...continued Many exhaust systems have stainless-steel, sheet-metal heat shields surrounding the catalytic converter. Eventually, motor mount problems may create rattles by shaking these heat shields loose.
Bad mounts often allow the enging to pull hoses taunt, causing premature or repeated coolant or refrigerant hose failures. Usually, cracked metal tubing or fittings at the air conditioning compressor are a telltale sign of severe engine shake.
When enging compartments were roomier and refrigerant was inexpensive, hose failure was much less of an issue than it is now. but changing a damaged coolant or refrigerant hose inside today's crowded engine bays often is a tedious, lavor-intensive task. and considering the exorgitant cost of refrigerant, losing the refirgerand charge over a faulty motor mount is a costly, unpleasant lesson for both motorists the technicians. It's double painful when the customer has already invested heavily in air condition work at your shop and a bad motor mount causes a new leak in a recently repaired air conditioner!
Exterme engine movement may allow refirgerant hoses to rub against inner body panels or other underhood parts. This may cause annoying bussing or moaning noises or vibrations that only occur during air conditioner operation.
Motor mount troubl ecan stress or bind up cluth linkage, causing the driver or an uniformed technician to suspect clutch or transmissin problems.
When fatigued or broken mounts allow the powertrain to sag or shift from its original location, it alters the drive axles' operating angle. this may bind up the inner constant velocity (CV) joints, producind the familiar clunking/thumping noises and vibration or shuddering. Left uncorrected, a binding CV may damage a transaxle driveshaft seal, creating a transaxle fluid elak. a binding CV can also cause premature bushing or bearing wear inside a transaxled.
Ususally, binding inner CVs are very sensitive to changes in engine load. Some CVs vegin shuddering druing brisk acceleration, others vibrate or cause a slight shimmy only during light acceleration or when changing lanes.
Occasionally, a combination of sudden accereration followed by abrupt deceleration is the quickest way to detect a dinding inner CV joint.
Plus, a sagging or mispositioned powertrain can increase the operating angle of the driveshaft enough to create a load the speed-sensitive vibration or shudder on rear-drive vehicles.
Never blame a shudder or vibration problem on inner CV joint or driveshaft universal joints until you have thoroughly inspected the motor mounts first.
Finally, bad motor mounts may create or aggravate hesitation or stalling problems on vehicles equipped with air flow sensors. On most air flow sensor-equipped engines, an air duct or tube connects the air flow sensor to the engine's intake throttle housing. A combination of are, underhood heat, and normal engine vibration my cause the intake air duct to crack. But abnorman enging shake due to worn or borken mounts only increases the likelihood of a cracked or loosened air duct.
When the engine draws extra, unwanted air through a cracked duct, the air/fuel mixture goeal elan and the engine hesitates or stalls. Sometimes, the engine only stalls in reverse because shifting the vehice into reverse jogs he engine enough to open up the crack in the air duct!
Small crack in an air-sensor-to-engine air duct may be difficult to dectect. In a darkened room some techs disconnect on ent of the duct, shine a bright work light in and look for rays of light "leaking" out.
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