CCCP

On my 86 na the oil pressure always fluctuates at idle. When cold it is pretty steady at 4-5 bar, however when fully warmed up it'll fluctuate violently between 1-2 bar. I am now running 20w-50 oil, before when I was running 10w-40 the fluctuation was even more violent. With throttle application the fluctuating goes away. Engine pulls good, sounds good, and I found no metal during my last oil change. What is the problem?

zoltan944

if its early model that is normal, if its newer its still fine, but the sender may be dying.

cjeckert

Often times just a quick little cleaning of the contacts will stablize it.

CCCP

I've been told that a fluctuating oil pressure is the result of my rod bearings going bad. Anyone second that idea?

Calmchaos

Mine did that.
Until my sender died. Now it reads 0 all the time. Problem solved I suppose
-Brett

CCCP

bump

Rip It

mine does it occassionally, idle cold 4/5 bar

CCCP

Bump

eohrnberger

I'm also runnig a heavier weight oil, 15w50 Mobile 1. When cold, the oil pressure at idle will sit at 5 bar or slightly below. I figure this is pretty good.

When all warmed up, like after 20 minutes driving, it'll sometime go as low as just a hair over 2 bar at idle. Always steady, not moving up and down. It struck me as 2 bar is a little low. Do I need to be concerned?

Sysgen

Mine started doing something very similar this afternoon. It was running fine and I went shopping, was in the store 20 minutes, came out and the car started fine but the idle was uneven,

Here is a link to a video of what it does Video

A tap on the trottle and it goes away. I have not confirmed if it does it cold.

Any ideas?

'90 S2

mkd944

Low oil pressure can be an indication that rod bearings may be going bad. I recently had a low oil pressure reading on the dash gauge of my 968 and was prepared to change rod bearings but the problem turned out to be a bad sender. Sender was replaced and readings are good again.

Mike Dayton

callmethewanderer

my '87 does the same thing, the needle bouces at idle it seems the wise thing to do is the simple things first, clean contacts... change sender... then if it persists look for more serious problem.

Sysgen

It doesn't explain why a small tap on the trottle fixes the problem. This means that the sender is ok.

I checked Clarks-Garage on this and the only thing he has is a writeup on ajusting the idle but, as I learned, the S and S2 do not need adjustments because they have "adaptive idle speed volumetric efficiency regulation"

Wow that's a mouthfull

Sysgen

Bump and it's confirmed, it does not do it when cold.

Fishey

Sysgen you have a bad ICV or a bad referance sensor... Also check the alternator output!