Since I had my engine rebuilt/ Turbo'd in 1999, I have been using Mobil 1 15w50 EP without any problems at all. My mechanic just told me, after running the car for about a month, that he put in Castrol non-synthetic oil. I was aggravated, so I did not even hear the weight......

So my questions are: Is there anything special I should do prior to changing back? Should I add any "special" additive/ product prior to the change that will help clean out the old oil?

TIA,
Miles

 

What weight is the Castrol? Personally, I would leave it in there but not go over 3K miles.

Theoretically, if you empty the pan of the old oil you should be able to switch back no problem. At least that's what mechanics told you when everyone went with synthetic 15 years ago.

 

I have read quite a bit about this "Z-something" additive, and that you can buy it & add to your synthetic oil --- vs. using Redline or Royal Purple synthetic oils which both have this necessary additive already added.

 

No, you don't have to do anything special. Just change it back at the next oil change. You haven't hurt anything - they're compatible.

 

It make sense now......The engine had sat drained of oil for about 2 years....The mechanic used the cheaper oil and pre-lubed the pistons etc. before restarting it. He knew the oil would only be used for a short "re-break-in" period before being changed again. I was just worried about the mixing of the two oils but since they are compatable, thanks CurtP, I have nothing to worry about. I am thinking the first Mobil 1 change interval wil be shortened too..

Thanks again!

 

The mechanic did it right. That is a very good break in oil. One of my mechanics uses it always but I do not.

 

I agree. When I rebuilt my '95 engine I did the same thing. The rings seated very quickly and the engine runs amazingly. Then I switched to my favorite synthetic.

Technically, by changing the oil, you won't get all the old oil out (the oil cooler for example hold a lot of oil). But it's perfectly fine to mix a little bit of the cheap stuff with the expensive stuff.

 

^^ Looks like the OP's engine was rebuilt in '99 (not 2009)

You can drain the oil and fill her up with synthetic as soon, or as late, as you want.

 

At the 968 reunion at Hershey, we went to Don Hassenbein's house and watched a video from Tom Chadsworth (PCA Tech Chair 968). He told us not to use Mobil 1 anymore because of the formula change 3 years ago. That many engine failures occurred after the formula change do to the removal of zinc and something else. He recommended Royal Purple or other racing oil. I actually bought some Valvoline Racing 10 w 30 oil today.

 

zddp was taken out of most popular oils at the urge of the auto companies so that emissions parts will meet the distance to failure requirements imposed by the department of transportation. At the same time, mobil 1 stopped making pure synthetic oil. I switched to redline in my 968 at this time and I noticed my valvetrain got a bit quieter. I've been running redline in both my p-cars since.

 

So what oil are you guys running these days? I noticed Redline sells a zddp additive, but since my engine is already broken in, I don't think I need it? I am considering Royal Purple or Redline, any other recomendations out there?

 

I recently switched to Total (ELF). I will report on how it's working out. From everything I have read and seen, its an excellent oil for European cars. I have been using it in my BMW's and Audi with great success.
Raj

 

Hey Raj,
Are you running Total in your Turbo as well? If so, what weight is it?
TIA,
Miles

 

Miles - S&G on 8 Mile stocks the Total oil. I've been using the 5-W40 since it meets the current Porsche spec.

 

Thanks John!
I will check them out