 Tracking Down Alarming Noise, Two months of agony |
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| Osnabruck914 |
 Jul 8 2025, 12:15 PM
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#1
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Member  Group: Members Posts: 151 Joined: 19-December 22 From: United States Member No.: 27,038 Region Association: South East States  |
Two months ago, out of the blue, my '74 2.0 suddenly started making an alarming clunk and rattle on startup and acceleration. After complete warmup the sound diminished but was always still there but never affected performance.
I started my investigation by getting under and over the car, tightening every possible screw and bolt that could be loose- transmission mounts, engine bar mounts, engine tin, starter bolts, etc., etc. No luck. I was starting to have nightmares thinking it was something deeper inside the engine. Took the car twice to my local 914 guy, who spent a lot of time looking for the source of the noise. He was baffled, but assured me he thought it was nothing serious and that I would find it eventually and he was right. I finally decided to remove every heater component on the driver side to start ruling things out- that did nothing. but when I removed the passenger side heater components presto- no noise! When I put it all back together, the noise came back, but at least I was sure it was one of those passenger side heater pieces. Results - Found the passenger side warm-air elbow (see pics) that connects the heat exchanger to the heater valve box was bouncing and rubbing on the engine bar- that was the annoying and alarming noise I was hearing. After properly tightening and positioning that elbow all is normal and I can sleep soundly again. As a bonus, the car is extra smooth and quiet now, as everything possibly loose and rattley has been tightened (IMG:style_emoticons/default/smile.gif) Osnabruck914   |
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| rjames |
Jul 8 2025, 12:42 PM
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#2
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I'm made of metal Group: Members Posts: 4,327 Joined: 24-July 05 From: Shoreline, WA Member No.: 4,467 Region Association: Pacific Northwest 
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Congrats on figuring it out.
If my car didn't rattle I'd assume something was wrong. (IMG:style_emoticons/default/laugh.gif) |
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| jim_hoyland |
Jul 8 2025, 07:38 PM
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#3
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Get that VIN ? Group: Members Posts: 9,828 Joined: 1-May 03 From: Sunset Beach, CA Member No.: 643 Region Association: Southern California
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Nice going long time ago I had a control valve come loose and felll to the pavement. The heater cable was still attached; what a racket!!!!
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| wonkipop |
Jul 9 2025, 03:01 AM
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#4
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Advanced Member Group: Members Posts: 4,854 Joined: 6-May 20 From: north antarctica Member No.: 24,231 Region Association: NineFourteenerVille
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excellent work.
don't you just hate rattles. and then don't you just love the feeling after you smash the problem. (IMG:style_emoticons/default/beerchug.gif) (IMG:style_emoticons/default/beerchug.gif) (IMG:style_emoticons/default/beer.gif) |
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| Osnabruck914 |
Jul 9 2025, 09:54 AM
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#5
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Member Group: Members Posts: 151 Joined: 19-December 22 From: United States Member No.: 27,038 Region Association: South East States |
QUOTE(wonkipop @ Jul 9 2025, 05:01 AM)  excellent work. don't you just hate rattles. and then don't you just love the feeling after you smash the problem. (IMG:style_emoticons/default/beerchug.gif) (IMG:style_emoticons/default/beerchug.gif) (IMG:style_emoticons/default/beer.gif) Absolutely! Even the slightest clunk or rattle totally ruins the driving experience, at least for me. Osnabruck914 |
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| dr914@autoatlanta.com |
Jul 9 2025, 10:05 AM
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#6
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914 Guru Group: Members Posts: 8,188 Joined: 3-January 07 From: atlanta georgia Member No.: 7,418 Region Association: None |
typical
QUOTE(Osnabruck914 @ Jul 8 2025, 11:15 AM) Two months ago, out of the blue, my '74 2.0 suddenly started making an alarming clunk and rattle on startup and acceleration. After complete warmup the sound diminished but was always still there but never affected performance. I started my investigation by getting under and over the car, tightening every possible screw and bolt that could be loose- transmission mounts, engine bar mounts, engine tin, starter bolts, etc., etc. No luck. I was starting to have nightmares thinking it was something deeper inside the engine. Took the car twice to my local 914 guy, who spent a lot of time looking for the source of the noise. He was baffled, but assured me he thought it was nothing serious and that I would find it eventually and he was right. I finally decided to remove every heater component on the driver side to start ruling things out- that did nothing. but when I removed the passenger side heater components presto- no noise! When I put it all back together, the noise came back, but at least I was sure it was one of those passenger side heater pieces. Results - Found the passenger side warm-air elbow (see pics) that connects the heat exchanger to the heater valve box was bouncing and rubbing on the engine bar- that was the annoying and alarming noise I was hearing. After properly tightening and positioning that elbow all is normal and I can sleep soundly again. As a bonus, the car is extra smooth and quiet now, as everything possibly loose and rattley has been tightened (IMG:style_emoticons/default/smile.gif) Osnabruck914 |
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| Root_Werks |
Jul 9 2025, 10:24 AM
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#7
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Village Idiot Group: Members Posts: 8,745 Joined: 25-May 04 From: About 5NM from Canada Member No.: 2,105 Region Association: Pacific Northwest
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Good sleuthing! Rattles or thumps and bumps never good.
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