s4bill

"For a 928 a synthetic 5w-40 “mixed fleet” Heavy Duty Engine Oil (HDEO) is probably the best choice of all and far exceeds the A3/B3 or A3/B4 ratings"

Is this what you are using?

Rob Edwards

For a year I had Shell Rotella 15W-40 in my GT, per one of Doug Hillary's oil threads. It did not like it when stuck in traffic, at 90+ degrees, triggered the oil pressure warning (albeit on a '90, with no oil cooler in the radiator..) How hot is it in Maryland today?

polecat702

Royal Purple 10/40. Expensive, but so far zero problems.

s4bill

It is 100 in the city. It is predicted to reach 108 on Saturday.

My AC is not working in the car. That is a separate thread.

Rob Edwards

FWIW, in a driving season that ranges from 50 to 105oF, I like Torco TR-1 20W-50.

UKKid35

Penrite HPR15 - no more oil pressure issues even on hot trackdays. Car is usually laid up in the winter.

s4bill

That is the reason I ask. I thought for sure someone (or maybe even a consesus) on one of these forums suggested that I use 20w 50 Mobile 1 synthetic.

I am going to change the oil shortly and want to do what is best.

Ducman82

Castrol 20w50 here. till this motor is broken in then Mobile or Redline.... what ever is local.

deutschmick

Mobil 1 15W-50. It's not tracked, but has seen some 110+ days in Phoenix stop-n-go traffic. No oil pressure problems so far. I wish I had an oil temp. gauge though.

mickster

Ditto. About $25/5 quarts at Wally-mart. On Special now at $6/quart at NAPA (no bargain).

auzivision

M1 15/50 once a year (less than 10K miles... maybe less than 5K lately).

Thanks for the reminder, I'm due now

Bilal928S4

I have always used Castrol 20W50. When I did my oil pan gasket and had a peek inside it was very clean. The car had 118K and is the 90S4.

s4bill

Now that it is mentioned several times. I think it was 15w 50. This is the reason why I ask.

Everyone loves Wally world.

What are the pros and cons of using 15w 50 vs 20w 50?

redpathtribe

Another vote for Mobil 1 15-50. Have been using it for 12 years, including track days and auto-x, never had any issues. That's in Phoenix, so it does get a little warm here...

I think most dino oils are 20W/50 and synthetics are 15W/50. I'm sure most dino oils in that weight would be fine for normal street use, you'd just have to change it more often. I use a synthetic because of the high heat in Phoenix and my 928 is a daily driver.

jetrainor

Use 15-50 Royal Purple.....some of my hot-rod buddies claim i'm losing 'big' HP with the 50 end of it...