all the details, but here is what I do know:

    -no A/C (never did have)
    -no aux pusher fan (possibly never did?)
    -clutch fan w/no shroud
    -not sure what rad or fan

    When I picked up the car it made good heat and the temp gauge read normal. Shortly thereafter it stopped making much heat and took a long time to warm up. Whatever, no big deal, I popped a new thermostat in it and full heat returned. I put in thermostat P/N W0133-1627833, which should be for a '96 328i (the donor car), ordered from here: http://www.autopartsway.com/AutoPart...=W0133-1627833
    The temp gauge now typically reads between say 60 and 70% when warmed up (on the high side of that spectrum when idling, on the low side at speed). We haven't had any really hot days here yet, but so far the temp readings are consistent, but high. Do I have the right thermostat? Is there some issue where the gauge reads high due to sensor differences for example? Do I simply need a fan shroud? This is what my rad looks like:

    #2
    I'd try putting a shroud on there and see what happens, since you should have one anyways. I'd recommend doing a water pump, too- sometimes the plastic impeller breaks but doesn't fail completely.
    '91 318is
    sigpic

    Comment


      #3
      WP was new at time of swap, but unfortunately they couldn't tell me whether they'd put in a plastic or metal impeller pump. Yeah, I'd like to put a shroud in... not sure where to start though--I think that is an E30 325 rad, but not sure what the fan is. Is there a stock shroud that will fit, or am I going to have to fab something up or modify a stock one?

      Doing a little more reading, and looks like the stock M52 t-stat is either 88 or 92 degrees, while the E30 stock ones are lower. I take this to mean that the E36 motors were designed to run with a higher coolant temp than E30, and thus the high gauge reading in the E30M52 is normal. I see a lot of swapped guys are running the cooler t-stats to 'fix' the high reading, but I don't see why? I am already running on the rich side, so I don't see the benefit from running lower than design temps.

      Comment


        #4
        the late model E30's share a radiator with the E36's. The stock E30 shroud should fit. If it were up to me, I'd put in a lower thermostat. Can you use a infrared thermometer to find the actual temperature at the thermostat housing? That would be better to compare it measured E36 coolant temperatures. My guess is that it is running hotter than it should, because the E30 chassis isn't as effecient at flowing air through the radiator as the E36 with larger underpanels, different front-end design, etc. 3/4 of the e30 gauge is a good amount of heat, especially up in Ontario.
        '89 325i track sloot
        '01 530i daily

        -Enginerd

        Comment


          #5
          Hmmm... That is interesting. Bear with me, I need to understand this...

          The steady state operating temp under a given set of conditions should be more or less at the thermostat opening temp, no? This means the thermostat cycles open and closed to maintain that temp, and the cooling system is not fully utilized unless the thermostat duty cycle reaches 100%. This still indicates to me that the E36 coolant temps are supposed to be higher than E30 by design. If the gauge reading moves after the car is warmed up, then I would think that is an indicator that the t-stat duty cycle has reached 100% and the cooling system is unable to reject enough heat to maintain a temp lower than the t-stat opening temp. So it seems to me that at that point it is preferable to improve the cooling system to a point where it can maintain a temp lower than the t-stat opening temp rather than lower that opening temperature no? Anyway, shroud is the first step I guess.

          Comment


            #6
            The T-stat doesn't cycle, it has some material in it that expands under higher temps, slowly opening the valve, letting more or less coolant flow. There is a spring on the T-stat that is compressed, pushing back against this expansion inside. At the rated temperature, the T-stat is at equilibrium, not moving. Engine gets hotter=more flow, colder=less flow. If the T-stat is rated too high for the application, it will not open enough to cool the engine to the normal level. If it is too cold, it will make it hard or impossible to fully warm the engine.

            The T-stat regulates the flow of the system, which effects how much heat the radiator can transfer to the air. The rest of the cooling system can be changed to increase efficiency, to the point that it can still extract enough heat at a lower rate of flow, but t-stats are cheap and easy.

            The shroud will aid in low-speed cooling, as will the auxilliary fan. A/C would lower the efficiency of the radiator, since it effectively blocks airflow and heats up the air that gets through, both of which lower the heat transfer potential of the radiator.

            Underpanels and the like aid in directing airflow through the radiator, and in essence create a high-pressure zone in front of the radiator and a low-pressure zone behind it in the engine bay (mechanical fan does this as well) Bigger pressure differential = more airflow = more heat out of the engine.

            If you know the normal operating temps for an e36, and compare them to your operating temps, you will know whether you are running hot or cold. If I remeber correctly, my roommate's E36 M3 (US) runs about 210* F, a little warmer than the average engine. If you are running around 230* F, you might want to adjust your aero (underpanel, etc) or internals (Water pump, T-stat) since this is the same temperature at low or high speeds. If you run at nearly 210* F (if that's correct), then you're fine, and the swapped E30 groups like to run their cars on the cool side for whatever reason.

            Did that help?
            '89 325i track sloot
            '01 530i daily

            -Enginerd

            Comment


              #7
              Yeah that makes sense. I was thinking of the t-stat as more of an on-off device, or with a smaller temp range between full open and full closed anyway. Where did you measure that temp?

              Comment


                #8
                This is makes sense to me. I'm running a PWR 40mm aluminum radiator, Stewart water pump, no mechanical fan, switched aux cooling fan. My engine runs more on the lean side, but runs at about 3/4 on the temp gauge. I'll probably borrow a temp gauge though to see what temp I'm actually running at.
                -Brandon
                '86 325es S50
                '12 VW GTI Autobahn DSG
                '03 540i M-Sport (sold)
                '08 Jeep SRT-8 (sold)

                For sale:
                S50 TMS chip for Schricks

                Comment

                Working...
                X