Oil pressue, temperature and level

[Guest]

I wonder whether anyone can shed some light on a problem which has reared its head on my 1981 911SC Coupe. Whilst travelling at about 95 mph on the motorway last week for about 10 minutes, the oil temperature needle moved from its usual place at the top end of the curved rectangle to about one third of the way up to the red sector (it has never moved before). At the same time, the oil pressure dropped to about 2 on the gauge (normally sits at about 3.5 at this speed), and the oil level needle dropped to just above the red (it normally sits at the top of the gauge and is very steady).

Needless to say, I slowed right down, and exited the motorway. I had to stop at the top of the exit road, and the oil pressure read almost zero at tickover. I drove the car around the exit roundabout (still with some oil pressure when above tickover), and low and behold the oil level needle went back to its normal place. I drove back down on to the motorway, and the oil temperature gauge returned to its normal place on the curved rectangle after a few minutes. The oil pressure improved, and the oil level gauge remained at the top of the gauge.

I reached my destination, but the same thing happened during my return journey, and again the oil level gauge returned quickly to its normal position and the temperature settled back down after I had negotiated a corner or two.

I checked the oil level with the dipstick (engine up to temperature and running of course!) and all was well.

It's as though the movement of cornering had some effect, but possibly this was just coincidental.

Any ideas would be gratefully received before I take it to the garage.

Thanks

Colin Judd

 

[steh]

hi colin, wired, in the past few weeks there has been a few posts re the oil pres.
don't know how long you have had your car but the oil level guage should not normally sit at the top when you are moving ( or any thing above idle speed), bu should flicker up and down .
as to the other problems you done the right thin by pulling up and cheacking the oil with the dip stick. did you make sure that the fan belt is not slipping, normally get a high pitched squreel sound as well..


sorry i cant't be of any more help.
i see that this is your first post, you do get a lot of good replies so keep cheacking.

good luck and keep us posted.

steve

 

[bones]

Welcome Colin, hope you'll post here often now. Steve's right when he says the oil level indicator should pretty much register in the red bottom zone of the gauge when on the move and then gradually move up the dial at a standstill. In my car you can almost imagine the oil running back into the tank as the gauge rises. Agauge that sits at the top all the time indicates an open circuit. Check the condition of the contacts on the oil tank level sender visible inside the right rear wheel arch. You may need to remove mud and road grime to find it. Try cleaning and or replacing every fuse and and fuse holder and every visible sender or sensor contact on the engine and see if the situation improves. To satisfy yourself about the oil pressure - very important - your Independant should be able to perform a pressure check while you wait and confirm good pressure , ring around for some prices and get to work cleaning contacts, you can't do anything but good in an old car but make sure you use the right fuse values.

 

[Guest]

Steve

Thanks for your post. Been on hoilday, hence my delayed reply.

I'll have the oil level gauge looked at - it was replaced about 4 years ago, and has always tended to read right at the top of the gauge ever since. The fan belt is OK and certainly not making any noise.

I'll keep you posted as to what my garage determines.

Thanks again.

Best wishes

Colin

 

[Guest]

Bones

Many thanks for your reply.

As I have mentioned to Steve, I will get the oil level gauge looked at.

Your comments on the fuses are welcome - I understand the fuse holders on SC's are prone to playing up as the years move on.

I'll have my garage check the oil pressure - the engine was rebuilt about 20,000 miles ago and has been sweet ever since. This has been the first time that I've had any change in the oil pressure/temperature readings.

I'll let you know the outcome.

Thanks again.

Best wishes

Colin

 

[oilyrag]

On my 2.4S oil pressure is quoted as 5 barg at 5000 RPM at 80 deg.c and I would have thought it would be the same on SC's ..........if so yours would appear to be a little low for a rebuilt engine .......if the guage is accurate.
Anyone know if this is also correct for an SC ? [8|]

 

[bones]

The rough rule of thumb is 1bar /1000rpm, anything above 4,000rpm and mine reads the highest level but has never done anything different in twenty years of ownership.