Oil Light Flashes below 1500 rpm

[IanHighfield]

Hi all,

This is my first post, and is bought about by the oil light coming on below 1500rpm !

Only started yesterday after about an hour run at moderate speed.

Oil tank is in fact over full, gauge shows full, and light goes out above 1500rpm. I get 3+ bar pressure at 2000rpm so everything looks as normal (except the light coming on).

I have owned the car (my first Porsche) for 7 very enjoyable months without a problem. Had it inspected by PCT and will be taking it there for an annual service, new silencer, new front oil pipes and cam oil lines (I think!) later this year.

If anyone can throw some light on what to look at, I sure would appreciate it.

Thank you,

 

[Guest]

Are you reading the oil level using the dipstick, with the engine running, on a level surface and with the oil up to temperature?

 

[IanHighfield]

Brian,

Yes, I checked the level as you describe. Did it at the time the light came on. Then drove some 10 miles home and pressure was just fine, and the light was out.

Light only comes on when idling or briefly between gear changes if the revs drop.

Have not started it again from cold as I hope it is not a bad sign.

I am on a limited maintenance budget !

Thanks,

 

[Guest]

Highfield,
What oil are you using: what is the weight? (10-40W?) Age?
Oil filter- how old (miles?)
I would also check the oil pressure with a seperate dial gauge, connected via the oil port where the oil sender screws in. This way you can ensure the wiring/gauge are telling the truth.
replace the oil with a 15-50W oil- doesn't matter what type.
If all this agrees with what you have already seen, then the problem could be else where.
I'd check pressure relief valves, thermostat's.
What type of oil filter are you using? There is a whole heap of stuff on the net re bad oil filters... typically "fram" are one of the worst![:-] I'd be surprised if this is the problem as filter is on the outlet from the scavange pump ( 2 pumps in c/case). Main pressure is from second pump through to various outlets (bearings, cam, etc).
Check it out.
Peter[]

 

[Guest]

I think SC's and later had two senders, one for the oil pressure warning light and one for the guage. If so then maybe the one for the light is failing/intermittant.

Cheers

Andy

 

[IanHighfield]

Thanks Peter and Andy.

Unsure what oil is in there now, as car was serviced November 2002 - about 2,500 miles ago - oil 'looks' clean on dipstick. Is due for a service in next couple of months, and will discuss oil with PCT (local independent in Coventry).

I do not have a 'spare' dial gauge to check the reading with, but would do so if I had one !

Can you recommend a good manual (Haynes, POrsche etc.) as I have not got my fingers dirty with maintenance for too many years now, and had hoped to get through this year before needing to start - looks like I will have to start early.

Thanks for your input and help.

 

[Guest]

Go for the Bentley Manual - do a good search first as you may get a good deal (mine cost £75 but was worth every penny)

Roy

 

[Guest]

Check-out Pelican and Rennlist tech forums, lots of ideas and tips.
http://forums.pelicanparts.com/forumdisplay.php?s=&forumid=8
http://www.rennlist.com/
[]

 

[IanHighfield]

Have spoken to PCT and they will check / replace the oil light sensor at the next service. This is apparently a know 'weak area' and often gives problems.

So long as the level is correct in the tank, and the pressure gauge is working as normal, then I shall not worry too much !

I will also get hold of a Bentley Manual - does anyone have a good 'used' one ?

 

[IanHighfield]

Driving home this evening in the dark for the first time this year !

What should I notice, but that the parking brake and brake pad warning light come on and off at the SAME time as the oil warning light - hadn't noticed in the sunshine !

They come on below 1500rpm and then off they go as the revs rise.

Putting the handbrake on, and then revving the engine when stationery - oil light and brake pad warning light go out, but the handbrake light stays on as usual.

Very strange - I am NO electrician so have no idea what to think.

Car runs great, does not overheat in any way, and haaaas good oil pressure.

Any clues as to what on earth (no electrical pun intended) could be wrong ?

 

[Guest]

I 'THINK' this is a feature of the cars. Some models have the oil pressure warning light and the handbrake light connected in someway. I'm no electrician either but have seen this mentioned a number of times on the Pelican forum. I believe you can also see it in the Haynes and Bentley wiring diagrams.

As long as you continue to have good pressure and right amount of oil 'I' wouldnt worry to much. If you are concerned then get it checked sooner than later.

Cheers

Andy

 

[steh]

I have a friend who had the same problem on his 3.2, both lights came on at the same time. i used his car and cheacked all that you have. In the end i think he got a new oil pressure light switch and this cured it.

steve

 

[Guest]

The oil pressure light switch is most likely to be the problem if the gauge is reading a healthy pressure. However, don't put off replacement. The switch starts off weaping oil and may eventually fail suddenly causing a fountain of oil under pressure in the engine bay. I had exactly the flashing light syndrome. It will get worse, and eventually not go out at all.

I changed the switch on my car in about half an hour. It is located on the top of the crankcase at the front of the engine. You need to take the air filter assembly off, and you will need a deep socket to remove and replace the switch, and it is a bit of a bugger to get at. Don't believe people who say you have to drop the engine - you definately don't on a 3.2. When I changed my switch, the outer casing was very oily, suggesting impending failure.

Alistair

 

[IanHighfield]

Thanks to everyone who replied.

I will be ordering the switch pronto.

All I need know is a good used Bentley Manual - anyone know where I can get one.

 

[Guest]

Dear Ian,

I had the same problem as you.

Do not get mess up, go directly to the oil sender switch. This is behind the intake manifold, very close to the air intake box.

You wil have to remove the air box and AMF box. This switch cost around 10 pounds, if you are a basic mecanic, very easy to change. You will need a 24 mm long neck socket.

regards,

Antonio
(87) 3.2 Carrera (SPAIN)