JBD3482

I know what you guys are thinking....not another oil question. I've done some searching and haven't really found a good answer to my question. I just put RP in my car a few weeks ago, but I've been reading some pretty bad stuff about it. I'm thinking about switching to Mobil 1 in my next change. Is it okay to switch between oils? I read that RP has it's own additives, and didn't know if that would interfere with the Mobil 1.

Thanks

Burnsy

yes, its okay to switch.

Nuke

There should be no compatibility issue. Just be sure to drain as much as possible. Whatever is left will be such a small fraction of the total volume that it wouldn't be a concern even if they weren't compatible.

Argonaut

For every detractor of Royal Purple you will find just as many promoters. 99% of what you read is simply opinion. You should develop your own opinion based on real lab test results, race track results and the experience of folks who build an operate engines for a living. Like the others said, you can switch and Mobil 1 is a good oil (as are many others) but before doing so why don't you get tests done for yourself. Put 3-5K on you car using RP and then send a sample of it into Blackstone Labs for analysis. This will give you the real answer on how well its protecting your motor.

Disclosure - I don't use RP, I use Mobil 1 and I have had it tested twice with excellent results. I just wanted to point out that the internet is far more about opinion and very little about fact, especially when it comes to oil.

JBD3482

Thanks Argonaut. I was just reading anout the moly in RP clogging oil passages and causing other issues. I only saw that in one place, and after reading further I saw that the article said that this was possible on extended periods without oil changes. The other thing I saw was that RP had a low flashpoint. Of course I went and looked at their actual specs and the 5W-20 is 455. You're right, it's almost all based on opinion. I think I'm going to stick with RP and send in a sample. Thanks again.

moosestang

Can you pm me the results or post them here? I'm having mine tested and would like a similar car for comparison. I also use mobil 1.

ffk_pennywise

I'm interested in M1 results, too. I just changed my first batch of Mobile 1 after 10k miles. It looked a hell of a lot better than motorcraft does after 5k! Not very scientific, but it made me feel good. lol.

Nuke

Visually "black" oil does NOT indicate its condition. Motor oil will turn black within the first few hundred miles. And those that have cut open their oil filter and reported that it was trashed because it was black are also misinformed. A good lab can test the oil for metals, acids, condition of the additive packages, etc.. If we were to change our oil because it was "black" we'd be broke.

Lab analysis is great for trending purposes and a wonderful Predictive Maintenance tool but still can't always prevent a catastrophic failure, especially as a stand alone technique.

Jbauer

IF you want to see how it does in your car, google blackstone labratories and send your oil in to them.

imho, RP is junk and people only like it because it's purple..funny, but i really believe that. I don't think i've ever heard of RP having a problem with moly though. If anything i don't think it has enough. Redline has plenty of moly and its a decent preformer, even on the race track.
The thing with RP that i have noticed is that it doens't like being switched.. if you switch to mobil 1, your oil analysis may yield poor results because of the additives between mobil 1 and RP clashing. Mobil 1 itself also doesn't like being changed either, something to do with the sulfur i think it was.
In either case, from What i've seen; both Mobil 1 AND RP are Poor preformers considering whats out there. I'd go with any synthetic oil on the market but those 2.

Argonaut

Moose - here is the link to my post on the results of my latest Mobile 1 oil analysis: https://mustangforums.com/forum/2005...s-results.html