Hi,
I have a 1994 V8, just bought recently.
Going ok till after a service i had, i'm not saying the service is the issue but i noticed it the next day.
i'm noticing when i start the engine there is a loud grumbling sound from the engine bay that almost vibrates the car.
Not every time i start the car , but almost.
Not a metal on metal sound,.
If i was to try to explain the sound i would say it sounds like if you drove over a finely corrugated surface, car vibrating an a quick regular vibrate.

I've tried to pin point it but not successful yet, by the time i start the engine and start feeling around the engine its gone, it's also more loud inside the car than with my head in the engine bay.

It last about 30 seconds, i thought it was happening the same time as the brake accumulator on start up, but that may be a co-incidence as it does not happen every time the accumulator goes while driving,
It also happens on occasion when i'm driving, sometime after 30 minutes driving, but only happens once.

I know this is a vague description but any advice or tests to pin point it would be appreciated

 

Maybe the harmonic balancer. I do know some of them come apart over time. Maybe the belt tensioner... Can you post a video of it and upload it on here?

We could pinpoint it almost immediately with that.

What service did you have done? Exactly?

 

I'm not quite sure why would you put it as grumbling sound, but that's normal to a V8...

 

We either need to start placing, or moving these engine/driveline/under the hood related threads to the proper forum.

Your noise issue seems to be something like the power steering pump pressurizing and venting air. You can check for aeration in the fluid after you've started the car to see if it looks like that is the case.

 

This was the case I had in my v8 SC daily beater the other day .. bubbles inside the reservoir, low fluid, then when I filled it up, startup noise disappeared. (It was not a whining sound caused by no PS fluid.. more of grumbling/bubbling sound)

 

i'll take a video of it on my phone and upload it tomorrow, what is the harmonic balancer?
Had an oil change, filter, replaced bush's, gear box was sagging.

 

would this only occur on startup, or would i constantly hear the grumbling sound?
just checked reservoir, full and no bubbles

 

My bubbling/grumbling sound was only on startup .. that was before I filled up the reservoir. After fillup , no more kinda aeration sound .

Harmonic Balance is the dampener ( big pulley on that crankshaft). If you still have the original one, the rubber part might be cracking is what I believe , Mark was trying to say.

 

ok, i've narrowed it down to the air suspension pump, must have a leak somewhere

here is a sound clip


http://www.youtube.com/watch?v=o8RE0...ature=youtu.be

 

I was just now looking in the engine bay to see if anything was amiss

I noticed a tube just hanging down, so getting under the car i see another tube which may look like they are meant to connect?
There is a white hard tube that looks like it is coming from the radiator bottom near the battery, 4 inch's back, away from the front of the car is a bendable grey tube just hanging there, are they meant to be connected?
is this related to the air suspension?
i can get some photo's if not clear

 

One of them is the rad drain, but what is this other tube hanging down?