keick

I'm new to the porsche world, just purchased an 89 944. It runs great, and I've already done a few things such as rebuilding the power-steering pump, and new rotors all around.

However, there seems to be a tapping sound coming from the engine. It's not loud, but it's there. Almost as if the rockers had excess play or something. Is a faint tapping sound normal, or should I start looking in to a few things? Suggestions?

Also, there seems to be a fair amount of hum from the transaxle. Is that normal as well. I'm a truck guy, and it sounds a little bit like a truck diff sounds when the backlash is to tight. Thoughts? Maybe just an fluid change with some "really good stuff"?

sca037

First of all......welcome!

Use a mechanic's stethoscope (or piece of pipe) to determine where the 'tapping' is coming from. It might just be from the normal operation of the fuel injectors.....they're louder than on any other car I've had

The transaxle 'hum' might be more problematic, so as a first step I suggest replacing the gear oil with fresh fluid (I've used Mobil1 75W90 for many years with good results).

Cheers,
Brian

keick

Hey thanks, I'll swap the fluids tommorrow.

Also, I was driving tonight, and at about 5 grand in third the car got significantly louder, and felt a vibration in the back, and felt it through the shifter.

Is there any type of "cleaner" I should add to the transaxle? I know most of the junk out there is snake oil, anything worth trying?

Toolmaster

Keick -

Welcome again! I think you'll find the 944 series all Porsche - and a blast to own and work on.

The injectors on these cars are LOUD - so that is a good potential. The mechanics stethoscope is a good idea - though does the sound change (get less loud perhaps?) when you rev the car a little? Lifters in these cars tap when they don't fully pump up with oil.

As for the tranny - an oil change is in order to start with. Is the humming perhaps at around 2300-2800 RPM though? If the balance shafts on the engine are out of time - they will tend to make the car hum a bit at those RPM ranges. When was the last time a clutch was done on the car - do you know? Don't add ANYTHING other then the specified gear oil to the transaxle - and make sure you yank out the fill plug BEFORE the drain plug. Sometimes they tend to stick - and a drained tranny that you can't fill back up is a bummer to own.

You'll also find Rennlist an invaluble resource - welcome again to the club!

keick

sca037, Toolmaster,

Thanks for the tips. I don't think I can adequately describe the humming sound. It's faint enough to not really bother me yet. The noise and vibration at 5 grand does bug me a bit, but I'm hardly ever up there.

As far as the clutch goes, according to the records from the previous owner, he had a clutch put in novemeber of 1997. According at my car-fax, that puts it right at 20,000 miles ago. Should I be worried about the clutch already? It engages very smooth, and I have never felt it slip.

bleucamaro

Welcome.

My S2 also has a rearend/transaxle hum that I can barely hear.

As for the clutch, get under the car, and on the drivers side of the bell housing, theres an opening and you can see the slave cyl piston. measure from the left side of the opening to the end of the piston, and IIRC you need to replace if the gap is more than 36mm (someone please confirm) If the clutch is bad after 20000miles, I'd start to be worried about a whole load of other things. It should be fine.

keick

Changing the tranny all but stopped the noises at 5 grand, thanks a ton. Oh, and the tip about the fill plug was a smart idea. Those things were a royal pain. Sears didn't carry a socketed 17mm hex for the plugs, so I bought a standard hex wrench, cut a peice off and slid it down a 17mm impact socket. Made very quick work of it.

I will crawl under and check the clutch this week.

Thanks again.