924Board.org

[J.P.]

Ok, so its been a while since I owned a car that used the oil that my 1987 924S uses. I run Mobil 1 15w50 in my Mazda 323 GTX turbo, and I have 5L of that in the garage (the GTX has been parked for a few years). Looking around at the local parts stores, I notice that the options are pretty slim when it comes to 20w50 in my area.

After searching my local suppliers, I have found the following options:

Mobil 1 15W50
Castrol GTX 20W50
Royal Purple 20W50

I have service history on the car (160000km +/-), but no receipts showing the brand of oil that the garage used. Judging by the price of the oil changes on the invoices, it was not synthetic. Whatever I go with, I would like to stick with. The car will be garaged over the winter, so I am not worried about cold weather performance.
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1987 924S

[bcblase]

Castrol GTX 20W50 = $13.50 for 5 liters at the local Wal-Mart.

I run that in my 924S track car all year round.

It hasn't failed me yet...
_________________
1987 Porsche 924S - track toy
1986 Mercedes 190E 2.3-16v - autocross
2007 F-150 5.4L Lariat Supercrew - tow beast
1994 Volvo 850 Race Wagon - 24 Hours of Lemons Car
2001 BMW 325xi - daily driver

[TJC]

Mobil 1 5W30 or 40.
Adequate oil pressure and good fuel mileage. Ambient temperature range from 20 degrees F to 100 degrees.
If you take a look at the owner's manual it is considered as "Fuel Efficient" type.

If you decide to use a synthetic, you may want to keep an eye out for leaks and change it sooner than you normally would if you believe that your car may have had "dino" oil in it.

Mobil 1 is also my choice for "Pearl", but I currently use Castrol 20W50 GTX in "Happy" as I feel it works well in an ACVW.

By the way, if you can only get 15W50, I don't think your engine will suffer from it's use.
_________________
'95 BMW 318i/5 ..."Pearl"
'87 Porsche 944 NA... "Liebchen"
'02 Porsche Boxster..."Sunbeam"
'04 BMW X3..."Xander"
Still on the Prowl!

www.ttrs1.com

[joecitizennn]

I have been a mobil 1 fan for several years, but I have come to learn that they are using group III oils (dino based) as a base for their products rather than group IV and V oils. This may explain why walmart is carrying the stuff. It is cheapened so Fag-Mart can sell it and you are buying the name. Yeehaw
_________________
87 924s
88 924SE gone
447 hp cgt clone
87 924S gone
84 944 sold
83 944 sold
89 turbo S LSD, ABS etc
86 951 white rocket
85 944 sport everything.
84 944 sold.
87 944 sold

[bcblase]

I won a case of this stuff at our holiday party - 4 gallons is worth well over $100.

Liqui-Moly or Lubro-Moly Full Synthetic Oil - "made in Germany"

http://www.liqui-moly.de/liquimoly/web.nsf/id/pa_eng_home.html

I'll probably try it this spring...heck, it was free!
_________________
1987 Porsche 924S - track toy
1986 Mercedes 190E 2.3-16v - autocross
2007 F-150 5.4L Lariat Supercrew - tow beast
1994 Volvo 850 Race Wagon - 24 Hours of Lemons Car
2001 BMW 325xi - daily driver

[J.P.]

Thanks for the replies. I think I will go with the Mobil 1 15W50 that I have, and monitor leaks. My commute is all highway, its the Sundays at the local auto-x that I would be more concerned about.

For the transmission, they also have Mobil 1 75w90 gear oil that I think i will try. I'm assuming by what it shows in the manual that it would be suitable (80w gl-4). I have used Redline in both of my other cars (tranny only) for years, and had good results, but I have not tried Mobil 1 gear oil before.

Other fluid changes planned:
1. Coolant - Prestone LL Dexcool - or Honda OEM coolant (undecided - I have both)
2. Power steering - Mobil 1 synthetic ATF
3. Brake fluid - Valvoline synthetic DOT4
_________________
1987 924S

[Paul]

If the car has been running dino oil, stick with it. Oil leaks are expensive on these motors.
_________________
White 87 924S "Ghost"
Silver 98 986 3.6l 320 HP "Frank N Stein"
White 01 986 "Christine"
Polar Silver 02 996TT. "Turbo"
Owned and repaired 924s since 1977
Porsche: It's not driving, it's therapy.

[joecitizennn]

I didnt notice any additional leakage when I switched to full synthetic but every situation is different. If you have not done the front engine service, that should be a priority, and you can make sure to replace the front engine seals when you do. I would rather run something good in my engine and replace the seals than cripple along on canola oil to prolong the inevidable maintenance of seal replacement.
_________________
87 924s
88 924SE gone
447 hp cgt clone
87 924S gone
84 944 sold
83 944 sold
89 turbo S LSD, ABS etc
86 951 white rocket
85 944 sport everything.
84 944 sold.
87 944 sold

[J.P.]

The timing belt was just done by the previous owner, and I have the receipt from it. Synthetics have that rep, but I am not worried. I bought a Honda Civic that had run on dealer dino for 15 years, and 96000km. I found it was using some oil, and decided to try Mobil 1. I am now over 140000km, and it's not using any oil now. So like you say, every case is different.

It is a similar thing with Dexcool. Some say it can be problematic, but I have used it (Prestone Dexcool) in cars as replacement coolant for years, and it works well for me. That said, I still wonder if the Honda coolant would be a better choice for the 924. I work for Honda, so I get it at a good price.
_________________
1987 924S

[bcblase]

FWIW, here's what I use:

Motor Oil: Castrol GTX 20W50
Coolant: Preston Dexcool (orange phosphate free stuff)
Brake Fluid: ATE Blue (racing grade)
Tranny Oil: Swepco 201
Steering: None, manual rack

If you can afford the Swepco, that is some good stuff. You
don't have to change it very often, and well worth the money.
_________________
1987 Porsche 924S - track toy
1986 Mercedes 190E 2.3-16v - autocross
2007 F-150 5.4L Lariat Supercrew - tow beast
1994 Volvo 850 Race Wagon - 24 Hours of Lemons Car
2001 BMW 325xi - daily driver

[stevekat]

I use Mobil 1 in my 931 to prevent coking of the turbo bearings. However in my 1994 S38 B38 M5 3.8L I have been using non-synthetic Kendall GT, but now am moving over to Brad Penn at a new oil change this coming week after reading about it (it is the old Kendall GT formula made at the same prior facility after the Kendall brand was sold.) Frank Fahey in San Diego insisted on Kendall GT is my M5. He refused to put in synthetic. Now Brad Penn is the equivalent. Google Charles Navarro and Oil and you shall get some background and data.
_________________
"Never get out of the boat. Absolutely goddamn right. Unless you are goin' all the way."

Gone to new home: '81 924T, US version, CGT Intercooler, UTCIS-PT, Euro DITC, Greddy Trust MBC, Forged Fuchs Flat Dish 6's, Factory Recaro's.

[Paul]

I can remember at least 5 owners whose cars that I have worked on that when they switched from dino oil, oil leaks developed within a month or so. Usually its the cam box gasket, but I've also seen balance shaft seal leaks and oil cooler seal leaks (causes oil/coolant mixing).

Not worth the risk, these motors will run 250,000 miles on dino oil with regular changes.
_________________
White 87 924S "Ghost"
Silver 98 986 3.6l 320 HP "Frank N Stein"
White 01 986 "Christine"
Polar Silver 02 996TT. "Turbo"
Owned and repaired 924s since 1977
Porsche: It's not driving, it's therapy.