I don't understand why someone living in Bakersfield would even consider buying 10-W-30 for any vehicle.

Waaay too light for those high ambient temps.

 

It is early I misread the synthetic oil weight , 30 W is really a bit thin for high heat. So I change my vote ! Mixing oils is fine 30 W is marginal. Will it hurt the engine ? probably not . Note Porsche said straight 30 W was OK but multi grades were best.

 

I would just buy some engine cleaning treatment and add it in, run it to let it warm up per instructions that come with the cleaner and drain. Might as well use it to clean the all the old grime out of your system instead of just draining and wasting it.

 

Erik--

The key symptom you'll be loooking at is hot idle oil pressure. Oil that's too thin won't maintain the 1.5-2 bar minimum you would like to see. Drive it too work, drive it to Glendale on Friday. If you see drooping hot idle pressures that make you nervous, plan on changing it again in the next month or so, before you start seeing 90+ hot day temps.

I suspect you'll be fine on all but the hottest days with what you have in there. As JB points out, Porsche recommends 30wt for summer use if you don't have a multi-weight available. That tells me the xW-30 should be OK, since the hot film stregth is comparable. Nonetheless, the lower actual viscosity will surely cause hot idle pressure to droop. How much? Depends on how well your radiator and oil cooler are performing.

If you see that oil pressure isn't meeting your expectations, there's a filter or three on the shelf here, a gallon or three of M1 15W-50 here, and a giant ziplock bag you can use to take your old oil home in. I don't win oil filters as aften as Nicole does, but I do stock a few just-in-case.

Your Mileage May Vary, but that's my advice. Perhaps oil guru Doug Hillary will pop in with an opinion too.

 

As long as the oils meet Porsche's requirements, you are OK. I use Doug Hillary's recommendation of an oil with HTHS (High-Temperature, High-Shear) viscosity above the Porsche minimum of 3.5cSt. You can usually find that spec on the oil manufacturer's website.

A 10W30 synthetic is probably OK for high temperature.

 

While half my gut says that mixing won't be a short-term problem, i.e. until the next oil & filter change, the other half of my gut asks 2 questions:

How much is an oil & filter change (around $50-70)?

How much is an ENGINE change (slightly more than $50-70)?

 

You're right!! I'll get right on it.

Very true. The good news is that it is not hot YET.

Man, you guys are AWESOME!! And here I was worried 'bout mixing synthetic and conventional. Sooooo, basicly what i'm getting is that I F'd it up good, but will be OK for a short time. I'm going to San Diego tomorrow (goin' karting, ya know), but I think I will definetly change it on Monday. Thanks again for all your GREAT input. You guys are invaluble.

 

I dont think you run that much more of a risk for engine meltdown by running this mixed up stuff for the time being.

Its not IDEAL, and not what any of us would recommend, but I dont think its really a cause for too much concern. I think you'll be fine for the time being but if you are sitting at home at night wondering then just change it out for nothing more then piece of mind.

 

Mixing oils is no problem and being synthetic the somewhat light weight oil still more than meets the required standards. As Dr. Bob pointed out on a hot engine on a hot day at idle the pressure might get a bit low....and seeing the flashing oil presure light is not comfortable for most. The old very brown 1980 at the Streets on a 105 degree day after grinding around in mostly second gear often had low oil pressure...at idle So I just step on the GAS

 

This is turning into a Master Card commercial...

Oil & filter change... $60

Engine Change... $7500

Piece of mind... priceless

 

I assume this was your first oil change?

I guess if it bothers you just replace it, try and put the drained oil in something else. Chock it up to inexperience and learn in the future that oil changes take between 8-9 quarts.

 

Engine oil volume.. approx 7.5 liters plus .5 liters when replacing filter..amount of oil between Min and Max approx 1.5 liters..

 

hey jim good point, this reminds me of a post PorKen had about oil consumption going up when you have the oil at the high side of the fill mark. He runs it at the low end and apparently oil consumption through the intake is reduced significantly. I think I may try this and just pour in 8 quarts event though i have 9.

 

Rightous brother!!

I wish it was. I might not feel like such a schmuck. Come early next week, i'm changing it..........CORRECTLY!!

 

uh oh, you should know better then to only buy 6 quarts