Whining noise when hot

[unknownmale]

This has been getting progressively louder over the past year and I still haven't gotten to the bottom of it.

1.8ex (1987)

Here are the symptoms:

- Sounds like a bad alternator bearing
- Only audible when engine is at temp
- Changes pitch with engine revs
- Does it under load & in neutral
- Loudest at 1500 - 2000rpm

I have ruled out:

- Alternator (I replaced it last summer with no change to the noise)
- Water pump (As above)
- Cam belt (Did think it was the tensioner for a while, but this was also changed a few months back)

So the only thing I can think of is the cam shaft?...But never heard one sound like this before. I've tried a placing a long screwdriver at different areas on the block and not really pin pointed it to anything.

If it is the Cam shaft, the engine has covered 146k so perhaps A heaver weight oil might cure it, especially with summer?

Hopefully I'm missing something obvious and easy!

[james butler]

gearbox?

whining sounds usually bearing noise, have you tried putting your foot on the clutch, if the noise goes away/changes its most likely the thrust bearing in the end of the gearbox.
but if it doesn't go away with your foot on the clutch it could be the main shaft bearings on their way out inside the gearbox.
there aren't any serviceable bearings in the camshaft so its unlikely to be trouble in that area.

[unknownmale]

Sorry, should have mentioned It's an auto. I did an atf flush and replaced the filter last summer, Don't think it could be as it's still present in N and P so it's not under load, the only think moving would be the front pump and torque convertor. Will try and record the noise this weekend

[Little_bro]

torque convertors can get a bit noisey. I've had two 944's auto both with noisey torque converts.

[mark1gls]

The cam belt may be a little to tight, as the engine gets hot and things expand the cambelt gets tighter.
Check the cam belt tension and may be losen it a little bit as it must be near being right as if it's to tight they whine all the time.

[unknownmale]

The cam belt may be a little to tight, as the engine gets hot and things expand the cambelt gets tighter.
Check the cam belt tension and may be losen it a little bit as it must be near being right as if it's to tight they whine all the time.

I did suspect this at one point, but after changing the cam belt and tensioner a couple of months ago with no change I ruled it out. Fairly sure I set it right and there was no change at all with the noise from before to after...Should get a chance to record the sound tomorrow! But does sound identical to a bad bearing

[unknownmale]

Uploaded a vid to record the noise - https://www.youtube.com/watch?v=dMOoJzYwsEg

[Nate]

Checked Cambelt cover isn't catching the belt? Sounds like the noise mine makes now and then

[unknownmale]

Checked Cambelt cover isn't catching the belt? Sounds like the noise mine makes now and then

When I did the cam belt a few months ago it was making the noise before I put it back on....That would have been nice fix

[Neillyboy]

I'm with Nate on this one. The bottom inner part of the cover that is on before you put the belt on can cause this. I've seen it a few times.

[scrumpyone]

As above. I also had the same problem a few years ago.

[scirocco-monkey]

Is it safe to leave the cam belt cover off? I have a strange noise similar to yours but not as loud and I was thinking cam belt cover too. I havent tried it yet but will in the next few days.

[unknownmale]

Is it safe to leave the cam belt cover off? I have a strange noise similar to yours but not as loud and I was thinking cam belt cover too. I havent tried it yet but will in the next few days.

It's fine to run it without the cover to test, but not a long term solution.

This weekend i'm going to take the covers off and run it to temp, if it stops making the noise then i'll search for any obvious markings on the inside of the cover and bend it out before refitting.