Noise from oil tank

[mowog63]

Hi,

Recently, I've been hearing an intermittent noise from around my oil tank on my 85 Coupe.

It has only just started making this noise in the last month and it is getting more persistent - it sounds like chattering coming from the passenger rear wheel well where the oil tank is.

When it began to make the noise it was only when the car was cold...once it warmed up it went away.
Now it is not going away when the engine is up to temp....but it does stop when I let off on the accelerator.
But then it comes back again when on the throttle.

My temp gauge never goes past 8-8:30, pressure reads between 3-4 at idle and pulls to 4.5 on the throttle, dipstick and gauge both read midway at temp.

Any ideas as to what is broken or breaking?

Thanks,
Erik.

[Uncle Enzo]

Are you sure it is in the tank and not possibly a chain tensioner going out?

[DRACO A5OG]

PO may have dropped the original dip stick in it. Stick a magent stick retriever and see if anything sticks to it and pull it out.

+1 it could be a residual sound from the chain tensioner. Post a video next time it happens, we could possibly tell. Liken to a chain inside a metal garbage can. Which brand and weight of oil are you using?

[mowog63]

I only replaced the oil that I drained when I had to replace my oil return tubes and that was with Pennzoil 20W50....four quarts.

The oil is clean and looks as clean as when I put it in.

But I've read other threads that mention the "chains inside a metal garbage can" sound, but it isn't like that.
It almost sounds like a squirrel cage fan going bad.

[mowog63]

Now you have me thinking Draco....

I just read another thread and you mentioned that a rattle noise might be the alternator.

I only got the sound intermittently before....but I just changed out the loose fan belt with a new Porsche fan belt and it is nice and tight now (1/4" deflection at center span).

Could it be the alternator bearings?

How long can I run the engine safely without the fan belt on?

[Uncle Enzo]

You can run it long enough sans belt to eliminate that as being the issue.

[tharbert]

Mine might be a different animal being a 72 but... Occasionally, I would get significant gurgle from the oil filter on cold starts. Once everything was warm and primed, no sound.

[Discseven]

Erik... could be oil plumbing retainer is loose or dropped off. Then plumbing vibrates/rattles/chatters against car.

[sp_cs]

Something that made a 'buzzing' noise was posted on the IMpactbumpers forum - it doesn't sound quite like your noise but worth a check:




I've read previously that non-genuine oil filters can cause gurgling noises based on different bypass valve designs.

[mowog63]

Chattering is a better description of the noise...I ran the car tonight and it was much less prevalent and/or common than yesterday.
The noise is not there at idle. And it doesn't increase/decrease with the engine speed.

But it isn't consistent at all....

[DRACO A5OG]

Okay, +1 remove fan belt and run for a very brief moment to remove that from the alt from the list.

Sound travels, it could be the AAV ( ambient air valve ) at cold start, if it is metal, you have the OEM and te plastic one is the superceded part but it also needed new bracket if you want to stay Concours.

It is also on the oil sump side.

[moneymanager]

Did you install a strange new oil filter just before the noise appeared? They have been known to cause very odd sounds.

[mowog63]

JH,
No new oil filter....


Draco,

I was going to take a picture of it, but I think you've nailed it...I read your dialog about this in another thread after seeing your post here about the ambient air valve.

My air valve is a Pierburg and it looks newer and black plastic.

It makes more noise the colder it is outside.

I'm feeling more confident that through this dialog we may have isolated the culprit....now to fix it!!!

Thanks,
erik.

[DRACO A5OG]

keep us posted Brother Erik

[WYDBODY1986]

Erik, can you hear the noise from inside the car? Does it sound like it is coming from the rear on the passenger side just below the rear window? If so I am trying to track down the same kind of noise that sounds like a metal on metal rattle like a heat shield is loose is the best way I can describe it. When I check in the engine compartment the it is hard to isolate between the exhaust and all the other noises the engine makes but it does sound like it emanates from the same location your are looking at. Does anybody have a picture of the AAV?

[mowog63]

Wydbody,
Yes and yes.

[WYDBODY1986]

Thanks Eric, I know that piece, I'll start there I guess too!

[GH85Carrera]

When mine went bad it sounded much like a kazoo. Totally strange sound from a car. The replacements have a new hose that you will need as well.

[ppetion]

Resurecting an old thread , was any of these issues resolved ? I am facing ing the same here .