glaffy

Hi

Just a quick question: Can Rennlisters recommend a good engine oil for the 930 (needs to be available in the UK)? I'm driving the car much more than I thought I would since buying it in May (almost 2,000 miles now) and, as the car has 99,980 miles on the clock, I expect it needs an oil that reflects the age of the engine.


I can't say how much I'm enjoying the car, apart from aquaplaning at 60mph the other weekend on the M4 - the weather in the UK has been truly awful.

Glaffy

Chuck Jones

There are many, many threads on this...if you do an archive search you'll see a lot of folks use the GTX 20-50 and are satisfied.....hopefully this wont' end up in a ten page dissertation.

HkPlinker

My 88 has 75k miles. I ran a synthetic blend for a few months just after I bought the car and went to Mobile One 20-50. It drips one or two drops after everytime I drive the car, but that's it. I have been running it for two years now. The benifits of Mobile 1 pure synthetic far outweigh the possibility of leaks, period.

pdqcarrera

I've never understood how/why supposedly a synthetic oil would leak more than a mineral based oil if they're both the same viscosity rating. Viscosity is a measurement of an oils ability to flow. As long as 2 fluids/oils are the same viscosity they will have the same resistance to flow. At the molecular level synthetics are different for the purpose of improved adhesion to the surfaces they're protecting, and increased stability & resistance to being broken down (resistance to sheer), etc...

sand_man

I used Castrol GTX 20W-50 for my engine rebuild "break-in" and then switched to Shell Rotella "T" Synthetic 5W-40 (stuff commonly used in diesels) and have been VERY happy! No leaks (new engine, though), not too expensive, warms up nicely, and never crosses the middle line in the temp guage...usually stays a c_nt hair below it.

I did try the Rotella dino based 15W-40 and also the Mobil Delvac dino based 15W-40, but their formulas have recently changed and offer lower Zinc (Zn?) levels, which I'm told aircooled engines like.

Lots of folks use the Mobil 1 15W-50 with good results. Brad Penn, Royal Purple, Harley Davidson brand have all been used with good results.

sand_man

Some good reading for you:
http://www.lnengineering.com/oil.html

DonE

Synthetics have a much higher intrinsic ability to clean (specifically the polyester base) vs mineral based oil. They also have the ability to seep into areas such as old gaskets on high mileage engines.

nathanUK '81 930 G50

Yep, I think the synth cleans up the engine and unblocks any dirt plugging holes causing a leak.

It has been said that synth is better for the turbocharger, not the actual engine itself.

I got some Mobil 1 15-50 Motorsport formula oil. If I couldn't get hold of that then Royal Purple would be a good choice.

All this is IMO.

stu.p

i have always used 10/40 semi syth on both my 911 turbos,,,seems fine with no issues

glaffy

Many thanks for all the replies. Given the high mileage (100,000), I'll probably use a 20W-50 and see what happens. I'll post pics of my gold bullet soon...

dholling13

I am a Redline Oil man (Imagine Auto). Don't know about availability across the pond? Mobil lowered zinc levels in hopes of keeping cats from clogging. This is great if you don't have an air cooled car. I also like Motul's products, I will be putting their straight 90 for LSD's in my tranny after the track season. Motul has a really nice high end oil that is made from vegetable oils. Just some of my thoughts... Good luck!

Sand_man- My oil temp does go over 1/2 half way, but only at the track in 90+ degree temps but as soon as I hit the cool down lap, it drops back below half way.

Nape75'911T

20 W 50.....no issues.

Don't know about availability for you though....sorry.

nathanUK '81 930 G50

I am sure we can get that here in UK.

spuggy

Be aware that some oils - Mobil 1, for example - is a different formulation in Europe, with the same packaging. There was a thread on PP that mentioned this about 6-9 months ago. IIRC, Europe gets the full synthetic version, whereas the US one went to dino base.

It's all very well to say that the synth oils are better for the turbo than the motor - and this may be true - but remember that eventually all the oil will go through both, and one of these gets very hot, and the other sometimes gets frickin' scary hot (ever looked at the headers and the wastegate dump when your car is being dyno'd? Ha!)

I've never looked, but I'm told the oil collected in the turbo drip tank looks like crema from an espresso machine before it gets returned to the tank (crema is that frothy light brown foam)...

I like the idea of Rotella T - diesels are extreme pressure and heat applications, often turboed. My wrenches use that, in rotation with Texaco Havoline.

My thinking is that there may well be oils that suit air-cooled motors better than water-cooled - and turbos are a very high heat application. I wouldn't settle for anything less than a good-quality, brand name fully-synthetic for a 930 - given where dino oils break down and the temperatures inside a 930, just think of this as another area that's moved a long way in 30 years.

It also seems to be a good idea to consider the factory oil change interval as overly optimistic and do it more frequently.

sand_man

mmmmm, espresso! I think I'll make some now <<grabs keys to the 930>>!