Euromagination

hi all,

when my car isn't started for 2-3 days (rare, but it happens), there;'s a very loud and raw 'buzzsaw' sound coming from the engine right upon start-up. it almost sounds like something is moving, hitting, or running without oil for a second or two; but then after the first couple moments, the sound goes away. the car runs fine and there are no performance problems.

if i drive my 964 every day as i normally do, this sound NEVER occurs. it has NEVER happened when the car has been warm or driven 'recently'. like i said, this only happens if i let it sit for more than a day without driving it... i guess that's another reason i think it's oil related since obviously oil drains to different places after a day or two of sitting...

i think i may have posted something about this before a little while ago, but i ran a search and couldn't find the old thread. someone last time mentioned that it could possibly be a cam chain dragging? could it be possible that this sound is related to a slight oil leak out of my cam chain housing? i don't even really know where to start right now but i want to track this problem down myself. i just need to kick around some ideas here first...

i just don't want this problem to turn into anything worse and/or bring any extra wear to my engine and associated parts. that would completely suck...

thnx again,
harry

Heirsh

Yeah I have the same problem when my car sits for a while. I'm pretty sure my problem is the chain tensioners. Someone investigated and determined (or was told) that a likely culprit is an o-ring (seal?) that is decrepit and is allowing the oil to escape from the tensioner when it sits.

It is a horrible sound isn't it? I was hoping to get ahold of an old tensioner to see if I could just replace the seal. I never did though.

Euromagination

Yeh... I've looked at all my books and I can't seem to find any diagrams of this part of the assembled engine. ???

Does anyone have any diagrams or possibly know how I would go upon fixing this? I just need some direction and I can probably figure the rest out, I'm sure...

...and yes, it's a horrible sound for sure. The first time I heard it, I thought my engine was literally about to blow up or break into a million pieces.

JasonAndreas

Try HERE and HERE.

boze_man

harry and heirsh...this buzzsaw sound you are referring to could it be like the jangling sound from "jangling at cold start" post???? seems we are all dealing with a cold start noise...mine noise sounds like piston slap in a 2 stroke motor (i.e. chainsaw/buzzsaw) or could maybe described as a "chattering"...am i making any sense or am i describing it wrong???

i had a wrench mention what it could be and he said the same thing as yours ...cam chains and lack of oil on startup??

the one article jason linked to has bob w replacing the spring tensioners and rails and noise vanished...thanks again jason

Heirsh

The best way to describe the sound that I've seen is does it sound like a chain being dragged across the lip of an open metal barrel?

My answer is a resounding yes! But its only a sec when the car has sat for a while.

Until each of us fixes our problem, and I am in no hurry to mess with mine (maybe next year), we wont know if we share the same one. I don't know myself, but if you were really hearing piston slap wouldn't it last a lot longer? it takes only a sec to get oil in a tensioner, but to heat up the pistons and such would take a minute or so, right?

boze_man

regarding the piston slap sound, i was just trying to describe the sound and what it reminded me of, pretty sure it is not slap...it sounds like we are hearing the same thing, but are describing it differently...

Euromagination

Yeh it's always really hard to put a sound into words. I'm going to try to make an mp3 recording of the sound next time I think it will happen...

JasonAndreas thnx for finding those old threads. I honestly don't know how you did it. Usually I'm not too bad with the search function...

So we're thinking spring tensioners and rails huh?

JasonAndreas

If you pinpoint the noise as coming from the camchain boxes before you replace anything try cleaning the tensioners, it has worked for a few people.

boze_man

we just have to get our stethescopes per jason...

jason is that part of the TV repairman kit?

Larry Herman

It sounds exactly like a loose chain tensioner. Piston slap is a knocking noise that sounds just like a diesel truck idling. I know, I have one of those 2002 GMC 6 liters. 89,000 miles of piston slap and still running fine.

boze_man

thanks larry...at least someone knows what sound i am describing...

f11 posted what his "jangle" sounds like in his thread...i have to think we are all dealing with the same problem...

https://rennlist.com/forums/964-forum/271491-cold-start-jangling-noise.html

take a look see...later

JasonAndreas

Unfortunately not even my dad's ultimate set of tools has a stethoscope, I inherited (I think) mine from my grandmother (she worked on radios... )

CraigC

Harbor freight sells a nice automotive stethoscope for about $6. I have one and it works great.
Link: http://da.harborfreight.com/cpisearc...cope&Submit=Go

boze_man

anyone listen to the wav clip in the other thread?? similar sound??

also i do notice that my noise does not seem to go away completely...i only hear it when i am in gear and shifting at low speed...when the motor is under load...if i take it out of gear and rev it i dont hear it....but i do hear it at idle on start up...very odd...