My car is a '95 with an '00 engine that had 41k miles on it at the time I swapped it in. I did the initial fill with Amsoil Series 2000 0w-30 and an Ea oil filter. I had been intending to try to stretch 10k miles, but as I approached 8,000 I noticed some slight roughness from the engine, so I decided to do a flush and change on Friday. Did the flush with Amsoil engine flush and a Wix filter, re-filled with Series 2000 0w-30 and added another Ea filter, and it's as good as new. Oil consumption was very, very small.

So, here's what I'm wondering: Since I don't feel like waiting until I start to get tangible roughness again, is it fair to say that 7500 miles is a good OCI for this engine with this oil and filter? Or, is it likely that I was being limited by deposits that had formed in the engine while it sat in the junkyard before I got it, and that since a lot of those deposits have now been washed away, I can therefore go longer before my next oil change?

Informed opinions greatly appreciated!

 

Who knows? If I bought an engine that had been sitting in a junkyard, the first thing I would do is an AutoRX application.

See www.auto-rx.com and the Additives forum at BITOG (www.bobistheoilguy.com).

Don't overextend the initial OCI of a long dormant engine.

 

Good advice. In your case, I would have started with dino oil for the first two changes, at about 3 K miles each -- before going to synthetic.

 

Great. So... What do I do now that I already have overextended the OCI once, didn't run AutoRX, and used synthetic already?

BTW, I don't think it was "long dormant"... A couple of months maybe.

 

There are plenty of posts on this site and other sites (BobTheOilChangeGuy) that confirm that 10 K miles OCI on Synthetic is not a problem. In your case, you started with an engine that had been sitting in a junk yard for an unknown lenght of time and had unknown oil changes by the first owner, with the potential of building up gunk in the oil system.

You are where you are. IMHO: You are continuing to use Synthetic -- that's OK. Do your next oil change at about 5 K miles, do the second (synthetic) at 7.5 K miles and send in an oil sample for testing (see stickies for details on this). Depending upon the results of the test, further adjust your OCI, possibly going up to 10 K miles.

In the event that you don't put many miles on this engine, I would not run the oil longer than about 6 months for the next two changes, with the test after the second change.

 

Thanks! I drive about 30k a year and I'm not shy with the gas pedal, if that means anything.

I'll keep the next couple of OCIs shorter. Would you recommend flushes at those oil changes as well?

 

Does this mean that you frequently accelerate quickly from stop lights? Or does it mean that you do a lot of highway driving at high speed? If you do a lot of stop and go driving, that is hard on the motor oil (along with driving in dusty conditions) and means that you change your oil more frequently. With a lot of highway driving (even at speeds up to about 90 MPH), that is easy on the oil and means that you can increase the OCI.

I would not recommend a flush (one or two), but suspect that Bobo would recommend at least one.

 

Most of my driving is highway driving, but I am fairly aggressive... I take off from stops quicker than most people, I end up using WOT up to fairly high RPMs at least momentarily on most merges and onramps, I have no reservations about covering clear ground ahead of me to the extent that I can without dropping down two gears and redlining all the way back up, and so on.

 

So long as you are not doing a lot of stop and go driving, you should be OK.

Should have mentioned that the highway driving needs to be for at least 30 minutes or more (before you turn the engine off) to properly warm the engine. So long as you do that, a longer OCI should work out just fine for your driving style. Motor oil works best when it and the engine are hot, so short trips are hard on the oil, requiring that it be replaced sooner. (It also does not like dust and blowing dirt).

 

I think you'll be okay. You would have been better off doing the flush before switching to the Series 2000, but you can't change that now. By running AMSOIL and the premium filter for 8K then the flush, you have probably cleaned out a good portion of any deposits that were there. Recommend you run your current fill for ~7500 miles, then do an oil analysis to see where you are at...base your future OCI decision on the analysis. You can run the AMSOIL flush thru the engine at the next few oil changes if you feel its needed.