John D.

OK - let's try another tact..?? Now - don't shoot the messenger - OK - BUT - clutch throw out bearing??

MarkD

I was thinking possibly crank thrust bearing...
Worst case scenario, hopefully NOT it.

But this is a 95... so it is less likely since clutch does not need to be depressed during start up.

Is it only on cold starts? Or every start?

BobbyT

Yes, it is a 95, and it does this with the clutch engaged, so I doubt it is the TO bearing.

It is more of a shrill sound, so I doubt the crankshaft thrust bearing also, coupled with the fact that it never makes this noise except on startup.

More prevalent on cold starts. I haven't noticed it on hot starts.

MarkD

hmmm...
well, crankshaft thrust bearing, symptom is "squeal" on cold starts.
How long has it been doing this?

I really hope this is not it.

EDIT: Bobby, here is a thread more on this topic. https://rennlist.com/forums/showthre...ferrerid=35947
Did I mention I hope it is something else? It really should be something else since the issue is mostly caused by a stiffer pressure plate.
Given what you have already ruled out, I am having a hard time thinking of what else it could be without hearing it in person... trans perhaps pilot bearing? Doubt you would get that sort of noice out of it though.

BobbyT

Hi Mark and John D,

I just took the car down to my favorite shop (Precision Motion in Riverside, CA), and although they couldn't pinpoint the cause, they are confident it is not the crankshaft thrust bearing. They had the transmission out a couple of months ago to correct a loose pinch bolt on the 5/6 shift fork, and replaced the RMS "while they were in there", even though it was and still is bone dry. They think that if the thrust bearing was failing, I'd be having oil leaks and clutch problems. I hope they are right.

They think the noise is more in the area just above the distributor, where all the heater stuff is. I can't think of anything in that location that could be making this noise. I plan to pull the distributor next, check it out, make sure it spins free with no excess end play, and inspect the caps/rotors. At that time I will pull out the heater stuff and start the engine with it out to see if that helps.

Input from rennlisters is sincerely appreciated--keep it coming.

John D.

Hey BobbyT..!!!

WAIT - don't pull the distributors yet, OK????

With the engine off - disconnect the blower fan (left top of engine - you will see the harness connector to the left of it).. Then - try to start it....

Just a hunch - but - I could be wrong...

Best to you!!

JD

kdurg

Interesting suggestion John....why this recommendation ????

I take my heater blower assembly out for the summer and just reinstalled it for the winter. Car upon cold start ups has (intermittently) now began to make the same screeching nosie the OP describes......

Thought it might be belts as there is a 2 second delay before she starts when the screeching exists, however, belts/tension are fine as is the pulley.

BobbyT

Hi Keith,

It sounds like we have the same sound (not trying to be punny). Mine is exactly at the point where the engine fires off, and lasts about a second at most, kind of a tinny screeching, louder when the engine is cold, sometimes almost inaudible when the engine is good and hot.

I'm thinking about tin parts in the heater system that might make a noise like this, but none of this system is active during startup, is it?

This should be a happy time for me--just got wifey a new MBZ E350 last night, but I'm obsessed with this danged noise.

grwoolf

Could it possibly be the starter staying engaged with the flywheel for a second after the engine starts? I've had a car w/ a sticky starter where the starter gear would not immediately disengage when the key is released. The engine would start, and freewheel the starter gear for a brief second before it would disengage. It was kind of a metal, screeching sound, but it's hard to say without hearing what you are talking about. It would be hard to mistake it for slipping belts, much more metallic, more like a failing bearing.

BobbyT

grwoolf,

I had thought it might be somehow related to the starter, because of the timing, but the sound seems somewhat distant from the that location, and perhaps too screechy/tinny to be make by something as stout as the starter/flywheel interface.

roger's 2937

I had a similar sound at start up of my 996 and I traced it to a loose sparkplug, tightened it and no more screeching at startup.

Roger B.

Crimson Nape Racing

I have the exact same noise, but it never bothered me cause I assumed it was the belt sensor roller thing. Now if you guys say that's not it, it will probably bother me. Interesting comment regarding the spark plug - not sure how that could make the noise I'm hearing, but if it's not the belt.....?

BobbyT

John D and Keith,
You guys win the Golden Wrench Award (along with Steve Weiner via email). It was the heater blower--I disconnected it and the noise disappeared. A special thanks to you guys, and everyone who responded.

cgfen

me too
reading this thread with interest.

craig

Crimson Nape Racing

well, FWIW, mine was the belt sensor. I sprayed the stuff I got for the windshield squeak on it last night and no squeak on start-up this morning....