99three

I noticed that my oil pressure guage was in between the 1-2 bar at idle (closer to 1 as it was getting hotter in traffic) with the temp between 9-10 o'clock. Seem kind of low? 40K with brand new M1 5-50 oil. With a hot motor where does your oil pressure sit at idle?

Pan58

sounds about right

99three

Your oil pressure sits between 1-2 at idle with the oil temp between 9-10?

Doc V.

At idle, oil pressure should "remain between 2.0 and 2.5 bar" at 70-90 deg. C., according to the 993 service manual. Sounds like your car's engine's oil temperature in traffic is running close to 120 deg. C.--close to too hot.

shamrock

Once my oil temp starts heading towards the 9 pos'n , my pressure at idle heads towards just above 1 bar .. 50k miles on the clock.
is your low speed fan kicking in just above 9 o clock?

jimbo3

Seems pretty warm. Is the temp needle near the third mark (the one at the 10 o'clock position, 248 degrees)? Most stay slightly, but noticably, above the second mark (~8 o'clock, 194 degrees). At that point, mine reads about 2 to 2.5 bar with Brad Penn 20-50 at idle. It used to read between 2.5 and 3 bar with M1 15-50. My oil temp guage will sometimes go to 9 o'clock.

As already stated, check your oil cooler fan.

AM993

No worries Serf, it's normal, mine does the same when I am stuck in traffic: oil temperature slightly above 9 o'clock and oil pressure at between 1 and 2 bar. I use the same oil as you. Until last year, I was running M1 15w50, the pressure would never drop below 2-3 bar. I guess that thinner oil means lower pressure.

Stealth 993

Oil pressure is adversely proportional to temp. As oil temp goes up, the viscosity goes down, so you get slightly lower pressure.

IMHO, I have found that M1 seams to have lower pressure then most other top synths.

Ed Burdell

Yes, mine sits just below 2 bar at idle, but last week with the hotter temps it was more like 1.5 bar.

I use M1 15W50, and my oil cooler fan is always on high speed (by design, not accident). Temp hovers around the first mark. 78K on the clock.

99three

Thanks for all the responses guys. I t turns out that I am using M1 15-50. There's a definite relationship between heat and viscosity, one goes up while the other goes down. I think my gauge is slightly off. It has never pegged at 5 even at start up, just slightly under 5. I figure the rest of readings will be skewed as well.

99three

BTW, owner’s manual states that at times, ‘the oil light may light up momentarily without harming the engine’. Food for thought.

Redblurr

Rennlist is awsome! My questions are answered before I even ask them. You guys are always one step ahead of me. Ive been wondering about the same thing for a while now.

99three

Update and good news (I think?) I did a diagnostic on the oil cooler fan. With the assistance of PCar Workshop on RL.
I checked the relays and jumped terminals 3(30) and 7(87c) for slow speed : Does not work! I then jumped terminals 3(30) and 5(87) for fast speed : Works fine! Same with the AC condensor fan speeds.
Next. With the car started I turned the AC on and the condenser fan started. Good news.
Next. I removed what I think is the oil temperature sensor cable (from the passenger side headlight) to invoke the high speed fan. Now it's always on.
Does the oil cooler fan resistor need to be replaced?

99three

I'm wondering if a high speed fan switch should be installed instead of replacing the oil coller fan resistor. Any pros/cons for doing this?

Edward

You can replace the resistor for peace of mind. But were it me, I'd simply replace the resistor If/when I were already in there ...too much trouble otherwise (for me, anyway). The better solution (IMHO) is to simply add a discrete high-speed fan switch. It's easy, and I deploy mine before the temp needle even gets to 9:00 ...9 and above is just too hot for my comfort.

No cons to leaving the bad resistor in except that you "may" forget to check your gauges and therefore must rely on manually kicking the fan in to cool the oil. So it's up to you. But anyone driving any 911 should make it a habit of check gauges regularly ...especially an oil-cooled car.

Edward