Mongo

We aren't chemists, but I see no harm in adding less than a full bottle of the Rislone ZDDP additive. If it comes full circle, I will post a thread and tell you that you were right IF that time ever comes. I highly doubt 'adding' so little will destroy my 'cookies' in an 8-quart pan with 7oz out of an 11oz bottle of Rislone ZDDP Engine Treatment - and that is 20% of a quart, 32oz.

SeanR

Use the right oil and quit wasting money dumping additives that you have no idea if they work or not. Then again, if it makes you feel better, by all means continue doing so.

Here's the data sheets from Mobil themselves.
https://mobiloil.com/~/media/amer/us...pecs-guide.pdf

Mongo

And remove all chances of there being another oil debate thread? Where's the fun in that? /s

hacker-pschorr

This isn't really a debate

Mongo

Yes it is! You just forgot about AMSOIL! Now we just need the right person to join in and put this issue to rest

928NOOBIE

I'm using Royal Purple HPS (elevated levels of Zinc and Phosphorous) 20W 50 but before I did latest oil change I tried a container of this:

http://www.hyperlube.com/c3/zinc-rep...ditive-c7.html

I saw very noticeable reduction in vibration...this became more pronounced as rpm's went up...I wondered if the HPS had lost it's ZDDP.

A bottle treats 4-6 quarts per bottle so I decided to go for it and for this latest oil change I put 2 bottles in. My engine is happier I can tell you ...just from reduction in vibrations..especially as rpm builds....at $20 a bottle it adds $40 to your oil change costs, but with the significant improvement in smoothness for me I'm a buyer for now..even with fresh Royal Purple in there..it is still running smoother than if I just had the oil in alone.

I find I run the engine in lower gears around town and run it up higher because it feels that much smoother...it's nice.

Tomkat80222

I had my 94 GTS with 51,000 miles tested after 4500 miles and two years of use. The Mobil 15w-50 oil looks good, except the calcium level is low. I understand it's a detergent additive, but I don't know if that is an issue. I also wanted to see what the effects of two years of use would have on the oil. I found no ill effects and this may be due to living in a very dry climate. So if you are like me and don't put a lot of miles on your 928, you may want to consider extending your changes.

LexVan

You should call Blackstone (260-744-2380) and ask them to re-do your report. Your oil is a 15W50 and they think the oil is 5W40. Perhaps you filled out your paperwork wrong? Or posted wrong above?? That will effect your values. Easy fix. Good report.

Tomkat80222

I saw that and was confused. I may not have filled out the bottle correctly. I will call them to update there info.

andy-gts

hmm.....5-40w makes most sense now seeing the results