oil light

[kev13]

got abit of a problem with my 2.8 my oil light coming on only so much of the silly buzzer sound i can take

the light will come on when i have done about 10 miles with out fail even if the car has been running for about 15 mins on the morning its -8 to +1 here on the morning.
i can even just jump in it on the morning and it will still can on more or less at the same point

i have seen this is a common problem when looking even with the 2.8 passat but no one says how there sorted it only some people put high pressure oil in seen something about the cluster can be the problem ?

i have did the following
oil level is on the max
changed the oil pressure sensor
cleaned oil pump out was full of bits and sump
pump been checked all ok
fitted new pump got it cheap off a mate thinking old one may have been temperamental
new oil and filter 5w-30 fully syn
put some engine flush oil through it

[ainarssems]

You need to check oil pressure with mechanical gauge to see if is low or if it's just reporting low pressure. Do 2.8's have oil level sensor as well or just pressure sensor?

cleaned oil pump out was full of bits

This does not sound good




Edit:

Had a quick look, 1998 2.8 30V ACK engine does not have oil level sensor, just pressure switch and oil temperature sender but oil temperature is not used in A8 so it's only pressure that is reported to dash. And i'ts a simple pressure switch. If pressure above 1.4 BAR it's closed circuit, if pressure below 1.4BAR - it's open circuit.

So if you have oil light on there are several possibilities:
1. Low oil pressure
2. Faulty pressure switch
3. Wiring fault between switch and instrument panel
4. Faulty instrument panel

[sloss]

As he said above - you must get an actual gauge on it.

I would add that fully synthetic can be a bit OTT for an old engine - I don't know the miles or use etc.

The Oil Light switch is only to alert for low pressure not level/volume.

As you took a load of rubbish out the old pump it looks like some damage has occurred to bearings so clearances are bigger so pressure is reduced and so on.

Brace yourself for bad news

[kev13]

Originally Posted by ainarssems

You need to check oil pressure with mechanical gauge to see if is low or if it's just reporting low pressure. Do 2.8's have oil level sensor as well or just pressure sensor?


This does not sound good




Edit:

Had a quick look, 1998 2.8 30V ACK engine does not have oil level sensor, just pressure switch and oil temperature sender but oil temperature is not used in A8 so it's only pressure that is reported to dash. And i'ts a simple pressure switch. If pressure above 1.4 BAR it's closed circuit, if pressure below 1.4BAR - it's open circuit.

So if you have oil light on there are several possibilities:
1. Low oil pressure
2. Faulty pressure switch
3. Wiring fault between switch and instrument panel
4. Faulty instrument panel

im starting to think #3 or 4

pressure is good can not remember what the pressure was left paper at mates garage

sludge is normal is the 2.8 engines from what i have found engine has 110k on it

[ainarssems]

cleaned oil pump out was full of bits

sludge is normal is the 2.8 engines

Sludge and bits are different things but there should not be much sludge either if decent oil has been used and changed regularly

[kev13]

have found loads of posts when looking on the net about sludge been a problem
and it has a full service history by audi