Porsche Enthusiasts Club Forum

Ok I know its difficult to diagnose engine noises over the P.C but im hoping someone can help. was out for the day today & driving back home there was a really bad vibration coming the from the engine that resounded through the entire car, both when driving & if I dropped the clutch & revved it, after a while it went away, but noticed a rhythmic noise not consistent with either engine revs or speed, again this went away for a while but came back again shortly before I arrived home.
I left the car running & popped the bonnet & there quite a bad rattling noise coming from the front of the engine. Now I've had some work done by Porsche lately which involved Cam belt change, balance belt change, power steering belt change, alternator belt change, a new water pump & bottom front crank seal, all this plus new rollers ,tensioners, bolts etc. could the fault be related to this work, either a faulty part or something worked loose ? any help appreciated, cheers, Tony

ok my guess first.....

loose cranshaft bolt, simple test grab the pas pulley at the engine base (not the one on the pas pump) and see if there is any movement. This would also usually shop a drop in oil pressure.

2nd guess is either loose pas pump or alternator.

Thats the easy ones to check. I wouldnt run the engine any more till you can diagnose.

Thanks for that, ok, well oil pressure is superb on this car, even with this problem, so I don't think it's that, secondly, the pas is on the left, alt is on the right, but the noise is coming from the middle of these & much higher up, from around the cam belt cover or just behind it, gonna have a word with porsche in the morning & see what they say, will let you know, cheers , Jinxy

cool, could be so many things.

Mights be a waterpump impeller coming off its shaft or tensioner failing.

Were either done?

Finally if its near the cam tower hard to say without removing some components.

Don't drive it pack to the PC get it towed.

balance belt?

http://www.porsche968uk.co.uk/phpbb/viewtopic.php?f=7&t=10670

Yep water pump was replaced along with every belt & every tensioner by porsche main dealer, it's definitely coming from inside the timing belt cover as I used a Lind screwdriver as a stethoscope and you can hear the knocking coming from there , I'm have having it collected tomorrow and transported back to them do they can take a look, this better not cost me anything, I already weighed out £1800 to have that lot done by them so I hoping for component failure on what they've replaced. !!

how much OMG!!!!

Yep exactly that's why I'm not impressed. ! They did a thorough check of the car too even advising me that my headlight washers were not adjusted correctly FFS !! So they better not have missed something far more serious !

Ok, just an update on things, the car was collected this morning & we went to Porsche, they took the car in, removed the cam belt cover, we waited for around an hour & he came back with a very sorry looking Balance belt !!, very frayed, teeth missing in about four different places, he'd never seen a new balance belt do that before, hes checked all the rollers, tensioners etc & all are running smoothly, the belt is a genuine part & hes put it down to faulty manufacturing, so now its in their hands, the guy who's been working on the car has worked on all the 944's as hes been with them for around 25 years & assured me he will do a thorough check & test on it all before it leaves them, im just glad im not putting my hands in my pocket again !!!

for the price Porsche charge for belts I bet its been on the shelf for the last 10 years
current price £125.00

Gates or Conti less than half that

Ridiculous price for a belt, but I bet your right !!

That's an 'easy' fix though.... could have been much worse.

Glad they're sorting it for you

glad you got it sorted.

that sounds like total BS to me even a belt sitting 30 years (which it wouldn't have been) wouldn't shred like that. I reckon the balance belt rode back to the engine due to incorrect routing, tension, tensioner the wrong way round or a loose bolt....etc!

Lucky escape!

I personally wouldnt waste your time and find a decent specialist, they will be more familiar with your car and see more of them! Wonder when the mechanic did his last 944 belt job, 6 years ago......!

well to say I feel better about things tonight than I did last night is an understatement, I really couldn't afford a big bill at the moment if it was something else that had gone wrong, don't get me wrong, the car is immaculate, anyone who's seen it will tell you that, but I have so much to shell out for in the next 2 months ! it would have had to wait & I hate not driving the car, even if im on hols I get withdrawal symptoms LOL !!

I would not put 30 year old tyres on my cars even if they had been stored in the dark

Belts are made of very similar stuff

Would you ?