I have heard about the Synthetic Oil anybody tell me is it good for $ runner/ thanks

You'll find people arguing both ways. Mostly the ones arguing against it are the people that stand to profit after your engine dies. If you have 110K+ miles on the engine, it might not be a good idea because the synthetic oil dissolves the sludge that might be plugging little leaks like by gaskets. Otherwise, I can say that I gained 2 mpg by switching to synthetic throughout, except the front diff because it doesn't get that much action. I run it on both my 4runners, an '85 with 175K and a '99 with 110K. I change it every 5K instead of 3K, due to the fact synthetic oil doesn't break down. Steve H

Thanks Steve, I have 103 k now on my truck let me know if ts good for this knd of mileage and how about the transmsson ol replace with synthetic transmission oil , thanks for ur help , Hasan Steve Hemphill

I think it just depends on how it was taken care of for the first 100K. If you park where you don't worry about leaks it's more than likely good to do. If it doesn't leak it was probably pretty well taken care of. Either way you'll be doing your engine (and transmission) a favor. Steve H

Well either oil is going to work. My parents use dyno oil and change it every 6k and there cars last over 100k. I doubt they would last to 200k, but they don't plan on keeping them. I perfer the synethic as it is suspossed to be better and since it can't hurt I might as well use it. The downside is that the price is 2-3 times as much as dyno oil. I do change it every 5k though and haven't had any issues in my 4runner. I actually switched it to synethic when I got it at 64k and I now have 81k on it. Ryan

Synthetic is good and bad. If you have an older engine Then I would say no. Synthetic has a tendency to open up leaks that were not noticeable in older engines or make existing one worse. If you have a newer engine or rebuilt then it is good. For diffs and trannys you should use the Toyota specified lubes as they are formulated specially for your car, unless someone can tell you specifically what brand and type is good for your truck. Sean Rauch 85 Supra 5M (7M soon) Cone Filter, Exhaust, Cold Air Scoop 86 4Runner Stock (for now that is) Winnipeg, Canada

It doesn't "make" it leak. It cleans up the inside of the engine so there's no sludge. THe way it was explained to me is like this. Dinosaur oil breaks down and makes sludge, which plugs up small leaks into gaskets that occur around inconsistencies in the mating surfaces, so the gaskets dry up. The synthetic oil, which would have swollen the gaskets and kept the leaks from going all the way through the mating surface, then runs right through the dried and cracked gasket. I don't know if that's what happened to me for sure, but twice I've bought used cars with a lot of miles, put synthetic oil in them and they started leaking. What do "modern" synthetic oils have in them to prevent that? Steve H

Steve- Sucks that you had a bad experience with high milage vehicles and synthetic oil. That's not been the case with me. I've started synth oil on vehicles with over 100k and have had no problems. I've always used Mobil 1. ~aaron

&gt; anyone tries synthetic oil <br>This is truly a question for ee_of_ee - at least to give a shove in the right direction:<br>"Can a Prius owner "safely" use 100% synthetic oil that meets, or exceeds ALL of the requirements as listed in the owner's manual?"<br>"Could the use of such oil void, or in ANY way, violate the terms of the warranty?"<br>Of course, I would supply the oil and cut a deal with the service department to use my oil.<br>If ee_of_ee or priusman can't offer an authorized, official statement, could one of you fine gentleman give me direction as to whom in Toyota can?<br>Thanks!<br>Bill Powell<br>(faster, faster - row! row!)

Warranty is administered by the sales organization, talk to pm. I'm leaving for Montreal tomorrow for EVS-17, so won't get to ask anyone about your questions until 10/26. Previous experience with other engines (aircraft, motorcycle, etc) suggests its prudent to use whatever the development people use.

You wrote... > Another way to increase MPG is to switch from 5W-30 to 5W-20... > thinner oil. Honda and Ford have made the switch. The oil weight on the new Hybird Civic is 0w-20. I saw this printed on the cap under the hood. peace, Linda