Re: Low Oil Pressure Indicator Light on 86 4kcs Q

[James Marriott <marriott@micron.net>]

Chad Frederick wrote:
> 
> Heres My Question for the list,
> 
>         Ok this is the story, I changed my oil about 2 weeks ago on my 86 4kcs Q.
> I used 10-40 castrol dino juice and a non-OEM oil filter, but by no means a
> low quality oil filter (I waiting for the OEM filters to get here from
> Blauf).  Everything is fine for about a week when the low oil pressure
> light comes on and buzzes while I am driving above 2000 rpms for about 4
> seconds.  I think nothing of it since, I thought it could be the oil filter
> not having the correct oil flow parameters for an Audi.  The indicator
> light did not reappear until exaclty one week later.
> 
>         Now today while on a scenic cascade drive the buzzer repeatedly came on
> several times for 10 or more seconds each time and would then quit.  It
> only came on sparacticly and would not continue for very long.  I checked
> the oil and it was not low at all as it was the first time the the light
> came on.  I then began to notice at higher rpms (above 2000) a light
> clacking sound coming from the motor and after that as well as when it
> idled.  Because of the clacking I ruled out a defective sender unit.  The
> Engine is not overheating.  I do not think it is the oil filter being
> clogged since it is just a couple of weeks old.

Clacking does _not necessarily_ mean bad things; many of these "old"
cars do same. Lifters are a common--and unrepaired--cause.

>         So, I believe it to be one or more of several things:
> -Oil pick-up strainer defective (can you just pull the pan and clean this?)
> -Oil pressure relief valve defective.  (I do not know what this is)
> -Oil pump is worn or the mountings are loose. (would the light stay
> permantly on if this was the problem?) Is this the symptoms of a bad oil pump?
> -Worn main or big-end bearings.  (I do not know what this it)

Probably (fingers crossed) a crappy sender or a toasted
oil-pressure-warning-buzzer brain (makes noise below certain PSI/bar and
above 2X00 RPM).

Determine which sender makes the buzzer "live." Near oil filter (I
think), under #3/4 plug, and back of head are locations. Then remove a
convenient sender that's _not_ the buzzer one, and screw BY HAND a 1/8"
NPT 0-100 PSI or 0-6 bar mechanical gauge in there. Then get the car to
make the noise and verify on the gauge that the pressure is not low. I
haven't had a problem on the 4kq (no OP gauge), but the buzzer's been
killed on the 4ks (0-5 bar gauge) for years. Used to be the same problem
. . .

> I will not drive the car until it is fixed so no
> further damage can occur.

Good thinking, and good luck.

James
'87 4kq
'89 200q