Tech Tip: Combat ‘Hot Spots’ with a New Flywheel – UnderhoodService

Tech Tip: Combat ‘Hot Spots’ with a New Flywheel

Here's the scenario: Your customer drops off her car for a clutch replacement. As a matter of course, you have the flywheel resurfaced prior to installing the new clutch; all seems well when the customer drives away. Later that month, the customer returns, complaining of clutch chatter. The assumption might be a defective or incorrectly installed clutch, but the culprit may be that resurfaced flywheel.

Here’s the scenario: Your customer drops off her car for a clutch replacement. As a matter of course, you have the flywheel resurfaced prior to installing the new clutch; all seems well when the customer drives away. Later that month, the customer returns, complaining of clutch chatter. The assumption might be a defective or incorrectly installed clutch, but the culprit may be that resurfaced flywheel.

"Hot spots" or hard spots on the flywheel commonly develop as the clutch nears the end of its service life, as more friction-generated heat is created when the clutch is engaged. That heat affects the flywheel, creating areas that are harder, more thermally stressed or warped.

Having the flywheel resurfaced may alleviate warping, but it doesn’t remove hot spots that are "baked" into it. Clutch chatter manifests itself when its friction material encounters the flywheel’s varied surface hardness rates, eventually creating high and low spots due to the different wear rate of the hot spots.

Severely hot-spotted flywheels cannot be machined to alleviate the condition; they must be replaced with a new one. Bottom line: Since resurfacing flywheels alone result in unwanted comebacks, it is critical to service the whole system. So, when installing a new ACDelco clutch kit, be sure to also install a new ACDelco flywheel.

ACDelco is a great resource for new flywheels, with about 120 part numbers that cover approximately 90 percent of the market for domestic and import vehicles.

Courtesy of ACDelco.

ACDelco markets quality parts for Ford, Chrysler, Toyota, Nissan, Honda, GM and most vehicles on the road today. To find an ACDelco parts retailer near you, visit www.acdelco.com or call 1-800-ACDelco.

You May Also Like

Alternator Testing For No Charge Conditions

Many alternator problems turn out to be nothing more than a bad connection at the alternator or a bad wiring harness.

If only battery voltage is present at the battery on a running engine, does this mean the alternator is “bad?” No, it does not. It only means that the alternator is not charging, but does not reveal why. Therefore, it does not point to a faulty alternator. All too often, the alternator is condemned by technicians due to this test alone. The cause could instead be a module that distributes the power to the vehicle and regulates the alternator.

Understanding Coolants

All-season coolant used inorganic acid technology and worked great for almost 30 years.

Ignition System Do’s and Don’ts

Why do ignition systems give technicians problems when diagnosing ignition-related misfires? The answer is that some technicians use tests that might give inconclusive results or do damage to the coil or drivers inside a module.

Tools To Service Serpentine Belts

Servicing the serpentine belt on some vehicles is a tough task.

Battery Charging and Diagnostics

Here are six tips to use when diagnosing a vehicle with a dead battery. 

Other Posts

Why Do Timing Chains Stretch?

As the timing chain wears, it can change the timing of the camshaft and crankshaft.

Carbon Deposits and Direct Injection Engines

The primary cause of these problems is that fuel and added detergents are not hitting the back of the intake valves.

Acura Turbo Engine Service

It is important to check the operation of the solenoids that control vacuum to the actuators.

Subaru EJ25 Head Gasket Problems

Most of the EJ head gasket failures occur around the 100,000-mile mark and start as a slow oil or coolant leak.