aerolithe

I got a 1991 S4 with 157000KM. Just bought the car in April. The owner just change the oil before delivering the car(5W50). Did 1400KM to get home and start having the warning light for low oil pressure. Under suggestion from some supplier from this site a change the oil for 15W50. Everything as been find since until yesterday the light and warning for low oil pressure come back. Any suggestion?
Leaking injector and washing a cylinder wall?

FredR

I always run a 20w50 but then I live in a hot climate as well. For the oil you are using the hot temperature viscosity characteristic should theoretically be ok but I personally believe that is not the full story. /what you did not mention was what pressure was showing on the gauge. This should read 2 barg at operating temperature. If you see this reading and the alarm goes off it may just be a false alarm but if the gauge suggests 1 barg and the alarm goes off then chances are the reading is correct and therefore worrisome..

You can change the oil to 20w50 to see if that resolves your problem but suggest you feedback what oil pressure is indicated on the dash. Oil pressure senders commonly fail at this age point and if it has not been refreshed, chances are the wiring that carries these signals is also shot. Take a look at the 14 pin connector on the passenger side of the engine bay next to the hot post and take a look at the condition of the cables entering the top half of the plug coming from the engine., If you can take a picture and post it.

Mrmerlin

if swapping the oil doesnt do it then.

If you observe these following indications,
a lower than normal idle oil pressure after the engine has run for about 5 mins,
and then at hot idle after 15 miles, the light is coming on and the gauge is at or below the 1 bar.

I would suggest to pull the right side cam cover and see if one of the oil pins has fallen out.
I am not sure when the change was made to have the updated metal pins installed.

Ref this thread.
https://rennlist.com/forums/928-foru...oil+block+pins

aerolithe

Thanks Guy's

All good information I will report finding later.

aerolithe

Just remove the right valve cover and the 2 black cap are at there place.
The light light up when the engine is warm at idle. cold I got more than 5 bars. Warm at idle I got little bit over 2. In neutral no light put in gear the light come on.
The electrical connection under the jump post was having some bare metal. Put some tape to isolate them. Some tight place to work. Some big line just need to be replace they break when remove from the vacuum actuator.

aerolithe

1. Good day,

Problem seam to be fix. The electrical connection at the 14 pins under the post was not looking to good. Next step will be a new harness.

Thank again

FredR

When we give advice/recommendations we always appreciate seeing some pics showing what you found- a list protocol as it were.

SeanR

What you are experiencing is getting more and more common due to the deterioration of these harnesses. I've shipped out 5 in the last 7 days, let me know if you would like me to get one out to you today.

hupp

I may be interested in a harness for my '79 5-speed. I have been repairing more and more problem areas. Can you provide more information?

Taguid

Hey hupp. Nice to see I am not the only 928 around here.

hupp

Nice! I haven't seen any 928's around here in years.

hupp

Here is a more updated pic of the '79.

SwayBar

Great looking color!

Ninespub

^^^^^^^ What he said!

skpyle

hupp, 2 things:

1: That is BEAUTIFUL!!!

2: You REALLY want one of Sean's harnesses. Money very well spent.