Guest Recian Posted December 17, 2011 Share Posted December 17, 2011 Well I finally brought my 89 home today after the 6 month overhaul. It ran very very good. I noticed driving in town occasionally when at a stop i get a very aggressive vibration. It doesnt change if I put it in Park or Neutral or rev it up. When at idle it's 750. 650 when in drive. It idles so smooth the engine feels like it's not running so when this vibration kicks in i definately notice it. The RPMs dont change when it happens. Im thinking harmonic balancer is starting to go bad. Any ideas? Link to comment Share on other sites More sharing options...
padgett Posted December 17, 2011 Share Posted December 17, 2011 "It doesnt change if I ... rev it up" - no change with engine speed ? Blower fan maybe ? Link to comment Share on other sites More sharing options...
Guest Recian Posted December 17, 2011 Share Posted December 17, 2011 a/c blower? i have the climate control off since i dont have a condensor and it's been in the 70s here. I thought cooling fans maybe pulling a load since it happens when temp is over 205 usually but i cant hear the fans Link to comment Share on other sites More sharing options...
2seater Posted December 17, 2011 Share Posted December 17, 2011 Is this possibly related to the odd "wobbles" of the crankshaft or has that been resolved? I would think rpm would have an effect if so. What condition are the mounts and exhaust hangers? Metal to metal contact will transmit all sorts of odd sounds or feelings. I tried a solid upper torque strut mount but it was intolerable. Link to comment Share on other sites More sharing options...
padgett Posted December 17, 2011 Share Posted December 17, 2011 Sine the exhaust gas issue back in the 60s, the blower fan in a GM car always is on at least its lowest speed. (Unless you unplugged it) Link to comment Share on other sites More sharing options...
Guest Recian Posted December 17, 2011 Share Posted December 17, 2011 i have all new motor mounts. the crank movement turns out to be normal movement if padgett is right. He posted before that some movement is acceptable since the crank walks forwards and backwads as it rotates but there is a spec for movement. I know it's not bent since the torque converter seal isnt leaking. Also if there was something out of balance i'd assume it would do it all the time not just when it feels like it and when the car's temp rises over 200. My exhaust hangers are fine. It's not a metallic sound just a dull vibration. It does feel like similar to a solid motor mount. I put some in my hyundai once and i couldnt stand to let out the clutch due to the vibration. It's very similar to that Link to comment Share on other sites More sharing options...
Guest WEB 38 Posted December 17, 2011 Share Posted December 17, 2011 I had a similar problem years ago, It was a thermostat vibrating, I think that might be your problem. Bill Link to comment Share on other sites More sharing options...
padgett Posted December 17, 2011 Share Posted December 17, 2011 2Seater is right, a bad motor mount can feel like the engine is falling out. OTOH the "over 205" and no relation to rpm sounds a lot like a radiator fan that has lost a blade. You can go into overrides ES07 and ES08 with the key on and engine off to turn on the pusher and puller fans. Link to comment Share on other sites More sharing options...
Guest Recian Posted December 17, 2011 Share Posted December 17, 2011 it would make sense but dont the fans not even come on til 220? i havent had the car to 220 yet. It hasnt gone that high since the rebuild Link to comment Share on other sites More sharing options...
Ronnie Posted December 17, 2011 Share Posted December 17, 2011 it would make sense but dont the fans not even come on til 220? i havent had the car to 220 yet. It hasnt gone that high since the rebuildInstead of debating the hows and whys of it being a cooling fan, it would make more sense to just go into diagnostics and turn on each fan, one at a time, using overrides ES07 and ES08 as Padgett suggested. It shouldn't take over three minutes to do the test. If you feel the vibration start when the fan starts you know for sure that's what's causing it. Link to comment Share on other sites More sharing options...
2seater Posted December 17, 2011 Share Posted December 17, 2011 Who knows if the fan calibration is off? Easy to check visually for damage also. I have had the front fan lose a blade and it vibrates, badly. Link to comment Share on other sites More sharing options...
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