Oil Pressure

[Lyn]

My 3.6 engine (20,000 miles) gets between 1.0 and 1.5 Bar oil pressure at idle which equates to about 20 PSI. At speed (3,000 rpm) it reads 4.5 to 5.0 Bar which is in the 60-70 PSI range. I'm OK with the high rpm pressure, but am wondering about the idle number. What are considered to be normal parameters for oil pressure for a 3.6? Thx for your input.

Lyn

[logray]

Totally normal.

What ambient temps does the car normally operate in? What weight oil do you use?

[Lyn]

I'm in Phoenix, so the ambient here ranges from low 40s to 120F. My referenced pressure readings are at an ambient of 90-100F. I'm currently using Mobil 1 0-40w, but will be switching to Motul 5-40w.

Thx for your response. I'm a recent 997.1 convert after 6 years in a Boxster S without an oil pressure gauge and wasn't sure what was normal.

[logray]

In Phoenix during the summer 5-40 or 5-50 would be the minimum choice for me.

I might consider running 15-50 during the summer and 5-50 during the winter.

Or just 5-40 or 5-50 all year round, since technically there is not a 15-50 approved oil from Porsche for 997.

[Mijostyn]

Hi Logray,

I have appreciated many of your learned reponses in other threads.

The single most significant change in the SN and Porsche oil spec calls for much lower amounts of ZDDP. Zinc dialkyldithiophosphate is one of the industry's major friction reducing agents. Unfortunately, the phosphate can f-up modern catalytic converters. Problem is older, pre 1985 cars are losing their valve trains on these newer lower ZDDP oils! If your car does not burn oil it is perfectly reasonable and probably better to run oils with the older SM spec additive. Even if your car did burn oil, a few hot laps will burn the phosphate right off. I use Millers Oil CFS 5W 40 NT. They also make 10W 50 and 10W 60 weights. These are all fully synthetic, triple ester SM spec racing oils with a nano particle additive. If I were tracking the car I would go with the 10W 50. Much of the current oil dogma is based on CAFE standards and polution control not on what is best for performance and durability. The only fly in the ointment is that these oils were designed for racing not long oil change intervals. Harry King at Performance Racing Oils tells me that his partner ran his Jag for 20,000 miles on a single CFS oil change with a great TBN and no measurable loss of viscosity. All the same I plan on having my oil analyzed at 5000 miles. Frankly, if there is any performance benefit in a street car it is purely psychological. It sure makes me feel great knowing there are trillions of nano ball bearings running around my engine. Oh and Lyn, if you run a heavier oil your pressure will go right up!

Edited June 3, 2013 by Mijostyn