s65e90

IMO this isn't the car for you if you're concerned about mechanical noises. These motors sound terrible but it's the nature of the motor itself. Drive a Honda if you want a quiet engine.

WOTever

You're wrong, I have waited a VERY long time to buy my dream car and I love every second of my ownership. This is exactly my car. It took me quite a while to find a yellow/black manual X50 of non-dodgy provenience and she's a keeper.

I am an engineer and when I see/hear something unusual I want to know why. Not all cars make that noise, I have driven 996tt with more miles and zero noise.
Also that noise develops over time is indicating some sort of wear.
I checked the engine with a stethoscope and the noise is coming from the area above the drain plug, where the oil pump drive and the snorkel is located. I have read all kinds of explanations like chain noise (quiet in my engine) or backlash of IMS gears (quiet in my engine too).
I am wondering if the hollow oil pump drive shaft which is floating between oil pump and IMS is making the noise or maybe the oil pump internally?

I'm not losing sleep over this but it would be nice to find a cure, no?

jungt

WOTever, I agree.

Does your noise only develop after the engine warms up?

John

WOTever

Yes, quiet with cold engine. I ran the engine from cold and listened with the stethoscope and the noise above the drain plug slowly appears and gets louder as the engine warms.

s65e90

Likely because cold oil versus hot oil.

s65e90

What's being an engineer have to do with it? Like it or not, I'm not wrong. this is not a conventional engine by any means. #1 it's sideways. It uses chains that slack, and IMS that rattles. Every 996 I have been in sounds like rocks in a can. Why worry? Does it run? Drive? If it's not broken then what are you going to do? You're looking for peace of mind, no? Why try to find a cure for a problem that doesn't exist?

cdk4219

He is spot on, not wrong. If your car doesn't make this noise you are definitely lucky. Most of these cars make that racket, obviously not an extreme cause for alarm, but if you want an engine that makes no noise, you need to look elsewhere. He'll even the Kubota diesel in my tractor is less clanky than some of these cars. Consider yourself blessed by Ferdinand himself if your mezger sounds unmetallic.

s65e90

I run semi-solid engine and trans mounts with a stock flywheel. Sometimes I come to a stop and it sounds okay, sometimes it sounds as if someone is sitting in the backseat with an empty can full of rocks, lol.

IMO if it runs well, forget it and move on. These cars weren't made to be "quiet". If my engine suddenly became smooth and quiet, I would then be concerned, lol.

"02996ttx50

^ completely agree, they ALL sound like varying degrees of rattle cans. some moreso than others.

if they did NOT i'd also be concerned. that said, coming from any car.. takes a bit to get used to this cars "normal".

Gt3stig

read above again guys. His noise is coming from above the drain plug.

Third-Reef

It does matter if you are an engineer,because you want to understand why something is happening not just what it is. If you don't understand the difference you probably are not an engineer. My bet is on IMS shaft gear back lash and i think i know why.

cdk4219

Well trying to understand why German engineers do certain things may take some time, and more money than that time. I also love when my 40,000 mile 997 turbo goes from cold cranking immediately to 3500 rpm, all while making those sounds. I will tell you that the 2003 carrera convertible that my wife drives m makes none of those noises, doesn't puff any smoke on start up, is very smooth running, doesn't use or leak oil. When it starts up I don't cringe, but it is an LS1 from a 1999 firebird. From strictly an engineering standpoint that's how I fixed it.
You could always tear the engine apart and see if you can repair the problem, but again time and money will dictate your success.

WOTever

Amazing that people accept the status quo without desire to understand the why.
The engines left the factory without rattle, now most (see youtube) rattle. They all sound like mine. Some don't rattle at all. Interesting, no?

People have various explanations from "Hans Mezger designed it, therefore it is ok if it rattles" to chains to IMS. That's not specific enough for me. I'm just curious if anyone else has taken the time to really identify the source of the noise.

s65e90

I accept it because I have been around cars for the past 20 years and have been taking them apart and re-building them for 20 years. I have owned 30+ cars and each one is different. Again, if it works then maybe nothing is wrong.

This reminds me of the M3 forum days, where guys would obsess over the mundane.

You know the old adage, "if it ain't broke ....."

s65e90

So true. Engineers design cars without any thinking as to the future, i.e. the serviceability of the car. Take a look at the oil temp sensor location. Behind the oil filter housing, butted up right against it, and angled towards the front of the car. It's not terrible to change, but you'll look at it for a few minutes and say, WTF. Plenty of parts on these cars that are maintenance related were designed with no common sense for the future mechanics who will/do have to service them. Any work on a P car revolves around taking tons of other parts off just to service a simple part. (Water pump??? Lol)