Bill Wagner

Several years ago when I was overhauling my old MR2, I told one of the guys remachining the heads that when it was done I was going to switch from dino to synthetic. He told me he thought that for a car of that age and mileage it would be a waste of money because the synthetics tended to burn more. I kind of blew his comments off.

After he told me this, I switched from dino to synthetic on my old Stealth RT/TT and noticed it was drinking about 1/2 quart every 3000 miles, when it hadn't been drinking any before. Recently, I switched my 300ZX from dino to synthetic, and sure enough, at about 2000 miles on the oil change it was down about 1/2 quart. It NEVER lost any oil when using dino. All of the Japanese cars I've mentioned were using 10W-30.

Currently, my low mileage '91 C4 (now at 21.5K, 18K when I bought it) isn't consuming much oil at all (I FINALLY had to add 1/4 of a quart a few weeks ago) but it is using dino. I noticed in one of the posts below that someone was using about 1 quart/1500 miles (Jeff C.) with Mobil 1. Granted, his mileage is higher than mine, but is the higher consumption a characteristic of synthetics? Was the machinist really right?

Just curious,

Bill Wagner

P.S. I have no doubt that the synthetic oils are probably better lubricants than dino, I'm just curious.

Adrian

Dear Bill,
This question is often asked and I know you will get many, many, many, differing views and opinions and stories.
For the record,
My 1989 K series 911C4 has always had Full Synthetic Oil, currently running Mobil One 5W 30 (all season, cold climates). I use approximately one litre of oil per 15,000klms. I have currently have 136,000klms on the clock. I change my oil every 20,000klms.
In my 944 I changed the oil from Castrol Dino to Castrol synthetic 5W 30. I have not used a drop in the past 2000klms since the change. No leaks no nothing. My 944 is a 1985.5 model.
Just my experiences. I have heard all the tales before and instead of trying to argue with people I just say, use what you are comfortable with,
Ciao,
Adrian
911C4
944

Bill Wagner

Interesting.

If you notice, my own experience with synthetics has been with Japanese cars. Perhaps this says something about them.

Cheers,

Bill Wagner

Adrian

Dear Bill,
Yes I did notice but you mentioned Jeff and his 964 and I have heard the same from many other Porsch owners who either sincerely believe that synthetics oils cause leaks and higher consumption or have been told by others this and they have not questioned it.
The Japanese have produced some brilliant autos over the years. I am a complete car nut from any place on the planet. I love the whole topic so I do not run or imply to run anything down certainly not by nationality.
Hop in a Nissan Skyline GTR andf take it for a spin. Or a Turbo Subaru Impreza. Impressive. Originally tuned by Porsche by the way,
Ciao,
Adrian
911C4

Bill Wagner

Adrian:

I didn't mean to imply that the Japanese cars were bad. All three of mine that I've used synthetic with used similar weight oils (0W-30 up to may 15W-45, but typically 10W-30) and were radiator cooled. My curiousity was whether or not this type of engine in some way tended to consume more synthetic (probably not a topic for this board at this point) due to things like manufacturing tolerances.

Cheers

Bill Wagner

1AS

I havn't switched my high mileage 91 C4(93,000) due to an experience I had with a vintage race car. I had no problem when I switched on my 94 BMW and 96 Landcruiser. Bolstered by that, I switched a V8 engined vintage racer to Mobil 1 and watched the oil leak out everywhere. It's definitely slipperier. This is an experience I don't want to have with my C4.

1AS

I havn't switched my high mileage 91 C4(93,000) due to an experience I had with a vintage race car. I had no problem when I switched on my 94 BMW and 96 Landcruiser. Bolstered by that, I switched a V8 engined vintage racer to Mobil 1 and watched the oil leak out everywhere. It's definitely slipperier. This is an experience I don't want to have with my C4.