Hey guys,
I picked up my '89 325is last summer for $1000. Had a blown head gasket and needed a ton of work which was not a biggie for me. I have a fantastic mechanic working with me along the way who gives me a great break on labor.
My question is about a fluttery knock that happens mostly when the motor is cold. It is really noticeable when driving at higher RPM's. If I am at 3k in second gear it will start chattering. Change to 3rd and is subsides until I get the RPM's up again. Back off the gas a little--goes away. Hop on the gas--comes back again. I don't hear the sound when manually revving the throttle in neutral. I also can't hear it when the clutch is disengaged while driving the car. As the car warms up, the sound almost completely goes away. Since I am very familiar with this sound, I can tell that it is still present when the motor is warm so it really doesn't go away but it does quiet down considerably.
I have read through all the descriptions in previous postings and can't find anything that describes this sound. It really doesn't sound like rod knock or anything fatal like that. This is more of a flutter than a knock. Like if the distributor cap was getting in the way of the fan blades.
I got a call from my mechanic when he was reinstalling the rebuilt head and asked me if I wanted to replace the timing belt. He said that it looked really clean. I said no because the PO told me he had it replaced 5k before I bought it. Mechanic agreed.
Since we've gotten this car back on the road, the sound has been persistent. I have replaced:
Water Pump, PS Pump, Radiator, Thermo, ICV, All belts, All hoses, Alternator is clean-no noise, New Clutch kit, resurfaced flywheel, transmission seals, 2 valve adjustments also.
My mechanic can't hear it because he has become hard of hearing unfortunately. Could it be a valve? Something having to do with the timing belt? Thoughts or ideas would be greatly appreciated.
Adam
I picked up my '89 325is last summer for $1000. Had a blown head gasket and needed a ton of work which was not a biggie for me. I have a fantastic mechanic working with me along the way who gives me a great break on labor.
My question is about a fluttery knock that happens mostly when the motor is cold. It is really noticeable when driving at higher RPM's. If I am at 3k in second gear it will start chattering. Change to 3rd and is subsides until I get the RPM's up again. Back off the gas a little--goes away. Hop on the gas--comes back again. I don't hear the sound when manually revving the throttle in neutral. I also can't hear it when the clutch is disengaged while driving the car. As the car warms up, the sound almost completely goes away. Since I am very familiar with this sound, I can tell that it is still present when the motor is warm so it really doesn't go away but it does quiet down considerably.
I have read through all the descriptions in previous postings and can't find anything that describes this sound. It really doesn't sound like rod knock or anything fatal like that. This is more of a flutter than a knock. Like if the distributor cap was getting in the way of the fan blades.
I got a call from my mechanic when he was reinstalling the rebuilt head and asked me if I wanted to replace the timing belt. He said that it looked really clean. I said no because the PO told me he had it replaced 5k before I bought it. Mechanic agreed.
Since we've gotten this car back on the road, the sound has been persistent. I have replaced:
Water Pump, PS Pump, Radiator, Thermo, ICV, All belts, All hoses, Alternator is clean-no noise, New Clutch kit, resurfaced flywheel, transmission seals, 2 valve adjustments also.
My mechanic can't hear it because he has become hard of hearing unfortunately. Could it be a valve? Something having to do with the timing belt? Thoughts or ideas would be greatly appreciated.
Adam
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