jim11787

General question- picked up my Jeep this month. How many miles are recommended before switching to synthetic? I used to think the engine had to be broken in before switching.

TMahaffey

If you read Amoils website, they say no break in oil or time period is needed. I think they are probably right, but wasnt sure so I waited 1,000 miles. I couldn't go longer because I was getting horrible cold start symptoms, and hearing my engine suffering in -10 degrees (f) was driving me iNSANE. (symptoms gone after the switch).

However, I did pit the engine through the paces for the first 1,000 miles. I varied throttle and RPM constantly and gave it a couple full throttle 0-60's daily. (nothing over 4500 RPM). And 1 or two full throttle to redline.

TMahaffey

Yes and Thank You. Let's set aside warranty issues and look at the big picture. I am not concerned with warranty as I am with longevity after 100,000 miles. I am doing this for the team. (However my opinion on warranty still stands, I am NOT voiding my warranty.). But, let me worry about it. Just take what I put here and put it in your knowledge bank. I will stay non-biased and strictly scientific. I will only post true results and facts, no opinions.

Remember, I am doing no harm to my engine, as I will be changing the oil WHEN THE OIL MINDER tells me too. I will ONLY go longer once the oil analysis people tell me my engine is handling the oil well, and the oil is still good. I will post all oil analysis results here for you to view and study.

I am doing this because no one else has (for JK Wranglers) and I want to be part of this group. Hell, forums like this and aftermarket knowledge, and parts, is the #1 reason I bought a wrangler. Now I'm giving back.

ClaytonT

I've been on the Amsoil 25,000mi or 1 year plan since March '07, about a week and 100 or so miles after I bought the Jeep new. Only time will tell. I changed the oil a little early this year (mid-Feb), because I'm driving more stop/start than I did in FL.

I never took any measurements, just bought into the Amsoil marketing. I got their monthly magazine the other day and the introduction letter by the founder talked quite a bit about the beginnings of synthetics for ordinary vehicles.

The part I found most interesting was about Amsoil and Mobil 1 offering products recommending 25,000mi oil changes in THE EARLY 1970's. The article claims Mobil 1 soon caved/re-positioned due to public fear and scoffing at longer oil change intervals and discontinued it's 25K line.

The article then talked about Mobil slowly re-introducing extended oil change intervals, and of course now marketing a 15,000 mile synthetic.

***I haven't verified any of this info, just thought the article was interesting, because I get the feeling that this synthetic stuff is pretty new, but not, just takes a while to catch on, I guess.***

To TMahaffey: Thanks for trying to document your experience! You apparently have the drive whereas I have only momentary thoughts.

rickyj

But why would you run Castrol for just 3k miles? It is a high quality synthetic. I run mine to 6k, if your manual says to 8k run it to that. So you are talking 2 oil changes. Castrol and Mobil-1 go on sale at Advance Auto with a filter at least every other month. Castrol was I think $34 with a Bosch filter. So total cost to 15k would be less than $70.

Notice that the examples Amsoil uses are things like car radio, seat belt, windshield wiper. There is no correlation between these items and the engine. That is what the MMA was meant to address. Issues where someone had installed an aftermarket stereo and the manufacture was trying to deny engine warranty because the car had been "modified". Extended drain intervals and engine failure are more likely to be related. I would have to imagine there is some sort of "reasonableness" standard in the MMA. If you never once change your oil, there is a certain outside possibility that an engine failure could have been caused by factory defects, and not the oil. But if every manufacturer had to "prove" that the oil, x, or y, was at the absolute root cause it would stop commerce as we know it.

But I will agree with Amsoil that running their product will not cause unrelated items to be questioned.

I believe you. Service intervals are continuing to increase. Odd though in that it is the same exact engine, at least as far as I know.

TMahaffey

Yes Castrol Syntec is a great oil. So is Mobil 1. I was speaking of regular dino Castrol. The best bet for everyone is to run oil until the oil life indicator says it's tune to change.

I'm not worried about warranty here. So don't worry about my engine. I am doing this for the thousands of people who are indeed doing the Amsoil's claimed 25,000 mile and 35,000 mile intervals. Even I, to some degree know that these intervals are far fetched for some vehicles. That's why I will be testing as I go, then will find a happy medium to stick with after I can verify it works, and that it's not "hype". The only way to know is to do oil analysis on your vehicle, with your oil type.

I invite anyone to do your own oil samples as well. You can pick up cheap ones for $15 at Napa. Test your mopar, valvoline, and Castrol at 3,000 miles if you want. Put the results here for us to see. Test your beloved Amsoil, Royal Purple, and Mobil 1 , and let's compare! I thought finding out the best oil for our JK's would be fun and beneficial for all of us! Am I right?

joe002

You know the oil indicator light in the Jeep goes on based on an algorithm, and is not based on a sensor that detects when your oil looks bad and needs changing, right?

TMahaffey

Yes I am aware it uses engine load, RPM, coolant temp, outside temp, throttle, and others to calculate life of oil. So if someone drives highway for hours a day, they might reach the 8,000 mike mark. Whereas someone driving 10 miles a day at full throttle would likely not reach 2000 miles before the indicator goes off.

If I thought it actually analyzed the oil, it wouldn't be likely I would be doing oil analysis.

tdoster

I have never run synthetic, except in one car in my life. I have never lost an engine or transmission. My 07 is a spare car that I have put 74k on and never had a problem other than the typical death wobble, steering clunk, and all shut off three times in it's life. I change at 4k. An oil change is less than the cost of a tank of gas and takes 20 min. Out of my day. I don't see the upside of synthetic except in the gears that don't get as frequent attention. I have always driven well over 100k. Cold start, count to 30 before putting it in gear, and no matter what oil, your engine will never fail on an oil problem. Unless you drive it like you stoled it, oil is not going to make that big of a deal. And the cheapest way I found to squeeze a bunch more mpg's out was slowing down.

The fact is an engine needs so much lubricant. It never really is the lubricant itself that gets bad, it is the dirt, dust and particles that get between it and the metal. You are far better changing filters more than oil, any anyone running over 5k on the same filter regardless of the oil is asking for trouble in my years of experienced opinion.

But I would bet the farm two things cause premature engine and bearing failure. People who have the car in gear as soon as the engine catches and anyone going past 5k, even once.

joe002

Just wondering because the light will turn on at the same time no matter what oil you are running. The way I drive (off-road and 65-70 on the freeway), mine usually comes on at 2,500 miles.