As your Toyota Supra gets a bit older, it is not uncommon for the crankshaft pulley (harmonic dampener) to develop hairline cracks.

Does your Mk4 Toyota Supra squeal like a pig when you start it or rev the engine? Could it be the fan belt slipping? As you've found this page, I thought you might be interested to read about the Crank Pulley on my Mk4 Non-Turbo Toyota Supra.

From Supra Enthusiast: My Supra was showing the usual signs of the fan belt slipping. It made a squeal when it was first started up, and a slight screech when blipping the accelerator. It also made a funny squeaking screechy noise when maneuvering or when the engine was laboring. More so when steering as the power steering pump put more load through the belt.

The problem turned out to be the Crank Pulley, NOT the fan belt. This is the wheel on the end of the crank that turns the fan belt, in case you didn't know. :-)

The stock Toyota crank pulleys are made of more than one part separated by a rubber damper designed to protect the crank from vibration and wear. When the crank pulley gets old, the rubber wears and the two parts slip, causing the squealing noise. If you don't replace it, it could fly off and smash up other bits in the engine bay.

Prove this is the problem by painting a line of tipp-ex across the two parts, then rev the engine and check to see if the tipp-ex marks still line up. You can reach down to get to it, through the gap marked with the arrow in the picture. Even after simply starting the engine on my Supra, the two parts had slipped and the tipp-ex marks didn't line up any more.

After the old pulley was removed, it turned out to be so worn, the outer wheel was literally flopping about on the inner one!

If your Toyota Supra harmonic dampener (crankshaft pulley) is older than 15 years (and it most likely is), you should consider replacing it. This is a genuine original Toyota part and is always in stock.

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