Knocking and rattling in Elizabeth's older car: just like mine!

exhaustsystems

#1

One caller on the June 14 broadcast had a loud high speed knocking and intense engine sound that was louder inside the car than outside. My '92 Jetta, Midge, has been sucking a trickle (on average) of money from my wallet for the exact same symptoms for several years. (I’m too cheap to junk it.)



The soul jarring engine roar that I thought would permeate my being and alter my brainwaves turned out to be a cracked exhaust manifold. In addition to the mind altering sound, the exhaust wafting up into the cab when the car wasn’t moving (traffic jams) wasn’t great for the brain cells either. The cracked manifold was apparently contributing to the other noise but more on that in a bit. A little whoops necessitated a new exhaust system all the way to the manifold. However, the new exhaust wasn’t built to fit to the old manifold and (per my new mechanic) contributed to the demise of the manifold. Unfortunately, new manifolds aren’t made to attach to my old engine, hence why my old mechanic stopped the replacement frenzy where he did. The new manifold required a labor intensive retrofit that significantly contributed to the financial security of my new mechanic.



The machine gun-like sound coming from under the car was the exhaust pipe sitting on the frame and rattling against it with the vibration from the engine and started shortly after that new exhaust system I mentioned above was installed by my old mechanic. Incidentally, the rattle usually stopped or significantly lessened above 4,000 rpm so driving over 83mph on the interstate was much less stressful than the legal 75. The reason the exhaust pipe was sitting on the frame is because the thick rubber hangers that hold it up away from the frame in several spots all broke. The problem I’ve had is that new ones never lasted for more than about 100 miles. Replacing the exhaust manifold apparently relieved some of the stress on these chunky little things but they still only last a few months before the impact driver concert returns. A set of hangers costs only $10-15 and are reasonably easy to replace but it gets pretty old even at the new slower pace of 2-3 time a year. After the most recent return of the rattle I replaced my ancient 5 month old broken hangers with homemade loops of #4 copper wire left over from a home electrical project. Since it is nearly impossible to craft loops of exactly the right size I now have a much quieter metallic sizzle sound from one of the loops that is just a little too big and jiggling around as I drive. If this lasts at least a year I’ll squeal for joy and invest in some of that liquid rubber that you dip your old tools in to rubberize the handles. Hopefully that will muffle the tinkerbellish buzz that I now endure. At least I can hear the radio now. However, the higher pitched sound is now louder outside than inside so pedestrians tend to watch me drive by in sadistic hope of seeing my car deconstruct and spread out over the road right before their eyes.



I think the missing door trim and ever-so-slightly crumpled hood adds to the effect! (c: