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Harmonic Balancer failure @ 70K miles


Reatta Man

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My Reatta started making a knocking noise in the front area of the engine. I couldn't tell what component it was since they are all connected to the block and transmit the noise of one component through nearly all of them. <P>Turns out that the rubber donut inside the harmonic balancer failed suddenly at 70K miles with no warning. This part is one of the few weak links in the 3.8 engine and was very poorly designed. When it goes, it is not comforting because it is a loud metal-on-metal sound that can easily be mistaken for a damaged timing sproket or a rod knock. <P>If you hear this sound, a good way to diagnose it is to remove the serpentine belt. If it only makes the noise with the belt in place, it is likely the balancer. I didn't catch this quickly on another 3.8 Buick engine I owned and it WILL allow the crankshaft to go enough out of balance to eat the main bearings. <P>Replacements are about $100 after market and much more at a dealer. So far, it's taken me about 2-3 hours to get the old one out. The new one goes in tonight after work. <P>Joe

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Just a little something to keep in mind. Some parts don't fail due to milage, but rather age. The rubber in the harmonic balancer will deteriorate over time, just like serpentine belts & radiator hoses.<P>Suggestion for checking the H/B - you can do so without removing the belt. Just run your fingers around the rubber center part to check how deteriorate the rubber is, and then decide if you want to replace it now, or wait for an untimely failure.

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Another way to see if the balancer is slipping. Grab the alternator fan (without the engine running) and rotate it bach and forth. If the balancer is bad you'll see the belt side of the balancer slipping without moving the inside a few inches. <P>My other buick the balancer failed on my vacation in Oklahoma. I found the part at the dealer for an out of town price. The dealer wanted something like 4 hours to put it on. I said "4 hours! That's not what it said in you labor guid. Why should it take you 4 hours. All you have to do is slip the belt loose, remove 1 bolt, and it slides off without a puller." He told me "we know how to do it". I told him "not if it takes you 4 hours".<P>I replaced it in a parking lot in 15 minuits with a few hand tools. <P>One last trick on how to remove the balancer bolt without a inpact tool. Put the socket on the crank with a rachet or breaker bar perferibly 1/2" drive. Wedge the socket wrench against something on the right side in this case the engine cradle. Make shure nothing is going to get squished under the socket wrinch like wires, plastic, lines, etc.. Tap the key to start quickly. You'll hear a pop and the bolt will be loose. To put back on just hit the socket wrinch with a hammer until tight. <P>Double check to make sure the crank sencer rings dont hit the crank sencer. Put a little oil where the seal rides. You may even put a small amount of RTV on the washer side of the balancer bolt and where the balancer goes on the crank. This helps to keep any oil the ever makes it thru the balancer keway from getting on the outside of the engine. <P>Tom

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All,<P>I thought I was keeping an eye on it since the one on my other Reatta failed. It split suddenly where the rubber meets the outside pully that touches the serpentine belt. <P>You're right, the south Texas heat probably did it in more than the mileage. <P>Joe

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Barney,<P>If all goes well, while most of San Antonio is downtown getting drunk and sunburned at the Fiesta parade this afternoon, I will finish getting the balancer installed. <P>If you see a red coupe running down Hwy 306 going toward Canyon Lake Saturday, that will be me driving my newly-repaired computer-on-wheels, AKA the Reatta. <P>Come by Hill Country Resort if you are near Canyon Lake and look for my car in the parking lot. If its there, come in and I'll buy you a glass of iced tea. <P>For all of you not lucky enough to live in South Texas, this time of year has to be seen to be believed!! What a beautiful place to enjoy a Reatta.<P>God Bless Texas! GO SPURS GO!<P>Joe cool.gif" border="0

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  • 3 weeks later...
  • 2 months later...

Good Morning to All,<P>I have an 1989 Reatta, with 169000 miles on it, that has an engine knock which started yesterday at idle at a traffic light. I thought it was the either the water pump bearing or the AC compressor clutch. Turns out that after replacing the water pump, the knocking sound is still there. <P>My questions is this, it sounds like that it may be the harmonic balancer, but the engine noise "goes away" after revving the engine slowly upward a couple of hundred RPM. Does this characteristic follow with any other Reatta owners that had a harmonic balancer failure??<P>I tried using a sounding rod to all components on the serpentine belt side of the engine (where the noise is coming from) and all sound fine, (i.e., power steering, AC compressor, water pump, etc.)<P>Any advice would be very much appreciated. By the way, engine oil level verified to be full.<P>To reiterate, the engine noise goes away when load is added to the engine and is evident when the engine is at idle speed. confused.gif" border="0

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....Homebaron....read Tom's post about turning the fins on the alternator pully. Or you can pull on each side of the belt and note that the big hex nut on the balencer pully isn't moving while the other pulleys are. There's a pin which lodges against the rotation every 360 deg. The osillations of the motor while idling cause a hair raising "clang, clang". A slight press on the accelerator loads the pulley against the pin and the noise goes away until you're back in idle. i like Tom's idea of putting a socket on the big bolt and bumping the starter...but be careful and stingy with the key! With a lift and impact wrench it can be done in...say about 45 secs....if you don't have to pry or smack the old pulley off with the handle of your socket wrench....then a minute and a half.>>>>>>>>>>>?

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and don't forget a long 18 mm box end to relieve the tension on the belt.<P>BTW the breaker bar and crank really works but I usually wrap the bar with a bungee cord and strap to the "immobile object" (crossmember on a Pontiac 400). If there is any way the handle can snap against the radiator or other delicate object, it will so pad the area. If you must use an extension, use the shortest one you can find.<P>I do not use a 3/8 ratchet to do this, is a lot of force involved, only a 1/2" breaker. Further I make sure the breaker is pre-loaded and not just loose on the bolt head.<P>In addition, I pull the ignition module connector (used to pull the coil wire. Modern times) first so there is no way it can fire when the starter is just nudged. A nudge is all it takes as it just needs to be loosened a little. If the first nudge does not work, I always make certain the socket is fully seated and preloaded before applying a second nudge.<P>Caveat y'all - this is no an approved method by any sanctioning body, it can be downright dangerous to both your health and the bodywork however it has worked for me a few times.<P>Of course now you have the problem of holding the crank still while tightening the new one. The official method is to pull the torque converter cover (easy) and lock the flywheel. Installing the serpentine belt and wedging it will put a lot of shear on the rubber in the balancer and you really do not want to do that.<p>[ 08-04-2001: Message edited by: padgett ]

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Thanks for your replies, balancer has been replaced! Entire rubber area of old balancer let loose from pulley. <P>After installation of new balancer, noticed that the vibration dampening bracket is riding directly upon the balancer. Unfortunately, I had to 'move' the bracket away from the pulley and 1/8" or so. <P>Replaced crank sensor along with balancer. Total parts cost from NAPA ($199.00)<P>Thanks Again,<P>Dan rolleyes.gif" border="0

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My A/C clutch locked up last week. After I replaced the compressor it still had a noise. I knew what the noise was. The old compressor broke the harmonic balancer. Maybe I should have not tried to drive it home but I had too much pride to call a tow truck. <P>After that was done it had another noise. The small mount bracket was rubbing on the new GM balancer. I thought I was going crazy until I just read someone elce had the same problem. I guess I could bend the bracket up a bit so it does not rub. But why? I went to take it off and ended up snapping off the end of the mini shock looking thing. I just left it off for now and I'll worry about it another day.<P>Tom

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