Hi, I recently became the owner of a 1974 914 1.8. The car has been checked over by a UK Porsche specialist and been found to be mechanically sound but there is an intermittent strange whirring/rubbing noise that comes from the rear.

I say intermittent as the noise only appears after 20 mins or so of driving and stops when driving under 25mph and returns again when driven over 30mph.

The noise doesn't get any worse with speed, in fact it appears to get better but that maybe due to being drowned out.

The mechanic could find nothing wrong.

Does anybody have an idea of what could be wrong or how to identify the problem?

Many thanks.

Possible rear bearing. Do a search, this has been written up before. Had they been replaced by the PO ?

I have the exact same issue with my 914-6. It's a very strange sound, one that you wouldn't expect from a wheel bearing but I don't know what else it could be. I purchased a new set of rear wheel bearings but haven't had the chance to install them yet. If I get mine changed before you do I will post the results here. If you get yours changed before I do, please let us know if it corrected the problem.

Well just a guess BUT on some road surfaces my tires will make a funny sound ...Just a thought ..got a friend with some extra wheels and tires change them over ...give it a try good luck please post what you find

While driving down the road (With noise present) rock the car back and forth a little. Just enough to swap the weight from one side to another. If the noise quiets down on one side and gets heavier on another or vise-versa, then it's most likely rear bearings.

They can be bad, quiet and out of round causing the forever rear shakes.

They can be smooth, but noisy.

They can be smooth, quiet, but have play and be bad.

50% of all 914's I've ever worked on have needed rear bearings.

Funny thing is that My 914-6 does the same thing,When I bought the the car PO told me about,well on the way home it started.Its like a Eek,EEK eek sound then all of a sudden it stopped.The interesting thing that it has never did it again.Rear wheel bearing ??
914

Is it a high pitch sound? I have a similar problem on mine and wondering what it is as well. High pitch sound, only happens after driving longer distances, not from just around town, it seems. High pitch sound, from the rear, not able to tell which side of car, and hard to detect at all except if driving alongside a wall or some other structure that reflects the sound back. No vibration or anything.

It's definately a high pitch sound. Kind of like your kids squeeky wagon wheel. It starts making the noise after about 5 miles of driving and you have to be going faster than about 20mph. Just past 20mph it starts and pretty much sounds the same at 70mph. Take it out of gear at 70mph and coast all the way down to 15 or 20mph before it stops. I've done all the swerving back and forth, coasting out of gear, shutting the engine off at 50mph and coasting and it doesn't change the sound. It is definately not coming from the tires or anything related to the brakes. It's got to be the rear wheel bearing.

You've probably lost a seal and grease. Sorry, I didn't realize it was a high pitch sound. My 2 cents would be on the rear bearings still.

well, first:

and second: i have the same over 30mph intermittent noise that seems to come from the rear. it goes away under 30 (you said 25). just let me say that i have driven on the noise for 4 years without incident so you may have time to investigate and make sure you PM me what you find out so i can fix mine!

That's the sound of the treadmill the hamster uses....

I have the same 'squeak' and too have purchased wheel bearings, but have yet to install them... Drives me nuts! The car has to be warm and going over 30mph.

same thing here...it comes and goes with no detectable pattern. Goes away when I swerve to the left.

I hope it isn't the bearings because I've heard that isn't a fun job at all...

Exactly!

I AGREE wheel bearing. they can be obvious or just a "ambient noise" that seems to drone at ifferent speeds.

i used to have a whine coming from the passenger seat, got a divorce and it went away...

That's the noise Eek, Eek. Consensus is its probably the bearings. I doubt if the previous owner changed them. I'll let you guys know if it cures the problem.

Thanks for all the suggestions.

Exactly the same problem as I'm experiencing.

OK, so assuming it is the rear wheel bearings, how tough of a job is that? Is there a "DIY How to" somewhere? I did a search on the list of articles but did not turn up anything there.

Thank you

Yup, you can do it yourself. It's no easy task to do correctly though. CV axels have to be pulled which means new gaskets and re-packing those while your at it.

Lots of write ups on 914/911 Rear bearing replacement. Good tip: Stick those new bearings in the freezer the night before the job.