924Board.org

mass_havock · Joined: 15 Feb 2004 Posts: 8 Location: McIntire,IA

I just bought a 924 a little while ago and I was wondering about the oil pressure. When the car is cold the guage reads 6 when idling. After the car warms up the guage will drp to about 2. Then after about 20 min. of driving the guage will read 0 and the lite will come on. Even if reved up the guage rarly gets over 2. I know the book says that if drove for a while the lite will come on but also the book says it should be at about 7 if the car is moving. Is this normal or can this be a problem?
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1977 Martini Rossi 924

Lizard · Posted: Wed Feb 25, 2004 8:41 am Post subject:

the oil pressure will peg out on start and then when warm sit around 1-2 bar, the oil pressure light comes on at .5 bar, which some bounce off of, they the bar should raise about 1 bar per 1000 rpm, ie 3000rpm 3 bar, and it will max at about 4-5 bar under normal driving conditions w/ synthetic oil, if your pressure is low it indicates 2 things #1 worn bearing, #2 weak pressure relief spring in the oil pump, either case you are better off imo pulling the engine and just rebuilding it.
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3 928s,

CMXXXI · Joined: 05 Nov 2002 Posts: 1939 Location: Vicksburg, MS

Sounds low, and yes it could be a problem if those are accurate numbers. I'm guessing you've checked to ensure your oil level is topped off? You should be running 5-7 Bar at operating temp and 4-5000 RPM. Could be bad wiring/contacts for the sending unit and/or gauge, or a bad sending unit. Possibly, but less likely that your pump or pickup is gummed up or clogged.
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'79 Eurospec 931

Smoothie · Posted: Wed Feb 25, 2004 9:39 am Post subject:

Mine dropped to about 1bar and the light came on one time while waiting in line for inspection. It freaked me out a bit, but just after inspection, I pulled over to check the oil and found that when I turned the headlights off, the pressure reading popped up about 1 bar. So when it happens, check it both with and without lights and other electrical components - the low reading could be part electrical.
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"..it's made in Germany. You know the Germans always make good stuff."

'82 924T, US version, dark green metallic, 5 speed Audi 016G gearbox

Neil924 · Joined: 18 Mar 2003 Posts: 4225 Location: Canada

Damn, guy with the dog picture is right. My car does the same thing. The lights go up and the oil pressur dips down. huummmm, I'm no mechanic but I didn't think the iol had anything to do with the head lights, guess I was wrong!

gohim · Joined: 02 Nov 2002 Posts: 4459 Location: Rialto, CA

When the plastic elbow on the camshaft oil supply line gets old, it shrinks and leaks out the oil pressure.

MGQ · Joined: 19 Dec 2003 Posts: 53 Location: southwest MI

does your gauge read Bar or kp/cm^2?

mine is kp/cm^2, it starts out around 9 or so, and fluctuates between 3 and 7 in city/highway driving.

I've never had the oil light come on, but it sounds to me like your pressure is a bit lower than normal.
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Brown 78 924. 4 speed, AC, Sunroof

kike924 · Posted: Thu Feb 26, 2004 8:07 am Post subject: Mine Too

I guess most 924 have this issue because mine also drops to 1 bar when the lights are on.
I posted this question in the french 924 forum and they told me that because of electric ground problems many 924 mark a lower oil pressure reading when lights are on

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Euro 924 1980 N/A
Daily driver + week end racer

Finbarr · Joined: 14 Jan 2004 Posts: 85 Location: Worcestershire, UK

I would guess this is mainly related to the standard weedy earth straps connecting the engine to the bodywork and battery. When the lights are on, a lot more current is drawn from the alternator, causing a voltage drop across the earth strap, rasing the voltage at the ground connection of the oil pressure sender and reducing the current it draws through the oil pressure meter. An additional effect is probably to reduce the supply voltage to the meter, also causing a drop in the reading.

Beefing up the earth connections and adding a new cable from the alternator to the battery on my 931 has improved problems like this considerably.
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1980 931 (with the odd electrical quirk...)

augidog · Joined: 03 Mar 2003 Posts: 1360 Location: New Jersey

Change your oil to semi-synth castrol.
I have not seen the red winking oil light since.
The cam oil tube elbow helps a lot too.

low idle maybe ?
I run my idle at 1000 rpm.
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1978 924 95 mile daily driver.
Audi TB/POR174M/High Flow Cat/2.25" exhaust
I knew that positive thinking thing wouldn't work.

mass_havock · Joined: 15 Feb 2004 Posts: 8 Location: McIntire,IA

thanks for your help then. i have taken the valve cover off and checked to see if there are any metal filing but it was all clean. Ill have to check that elbow then. got the car stored at a friends garage 3hrs. away from me so ill have to run through the motor then.
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1977 Martini Rossi 924