CarAndDriver

Now that my car is going out of the bumper to bumper warranty, I am thinking of switching to a full-synthetic motor oil.

1. What do synthetic users recommend? 6000 miles (2X dino)? 7500?

2. Has anyone used AMSOIL XL Synth 10W-40 or AMSOIL Premium Synth 10W-40?

I searched and most of the discussion was around dino oil intervals. Many people use RP synthetic, which I am also considering.

CarAndDriver

Any recommendations on synthetic oil change interval?

ken-x8

Odd that you haven't gotten any replies.

I'm a dino user, but from spending too much time here I get the impression that synthetic users change at the same intervals as dino.

Why switch away from Mazda's rules when the B to B ends? The one where oil matters is the 100K engine warranty.

Ken

WiredAnt1

I use Amsoil 5w20 XL. I just did my first oil change with AMSOIL and I ran 5000 miles. The oil still looked fairly new. Keep in mind, that when I did the change I did not empty the oil coolers, which left a lot of the older oil in. My oil was still clear enough to see the red and not all black. I am going on my second change now and I put AMSOIL back in. I also changed all the fluids (tranny, diff, etc.) with Amsoil as well and gained +2-3mpg pending on driving habits. I talked with my rep and he called Amsoil and they confirmed that there is not a racing oil they can recommend because of Mazda, however if you look on their site they have the 5w20 listed and he said that the 5w30 long life (25000 miles) would work, but they can't warranty it because of the agreement with Mazda. So I stayed with the 7500 and was done with it. He did say that a good filter will be needed. I used the PureOne filters, but the high end Wicks or K&N's would work. Amsoil said that the filters tend to fail around 5000, unless you get the higher end ones.

mpsii

^^ Good info.. I have read so much on here about oil, it is sad. If the synthetics will get me longer between changes (even with the topping off), I may use them.

My only real concern is the cost.. since I am topping off after every 2-3 gas fillups, will the advantage of synthetic help me at all?

deadphoenix52

i still do every 3000

ndhoffma

Maybe take it out at 3000 & send it to blackstone labs to have them let you know what the oil looks like... they can analyze the condition of it (what additives are still left, how clean it is etc) and let you know if it looks like you could run it longer.

Although for warranty I think you still need to do it every 3k... if the motor craps out, it'd be worth the extra oil cost to change every 3k

trustbuddy

iTrader: (3)

when I used to use amsoil, i wasn't sure about their longer change interval claims, since our cars have about 30% of the old oil in the coolers and lines. I emailed them regarding the issue and the reply was that they don't recommend the longer interval even though they sell 25,000 mile interval ones. They advised that I should stick with the manufacturers recommendation. So..I swiched to mobil 1 which is about half the price from the local walmart, and change it every 5000. I think I can dig up my old email... hold on..


this was my question:

Hello. I currently drive a 2006 Mazda Rx-8 6mt. I have been using amsoil 100% Synthetic 5W-30 Motor Oil (ASL) with Eao 12 filter for the last couple years. One thing with the renesis rotary engine is that it has oil coolers. So when I change the oil, about 30~40% of the old oil is still within the oil cooler and the lines. with such situation, do you still recommend the one year/15000mile change interval or a shorter/frequent change term. One other thing with the renesis rotary engine is that it is designed to consume oil so i am adding oil (about 1/4 quart) about every 2000 miles. any input would be appreciated. Thank you.



the answer:
You will want to use Original Equipment Manufacturer recommendation for this application.



Thank you,

Aaron N. Anderson

AMSOIL Technical Services

TZ250

That is a very interesting reply given this AMSOIL TSB specifically recommending 2 separate AMSOIL products:

http://www.oildepot.ca/interesting-a...y-engines.html

Note that the TSB was written 5/28/09, well into the '09 model year. '09 owners manuals make specific statements about the use of synthetics which the author chose to ignore. Whether you agree with them or not is a separate issue, it just points to the fact that statements of this sort should be consumed with a substantial quantity of salt.