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E30 325 Hints- loose elbow, worn sensor wire, & 'black hole'

     
     Three items to watch out for in your E30 325:
     
     
     1. Press-fit elbow coming loose at the thermostat housing area. 
     
     Just recently, I serviced the cooling system (new hoses, thermostat, 
     and coolant) in my '90 325iX. As I was pulling off the small hose that 
     runs from the thermostat housing to the throttle body, I noticed that 
     this hose was moving the elbow (about 1/4" ID) that is a press fit 
     into the thermostat housing on the cylinder head. The original owner 
     had mentioned a problem in this area, when I asked about the bailing 
     wire tied around the thermostat cover area. This elbow had popped-out 
     a few years ago and was 'permatex'd' back-in by the original owner 
     (his wording). The wire was in place as a backup. The BMW dealer where 
     I purchased my used '90 325iX, said that there was 'no coolant system 
     problem' in that area (they just snipped off the wire and looked for 
     leaks). The whole area was fairly encrusted with green dried 
     antifreeze.
        The fix - I cleaned-up the original 'goop' fix from both the elbow 
     and bore in the head with solvent and emery paper. I was lucky that 
     there was no corrosion. I roughened up both surfaces (to give 'tooth' 
     for the epoxy to come) with very corse sandpaper. To make a slightly 
     tighter fit (you could seat the elbow with just finger pressure), a 
     center punch was used to put dimples on the male surface of the elbow. 
     This made for more of an interference fit. And finally, a medium time 
     curing epoxy was used to totally seal and bond the elbow in place. An 
     aluminum filled epoxy would have been better (definetly avoid 
     '5-minute' class epoxies for any repair involving water contact).
        The next time you E30 owners are working around the thermostat 
     area, give that elbow a yank to see if it's tight. If it comes out or 
     rotates, you have potential quarter-inch hole in your cooling system. 
     The result could be more serious than lost coolant...
     
     
     2. Rubbing Engine Reference Sensor
     
     During the above mentioned coolant system maintenance, I also replaced 
     the engine reference sensor (the combination engine speed & TDC 
     pick-up that reads off the toothed ring on the front of the engine). 
     Mine had worn thru the outer insulation (no big deal) and about 80% 
     thru one of the two conductors (timebomb). It seems the last person to 
     change out the timing belt, failed to route the sensor thru the two 
     little clips (and/or broke them) that keep the sensor wiring harness 
     from rubbing on the waterpump pulley. 
        There are two little plastic clips that fasten to the front of the 
     timing cover. The clips are a little on the lame side. The clips also 
     hold another cable (engine oil level I believe?) away from the pulley. 
     And incorrectly in my instance, the spark-plug tach lead. The correct 
     route for the tach wire (senses off the sparkplug lead) is over the 
     distributor, instead of under. 
        I rerouted my sensor cable to not even go thru the little plastic 
     clips. I routed it along the metal radiator hose pipe and used cable 
     ties to fasten. 
        Check those plastic clips. They're cheap (under $2). Your engine 
     won't run if the engine reference cable gets sawed thru. Actually, the 
     motor will run (according to a trained BMW mechanic), but it won't 
     restart if the sensor wires gets cut.
     
     
     3. Missing timing belt cover.
      
     The same 'mechanic' that caused the above sensor wire problem, 
     probably caused this one too. There is a rubber cover that just snaps 
     over the front of the cast aluminum timing belt housing. This cover is 
     on the left side of the engine (intake side) and protects the timing 
     belt from the elements. Mine was missing. The $12 (US) part is fairly 
     easy to install. Just make sure it snaps over the front portion of the 
     cover housing. With the cover missing, you're probably taking more of 
     a chance in creating a potential 'black hole' for dropped nuts and 
     bolts (None of the fasteners that I ever drop in the engine bay ever 
     hit the ground. Where do they go?) than a problem with keeping out 
     dust and water. 
     
        Barry Ritchey
        CCA#-134069
        '90 325iX