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The mkiv Supra Owners Club

Squeal diagnosis


Ewen

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I've had a squeal a couple of times when starting the car after a night of damp / raining...the squeal is in time with revs, and goes away once engines warm.

Im sure its not a slipping belt.

The first time it happened I lifted the bonnet but could not tell for sure where it was coming from. Starting the car later that day, the noise had gone. I've had a couple of similar episodes since.

This morning it did the same, then got rather loud, and I pulled over.....lifted the bonnet with engine running and as I tried to suss where it was coming from, it stopped making any noise at all. It was ok rest of way to work, looked fine when I lifted the bonnet, and seemed fine on the way home tonight.

Ive read that it could be either crank pulley / tensioner / power steering pump / belt etc but how can I tell whats actually making the noise if I cant tell where its coming from ? Whats the likeliest culprit from description above ?

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Worse case I expect is the crank pulley, a few tests for you:

 

- When the car ios cold, start it up, then reverse slowly and put on full lock. This loads up the engine and the PAS and in thoery cause the crank pulley to squeel if it's a fault

- Get something like a crank bar and gently try and momve the outer ring of the crank pulley away from the engine, if there is move than a fraction of movement from the outer ring, this could be a sign of failure

- While the engine is running (and cold), look down at the crank pulley from directly above it, blip the throttle and see if the outer ring is moving forwards/wobbling.

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Ewen, whats your cambelt change history.....

 

with your low mileage/new car i would suspect the crank pulley above other bits (assuming the belts fine). Crank pulleys can be heated to failure, all the other parts will be worn out by mileage/ageing imo......

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I had this and ended up with a new cam belt tensioner, new aux belt and tensioner and new crank pulley.

Cheers Martin, Lets hope its just one of them for me:)

Worse case I expect is the crank pulley, a few tests for you:....

Thanks Homer, will try this tomorrow.

Ewen, whats your cambelt change history.....

with your low mileage/new car i would suspect the crank pulley above other bits (assuming the belts fine).....

Hi Scott, cambelt changed at 8,000 miles on odo, 26,000 miles ago.

Crank pulley No. 1 suspect so far then.

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Worse case I expect is the crank pulley, a few tests for you:

 

- When the car ios cold, start it up, then reverse slowly and put on full lock. This loads up the engine and the PAS and in thoery cause the crank pulley to squeel if it's a fault

- Get something like a crank bar and gently try and momve the outer ring of the crank pulley away from the engine, if there is move than a fraction of movement from the outer ring, this could be a sign of failure

- While the engine is running (and cold), look down at the crank pulley from directly above it, blip the throttle and see if the outer ring is moving forwards/wobbling.

 

Before doing this, simply put a line of tipex over the inner to outer bit. Makes it 1000 times easier to see if they have moved and split.

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The car had a slight squeal this again this morning. Looked at the crank pulley...to a guy like me it looks ok when doing what Homer suggested. I actually now think its coming from the power steering pump but cant be sure. The sound is faint and depending where you stick your head, the noise is either coming from the steering pump or throttle body area.

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Hi Ewen,

 

Mine did this and Chris Wilson diagnosed it as the crank dampener (pully - same thing?) which had disintegrated in the bottom of my undertray! Sure enough, £187.00 later for the part + labour and the problem was fixed :)

 

Good luck.

 

Greg

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