voskian

First time I tried Mobil 15-50W Syn in the GT. Most of the 1400 miles were highway 75-90 mph for long stretches in mostly 80-90 degree temps. Check oil level this am and down maybe less than 1/4 quart. Previous oil change was with Valvoline VR1 20-50W racing oil and it burned thru much faster.

AC was on most all the time and car averaged ~ 18 MPG

Love this car!

SeanR

That's what I put in 90% of the cars that I work on, the other 10% are the boutique oils. I'm happy with the results in them.

linderpat

Thanks for that data point Bob. I always shied away because it seemed to leak out from underneath, and other brands didn't. I've been using Royal Purple in Blumaxx with very good results. Maybe I'll try the M1 in the garnet red car.

It was great to see you, and hopefully we'll see you at Frenzy!

77tony

hmmm....and Stan suggested to use VR-1 to prevent the cam seals from leaking. T

SeanR

Never understood why people still believe the myth that Synthetics are not good for our cars. If the synthetics are doing their job, which is keeping the internals clean on the car, the only thing that was keeping your engine from leaking was goo and dirt.

I keep seeing one 928 "expert" tell people all over Facebook that they are going to hurt their car using synthetics because it wasn't designed to use it. LOL. That amount of retardation is amazing.

GeorgeM

I've had similar results, Bob. I switched from BP to M1 about 5k miles ago and have noticed less consumption - like no decrease on the dipstick at all during this trip, about 1100 miles total.

I switched mostly due to cold starts. BP is so thick, especially when it's cold. Although it doesn't get that cold here in Va Beach, we were on a trip to NC a while back and it got chilly with some freezing rain. The AM startup was not pleasant to hear. I'm sure things were ok, but it didn't sound very nice for the first 5 seconds.

I have no leaks from switching, nor have I noticed any difference in oil pressure.

My conditions were similar to yours this weekend, and I saw the best mileage I think I ever have in this car, 21 mpg, and I was using the a/c much of the time.

I know BP is a great oil and I still use it in my 911 and GTI.

Not that I'd ever base the health of my GT on convenience or saving a few bucks, but it is also nice to be able to scoot down the street to the local WM and get the M1 for $25/jug.

dr bob

My car has been using M1 since I got it almost 100k ago now. All the cars in my garage use it, plus all the powered toys and tools. It's readily available, relatively inexpensive in the giant scheme of things, etc. Based on some inspection data, it's doing its job quite well. Rod bearings in the 928 looked great at 110k. Bores look great too. On a previous car that enjoyed M1 from shortly after birth (drove it home from the dealership and immediately swapped all fluids), the internals looked as-new when headgaskets were replaced at a little over 100k (a Prestone coolant related failure). There was no ridge in the bores, original honing hashmarks were still prominent, and all the oiled sections were free of any varnish or deposits.

On the 928, I replaced the oil sump gasket in November, after finding a dime-sized ocean of oil under the car after the previous winter's hibernation. Those gaskets should last longer than 28 years. Oh well...

MainePorsche

M1 is all I've used, and I've never had an issue.

Gary Knox

I too used Mobil 1 15W50 in every one of the six 928's I owned from 1998 through 2015. Several of them were driven in the Porsche Drivers Ed (Track) events. On the track, I found about 1 qt of consumption in 150 or so miles (mostly at full throttle. On highway/street driving, my experience was about 1/2 PINT consumed in a year (5-6K miles). Only long trip in the '94 GTS was to Denver and back for the OCIC, ~3500 miles - summer through the great plains! About 1/2 pint for that trip.

All four cars in the garages here, including the '74 model in the avatar have M1 in the crankcase.

Gary