gregroselli

Had to put a quart of regular 10W-40 in my car in a pinch (was all that was available) to get it to the dealer to patch an oil leak. The original oil was Mobil sythetic. Is this a real concern or can i just ride it out till my next oil change in a few thousand miles?

Benjamin Choi

you're fine

1999Porsche911

I regularly add 1 quart of dyno oil to all my cars and boats. Better for the seals.

gregroselli

You guys are so fast its scary. Thanks. This site is excellent for new owners.

gota911

What weight of dyno oil do you add to your 15W-50 synthetic?

Wellardmac

Tim stop it!

I was almost afraid to open up this thread in fear of what I might find and here you are stirring things up again!

1999Porsche911

Whatever I have hanging around. Typically a 10W-40 since I use that in one of my boats and it's on hand. 5W30 in my lower compression, family cars.

rountreed

Oil did I hear oil!

gota911

OK Guys, you heard it here first, 1999Porsche911 stated that he uses 10W-40 in his P-car! While it may not be "Mobile Water" as he calls Mobile 10W-40 synthetic, it is a start! I guess he is a closet 10W-40 user!

1999Porsche911

For the record, Mobil Water is 0W40 and that weight is the ONLY weight oil I have strongly recommended never to be used. I have always suggested 5W40 and higher, with 15W50 being my preference for a 996. My arguement has been more against Mobil Wtaer than for another oil.

For the average 996 driver which involves starting the car, driving like and old lady for an hour, placing the transmission in neutral at al stop lights, and then speeding home at 40 mph and washing and waxing it. adding a little oil to the crankcase and then parking it back in the garage, 5W40 is fines. For those who push their cars, go with 5W50 or 15W50.

I have never stated that 10W40 shoiuld not be used.

marlinspike

What's wrong with 0w-40 if you say 5w-40 is fine? Won't 0-40 and 5-40 act similarly when hot and the only difference being that 0-40 flows better when cold? I've read of one instance where using 15-50 wouldn't let the lifters pressurize.

Blackness

Speaking of oil, I think I'm going to order this...

http://www.deandeluca.com/cgi-bin/nc...?cgrfnbr=11377

I'm over the at the moment.

1999Porsche911

Actually, it is the opposite. Lifters have more problems at startup with 0W40 that with a 15W50. Preference is to go with the 50 weight oil. Mobil 1 in general and Mobil 0W40 specifically, have a history of not protecting seals and leaking internally (burning). The 5W40 has less of burning problem, and the 15W50W all but eliminates it. If I HAD to run 0W40, I would definately add 2 quarts of dyno to aid in seal conditioning.

The push for a low viscosity oil is only to meet emmision requirements, similar in reason why you now only change oil every 20,000 miles. It it not because it is best for the engine, but it is best for the tree huggers.

As I stated earlier, a 5W40 is fine for a show car, but not for a high compression car that is aggressively driven if longevity is your goal.

Pugnacious P

1999,

You are one of the few technical gurus on this site, I am due for an oil change soon, so you think I should go with 15-50 synthetic? and not to sound dumb (maybe too late ) but what do you mean by adding "dyno" to your 0-40?

TIA

wrljet

I saw Mobil 1 0W20 at the store yesterday. Amazing.

What number is used for viscosities thinner than 0?

Bill