Karl_W944

There are two sounds going on with my '84.
1. This pitter patter sound only happens on cold starts, and goes away after a minute or two. Sounds like knock.
2. The second sound is constant and never goes away. It's a sqealing sound that doesn't change in pitch, but in frequency with throttle inputs as seen in my video. I think it's the alternator, the pulley, or the belt?
https://www.youtube.com/watch?v=D6qYaoqGjDM#t=50
Any ideas?

odonnell

The lower pitched 'knocking' sounds like a noisy belt drive, so maybe a idler or tensioner pulley for the balance shaft belt or timing belt. My car makes a less dramatic version of that noise you can only hear when the hood is up. The higher pitched noise definitely sounds like acc belt noise. Put on some belt dressing and see if it goes away. If so, you found the source.

Spidey944

Or take off the drive belts and start the car, it will run on battery power only so dont run it too long, but this will help you determine if it's an internal/engine noise, or an accessory component noise.

EDIT: after listening again, sounds like maybe a timing belt idler bearing. The slapping noise might be something hitting the timing cover.

Karl_W944

I've dressed the belt, the squealing sound hasn't gone away. And I've now noticed that the slapping/knocking sound even when the car is warm.

odurandina

sounds like a week after it was time to sell the engine?

(maybe, cuz you ain't losing coolant), it's a seized up idler pully.


,

odonnell

I would take off the timing belt cover and make sure the belts are in good health and nothing is slapping like Spidey said. I would feel the timing belt and make sure it isn't dumb-*** loose and thwacking against the water pump guard.

Karl_W944

I'm assuming this kind of stuff will have to wait until I can find someone who can help and walk me through this stuff in person.

Dougs951S

Its really easy Karl and you should learn to work on your car by yourself, this is a good forray into it. All you are doing is removing the belt guards and making some simple observations. This is step one to diagnosing any issue so consider this practice for when something really does go wrong. It will give you a chance to observe the belt drive and see how it all works.

Karl_W944

I'll give it a go then. How's the belt cover attached to the engine? Screws, or something else? I'll run the engine without the cover to see if the sound goes away.

Does it require me to raise the front end?

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Dougs951S

Karl, I'm confident that if you open the hood and actually look at the belt covers, you'll be able to figure out how it comes apart The car does not have to be in the air, but you will have to remove the air box and snorkel.

Not trying to be mean, trying to encourage you. I'll give you a hint, the bolts are 10mm. I wont tell you how many there are though, make sure you get them all before you try to pull the cover so you dont snap it!

austin944

What's that "chuffing" sound? It seemed to get louder when you got under the car. Minor exhaust leak?

Compare the sound from this car, which has no chuffing sound:

Karl_W944

I discovered the sound, the squeal is not from the alternator at all. It's coming from the power steering pulley or belt, in the middle. I accidentally got some belt conditioner spray on the pulley, and the sound got much much louder as I found out.

I've begun to remove the airbox and MAF, but I can't get it out completely.


(The second clamp to this random snorkel fell into the engine bay)

I'm not sure which of these last things I need to remove:

austin944

On my '84 NA, I've never needed to touch the airbox or the AFM to remove the upper timing belt cover. Just remove the bolts to the cover and slide it out; it may help to remove the power steering belt. Clark's Garage mentions removing the airbox and the AFM as a unit, but I've never done that even when changing the belts. That procedure may be for a different car like a Turbo or S2.

Karl_W944

I simply removed the elbow joint connected to the throttle body and left the MAF/AFM abd airbox together as a unit. I couldn't completely remove it so I ended up pushing it up and away to get underneath. But I could only remove a single bolt from the cover; none of my wrenches or sprockets could get the others; then again, I'm using non-metric tools on a German car, so I kinda got what I deserved on that one.

Oh, and then I pulled the center hose connected to the motor, only to realize last minute that it was the coolant hose and spilled a little but not too much to cause panic.

I'll have to get a metric tool kit from Harbor Freight this week and some other things, but at least I know I can get some big things out of the way if need be. Everything is back together for now.

Also, I checked around for the tapping sound, the frequency of the taps goes up relative to the amounts of revs, And it sounded like it wasn't coming from inside the timing belt cover at all. It seemed closer to the cam tower, which leads me to wonder if it's possible it could be valve chatter?

austin944

I don't recommend excessive prying or pushing in that area since you may wind up breaking something. Better to get everything disconnected properly and leave the pushing to sturdier things like the suspension.

You may have missed the two bolts on the bottom rear of the airbox; they are hidden by the bracket in your photo. See this diagram, page 35, bolt #12 (looks exactly like the bolts in front):
http://www.porsche.com/all/media/pdf...85_KATALOG.pdf
But again you may find it unnecessary to remove the airbox once you have the timing belt cover unbolted.

Be aware that if you remove the accessory belts you will find that one of the two nuts on each of the tensioning struts is reverse-threaded.