Different Oil Pressure Question

[MarcBC]

I have the car booked into my local OPC next week, but what could this be (and don't scare me too much!)?

I went to drive the car last week and on start up, it said "check oil". I had never seen this before and it was odd as I had done so only fairly recently and it was 3/4 full. This time it was down to plus 1 bar over minimum. I put in just under 500ml and it went back up to 3/4 full.

Anyhow, since then the pressure guage has taken on a mind of its own. Sometimes it sticks permanently at 5, irrespective of revs, other times it works normally and other times it drops to 1.25 at rest.

It was fully serviced in May, with the extended warranty taken out (perhaps now will be a test of its value)


Any ideas?

 

[adrian996]

Hi Marc. I'm not sure how au-fait you are with the oil system on these cars so forgive me if you already know this.

The chances are that you probably measured the oil level when the car wasn't completely level on the ground (parked on slight slope, etc.) and that the oil level was slightly low as well. Also, I'm assuming that you measured the oil level whilst the car was cold. All fluids (including oil) expand when they get warm/hot. The oil in your engine will take quite a while even at tick over to come 'up to temperature'. The on-board computer oil measurement should only be used when the oil is up to temperature. I would also suggest that there's a chance that your OPC may not have filled the oil up to the top either as they wanted to avoid overfilling it.

So, how do you know that your oil has reached temp? I'm pretty sure that your C2S has an oil temp gauge? Failing that look at the oil pressure gauge which will drop to around 2 bar at tick over when the oil is warm. The gauge will stick at 5 (top) when the oil is still cold and then settle to around 2 bar when she's warmer.

Having said all of the above, if your oil pressure gauge is jumping around all over the place when the car is warm and engine is at idle then your oil pressure sender is probably faulty. Mine broke down at 11,000 miles and I'm guessing that it'll be the same sender unit in the 997 engine as it is in the the 996. The sender cost me £25 I think and half and hours labour but in hindsight I wish I fitted it myself as it's an easy job.

Whatever the case, I would say that these readings are not a true reflection of your actual oil pressure or circulating volume.

Hope this helps.

 

[MarcBC]

Thanks Adrian,

'twas the sender unit, replaced under the extended warranty. Along with a new set of horns (one had gone and the car sounded a little feeble with just one working!), also covered under the warranty.

I was given no paperwork though, is this correct?

 

[adrian996]

Hi Marc. I think that you can request the paperwork and they'll give it to you - they might have an environmental policy on printing stuff out - or rather NOT printing stuff out. Regardless, it will have gone on the Porsche UK database against you car details I would have thought.

Just a quick point about your (new) horns: the same thing happened to my 996 because I was getting a bit over zealous with the hose when I washed the car. If you squirt the water in an upwards direction under the front spoiler the water can fill up one of the horns (there are two) which faces the ground. The water goes up in to the horn and can't drain out unless you remove it and do it yourself. If it gets full enough it will render the horn useless and you'll be in the same position again - so be ware!![]

 

[MarcBC]

Good point. I always ask the local Albanians to do an undercar wash when they clean the car; they use their pressure washers. Perhaps I will ask them not to from now on.