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Rattle Between 2800-3000 RPMS

Man, this is driving me crazy. I have looked for the source of this rattle to no avail. It sounds like it is coming from the front of the passenger-side of the engine or exhaust. It sounds like maybe a heat shield, but I have checked them.

Anyone have any ideas?

You can feel the vibration also, but it feels like maybe 2 thin sheets of metal vibrating against each other. I have new motor mounts, new control arms, new steering rack and tie rods, but they are all tight.
Old 09-09-2010, 07:40 AM
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check the exhaust mounts.
There is a rubber mount up in the torque tube that looks like a pigs snout.
Make sure it's all the way in.
I've had the rubber get dislodged and make a terrible rattle at about the same RPM
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Old 09-09-2010, 08:03 AM
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There is a 2 bolt heat/dust sheild at the bottom/forward of the bell housing----Protects the FW.

GL
John
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Old 09-09-2010, 09:34 AM
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have you done your belts recently? lower b-s pulley off?
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Old 09-09-2010, 10:16 AM
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my car does the EXACT same thing. I thought I had checked everything. It sure does sounds like a heat sheild making the noise. I will check them again tonight and report back.

Thanks John!
Old 09-09-2010, 10:28 AM
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I did the belts on Saturday. I pulled everything off the front of the engine to replace the right gear carrier, but I that's not the problem. It was rattling before I did the job. Man, it gets so loud for a second that you can't barely hear the engine after about 2700 RPMs until it hits 3000 RPMs.
Old 09-09-2010, 11:10 AM
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Have you tried getting someone to hold the rpm so it makes the noise while you climb under and find it?
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Old 09-09-2010, 11:31 AM
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It's weird but it does not make the sound when the car is stationary. It seems to be louder when in gear moving forward.
Old 09-09-2010, 12:13 PM
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Holy Smokes! Have you had the front wheels off lately for one reason or the other? I recently replaced my dust shields with the new ones and torqued the bolts 2 lbs over spec. Right after that, At 2600-2800 RPM I got a rattle in the front that I couldn't identify. It was the new dust shields rattling because they were a little overtorqued. Now that was bizarre!
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Old 09-09-2010, 05:13 PM
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i'd double check your lover bs pulley because it is easy to put on wrong then it will be 180 out...if you just recently acquired the car, i'd definetly check and not rely on the PO's say-so. my PO for my car needed a good whack to the head.....idiot.
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Old 09-09-2010, 06:19 PM
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No, it's not the lower BS pulley. Lined up the marks myself Saturday. It's also not the dust shields either. I took them off last night, but it still has the rattle this morning. I am thinking maybe the exhaust somewhere. I will let you all know when I find it.

Thanks, you guys are great.
Old 09-10-2010, 04:43 AM
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It is the upper heat shield on the front of the exhaust. It isn't loose, but what is happening is the upper rear end of the shield is reaching a harmonic at that rpm and hitting the header. At least that was what was happening with my car. It was so loud, that was all I could hear at that rpm range. I just bent the shield away from the exhaust and the rattle went away.
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Old 09-10-2010, 09:22 AM
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No to resurrect a thread, but did anybody ever figure this out? I recently restored a 944 and there is a rattle at this exact range.

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Old 11-01-2017, 07:51 PM
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climb under the car and take a good look at the exhaust and how close it is to the body/heat shields/etc.

find the spot where it is closest to touching, loosen the exhaust hanger u-bolts and shift the system a little further away, tighten and re-check.

my replacement cat was rubbing on the front body heat shield like this.
Old 11-02-2017, 08:08 AM
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Quote:
Originally Posted by John_AZ View Post
There is a 2 bolt heat/dust sheild at the bottom/forward of the bell housing----Protects the FW.

GL
John
Not sure what a FW is, and may be the same but I had a similar rattle and it was the heat shield for the oil level sensor on my S2. It is cantilevered pretty far out from the mounting flange, and was cracked completely through one mounting hole, and partially through the rear. It was singing at idle through 3K RPM. I think bad motor mounts may have hastened its failure.
Old 11-02-2017, 10:01 AM
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Don't forget to check for a loose O2 sensor, been there, done that
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Old 11-02-2017, 02:54 PM
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I don't have the oil level sensor, though it's an 87 and has the wire, i think the previous owner swapped pans. I'll check the other areas

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Old 11-04-2017, 06:13 AM
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