oil pressure

I have a problem, maybe. After replacing the oil sender, my oil guage shows 3-4 bar at idle (1000 rpm) while cold. As the temperature of the oil warms, the pressure comes down to 1 bar at idle, and rises appropriately with higher RPM. Is this something to worry about. I am using a higher weight oil now 20W-50 (valvoline).

thanks matt 78 911SC

That's the way mine reads. Specifically now that its gotten cooler. As the oil warms the pressure drops to the more normal range.



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Gunter
'82 SC Targa

On our 1987 the pressure is about 1.5 bar at idle and goes up as RPM. I am using Redline 20-50 so the pressure is a little more constant. Bruce Anderson has said that the oil warning light may even flicker at idle when warm and that is okay on older higher milage cars as long as the pressure goes up as RPM.

Your oil pressure readings sound exactly like everyone elses I heard of so far, including mine. I have never had the green light flicker after I relpaced my sender though.
Nothing envolks fear into the heart of a 911 owner like the thought of all of a sudden having a steadly green light acompanied by a flat line needle at 85 mph on a stretch of interstate.
Which raises a good question.
If that were to happen...what would be the best course of action???
Throw it in neutral until you can brake below like 30mph then shut off the ignition?
When you turn off the key the wheel might lock if you aren't careful and you'd definately have to mash the brakes to completely stop.
Hope I never have to find out.


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Leland Pate

___79 SC Targa

Matt

This is exactly how your oil preassure is supposed to be like. The oil preassure gauge should read about 1 bar for each 1000 rpms. So 1 bar at tickover (when warm) and 4 bar at 4000 rpms. When cold at tickover it's meant to read 3-4 bar. My 84 3.2 does it too.

No need to be nervous.

Leland,
I too hope that it will never be necessary to cut the ignition while driving because of lacking oil preassure. A friend of mine sold his 1976 2.7 Targa to someone who definetely didn't know much about cars. 3 weeks ago my friend phoned me to say that the guy who bought the Targa had now trashed the engine. He had never checked the oil level and on a motorway the engine suddenly started to sound strange. The guy ran it without oil!!! So now the car just sits in the poor guy's garage with no engine.

So everybody; don't forget to check the oil level!!!

After you've put the key in your car and turned it, the steering colum unlocks, and stays unlocked until you REMOVE the key. Next time you remove the key, listen and you'll hear the click. Not just Porsches.

If an engine looses all oil pressure while you're driving, the damage is probably already done. At 3000 rpm, the engine is turning fifty times per second. So, if this happens, TURN THE KEY OFF IMMEDIATELY, coast to a stop (your steering will not lock unless you pull the key out) and pray. Not joking.

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'83 SC

Jim, there's still a good chance things stayed lubricated long enough for you to shut down the engine. When a car starts there's a good twenty seconds in which not all the moving surfaces aren't yet lubricated with fresh oil. Admittedly, it's not a good thing to have happen, but it's not automatically a disaster.

What would cause a catastrophic loss in oil pressure, anyway? The oil pump is connected directly to the crank. If the engine's running, the pump is pumping. Educate me on this.

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Mark Szabo
1986 911 Targa 3.2

Mark,
One way is if all of the oil is dumped out, as in a major oil line failure etc. Happened to a work collegue in his 3.2 Carrera. Hit at big rock in Malibu Cyn, tore off one of the major lines @ 70mph. Engine was toast.
Chris C.

Actually, the oil pump has the intermediate shaft between it and the crank! And, the intermediate shafts have been known to fail, so given the propensity for the oil pressure gauge to peg at max when the sender element fails ... I would recommend killing the engine the instant you see the oil pressure gauge drop to zero!

That 22 mm scavenge line that loops under the bellhousing is a farly stout piece of steel tubing, but a large, sharp rock could hole it in a second at highway or track speeds!

[This message has been edited by Early_S_Man (edited 10-24-2000).]