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Oil Pressure question

xenon

xenon

New member
On the S2 I looked at yesterday (and place a deposit on) I seemed to run beautifully with no nasty noises or anything, but I have a question related to the oil pressure gauge. As I understand it, starting a cold engine the pressure should read about 5 bar, dropping to between 2 - 3 bar when hot, and maybe even between 1 - 2 bar if very hot, but never below 1 bar. (is that correct??)

This car went up to 5 bar OK on cold start, but after having driven for about ten miles (temp gauge just below half-way) the pressure was reading about 4 bar. Does this sound like the pressure regulator? Or simply the wrong oil grade?

Should I be worried? [:'(]
 
When Driving my gauge shows hovering above the 4 mark and three when static, I questioned it some time ago and was told that's about normal, it's never been below three. What year is it and when'd you pick it up?
 
Should be getting it on Thursday, 1991 S2.

First jobs are engine / gearbox / diffential oil changes, plus re-build the cam chain tensioner. Belts just done at OPC but can't find any mention if the chain has ever been looked at. Doesn't sound 'lashy' (I drove some that sounded awful) but I'll change the nylon ramps to be on the safe side.
 
You're correct - all these pressures are at idle.

Was that 4 bar at idle when hot? - you should see 4+ bar at 3-4k rpm

Also bear in mind oil pressure at idle is quite dependent on idle speed - can be a fair bit higher at 1000 rpm than at 800.
 
Mine rarely drops below 4bar at idle with full synthetic 15/50W, with lesser oils it drops lower. I would rather have hi oil pressure than low,
Tony
 
Arrgghh. The "buyer" of my car, despite leaving a £100 deposit, has just phoned to say that he can't get the money together. [:mad:]

I am so p****d off - I'd put a deposit down on the 944 to pick it up on Thursday. Now it's all fallen through.
 
well I hope you don't return his deposit. It should be non returnable or else it was a worthless gesture . Sorry to hear things have fallen through. Have ya tried your bank for a short term personal loan which you can pay back when you sell yours ? ? the Alliance & Leicester are one of the cheapest atm.at about 6% with no penalty for early redemption.

I would be a little concerned at the temperature of the S2 . I have only known blown head gaskets or non working fans cause that higher temperature. It should be barely on the first bar even when hot in traffic jams . If its any higher then its definitly cause for concern.


 
The temperature wasn't high - below half way, just over the first bar. I don't know if that's normal temperature, from what you say I guess it is.

I certainly won't return the deposit to my buyer - I have someone else viewing the car tomorrow so it might turn out alright.
 
An eternal plague of locusts in the butthole to all timewasters [:mad:][:mad:][:mad:] (including my customer who cancelled her appointment with me as she opened the front door today [8|])

The oil pressure readings on that S2 sound perfectly normal and should not put you off the purchase. Good look with finding a new buyer for yours
 
Buyer has called me back - he's been able to get the money together after all, and will come on Thursday as planned. [:)]

I'm back on to pick up my 944 on thursday evening. [;)]

Thanks to all for the advice, by the way.
 
I know I'm a bit late here, but I think that the Porsche 944 S2 handbook says that the pressure should never drop below 0.5 bar at idle ... Mine has never gone below about 1.5 bar (on a VERY hot day, in a VERY large traffic jam, after quite a long time.)


Oli.
 
Thanks Oli - this one didn't seem to go below 4. I agree that high pressure is generally better than low (especially with hydraulic lifters and a hydraulic chain tensioner) but I just wondered what owners found to be normal.

One S2 I tested the oil pressure went up and down like the rev counter - 1 bar at idle and 4 bar at 2000 rpm and over. This one seemed to be fairly static at about 4. I wondered which sounded safest?
 
Xenon,

Alot depends upon how hot 'hot' really is. For instance, when I drive 20 miles to work on an average UK day, the oil pressure won't be much below 3.5-4 at idle when I arrive. This is gentle open-road driving in a 50 limit most of the way (so travelling at 50-60 in 5th) with lots of fresh air flowing over the cooling matrices at the front of the car.

If I take the car by the scruff of the neck and fling it hard down a country road on a very hot day I can, and do, expect the pressure to be a lot lower when I arrive.

Sitting in a traffic jam on a very hot day seems to be the worst. I have a personal theory that if the car in front has the exhaust pipe at the right height and you are in the right position behind it, their exhaust gasses will flow right over your oil cooler, thus heating the oil slightly, dropping the pressure quite dramatically.

Interestingly, there is only ever slight variation on the temperature gauge - which is water temperature, I believe. This is usually around the lowest line, but gets up to about 1/2 way or slightly more in situations as described above.


Oli.

(Should add that in the recent weather conditions, I think I have a newly-installed water-water cooler and oil-water cooler in the front of the car, in place of the more normal radiator and oil-air cooler, but then so has everyone I guess!)
 
Oil pressure gauges should be used as a rough guide only; I have just changed the oil pressure sender in my 968 as it was very erratic often dropping to zero pressure (makes for a worrying moment, but it was obviously electrical not mechanical so not a major worry). However the new gauge reads differently by about .5 bar at all times, which one was right? My S2 is different again, but both read well within the bounds of normality and I am happy with both cars and their readings. Just take the readings lightly and monitor the car over a period of time.
 
So it's the final countdown, get some pictures on here asap (just don't ask me how to), is it a decent drive home from collection?
 
A decent drive? About 1/2 a mile! It's amazing after scouring the country to find one so close. I'll post some photos on friday if my iffy camera plays ball, otherwise they'll be camera phone type things. I shall be changing the engine and 'box oil on Friday, along with plugs and filters, and I'm also going to fit a bi-xenon HID kit (if it arrives) - I'll post some installation photos of that which others may find useful. Looking forward to it now! [:)]
 
So no traffic problems then, I'd only done a post last week on the poor level of lighting, and bought myself some new bulbs, be interesting to read about installing that kind of improvement. Good luck,
 
Thanks. The last three cars I've had have all had factory-fit xenon / bi-xenon (hence the nickname!) and I swore I'd never have a car without as it makes such a difference night driving, especially out in the sticks where I live. Of course, nobody had heard of HID lighting for cars when the 944 rolled off the production line so a retro-fit is in order. I'll try and do some before and after pictures.
 
Maybe teaching you to suck eggs, but check you can undo the fill plug on the gearbox before the drain - they're often a git to get out on a 944.
 
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