this could be a never ending debate with google returning 100's of opinions. The only number that is not opinion is that of the factory. What I've gathered over the years is what's important inside the engine (it gets over 95F here in Phila too).

copy and paste

https://www.bobistheoilguy.com/forum...Number=2946702

https: //www.bobistheoilguy.com/forums/ubbthreads.php?ubb=showflat&Number=2946702

 

It's not necessarily the extreme heat here but the lack of cold temps. Multi weight oils are only useful during cold start conditions. Again this is only for the person asking the recent question who lives in Az. We could theoretically use straight 30 weight oil but I never would. We almost never see temps in the 30's. When it does happen it's at 5am and only lasts for an hour or so. Most people don't get up and start the car until 7 or 8am and by then the sun is up and we are back in the 40's. It's also not uncommon for us to see 100 days straight over 100 degrees in the summer months! There are hundreds of oil viscosity temp charts out there and if you look closely us Arizonians fall in a 10w30 or 10w40 range...

 

conventional? no way, dudes straight up lying or ignorant, most likely wants you to buy THEIR product as they get more money that way...his claim is pretty easy to prove false too given all the research, both from actual scientists and also oil analysis' from general public, that synthetic is superior by far.

I use castrol synthetic, toyota switched to conventional castrol after their sludge motor campaign a decade or two ago (they were using penzoil, I wouldn't use that stuff in my lawn mower), but synthetic is far superior in regards to protection and longevity, ANY synthetic is better than conventional oil by far. I prefer mobile 1 or castrol, and don't use frame filters...they are made of carboard...literally...maybe not their more expensive ones but still.

My next fluid changes I will be switching to all amsoil products, there's quite a bit of data out there showing amsoil is even better than normal synthetics, even better than the other high end synthetics like rp. No I don't work for amsoil or even own stock, just stating what I found when I looked into various oils; conventional, synthetic, high end synthetics. I doubt I NEED the higher end synthetics but why not?

 

The service manager is right, as Toyota Motor Corp. wrote a PhD like publication stating there is absolutely positively no benefit to using synthetic motor oil through 500k of engine service. What has changed is to ignore marginal benefit > marginal cost and to increase the fleet mpgs due to CAFE.

BMW splits hairs where a 320i gets one cheaper synth, a 330/340 gets a mid synth, and a M car gets the best synth. When people are in business they don't give things away.

Back then, the internet was loosey goosey and you could find all kinds of information online like that. I wish I had saved it as a pdf.

At the same time, if I can get a 5 qt. jug of synthetic for $25, with a $10 rebate, net cost $3/qt., I'm simply willing to pay for synthetic. But does the car need it? No it does not. It didn't even come from the factory with it.

 

synthetic protects better, that's very well established, there are also numerous blackstone lab reports by engine builders showing this. It also goes longer between oil changes, this is also well established via various studies and blackstone lab reports.

can you get buy on conventional, sure, never said you couldn't...but synthetic IS better. For my money I go with the better option. Who cares what it came with from the factory? There are better transmission fluids too. Older cars didn't come with the latest conventional oils or transmission fluids either but it's always best to use better fluids.

You can debate brands but you can't debate the superior quality of synthetic over conventional

I don't NEED a lexus, my old 93 accord worked just fine...but the ls430 is better.

 

Conventional motor oil is approximately $5 cheaper per 5 qt jug. For you and me, if we decided to eat lunch out, instead of in the office, that could be $20 right there. But if we operated a fleet of 7,000 vehicles, suddenly $5/$23=21.7% makes a huge difference. I talked to a buddy who is a fleet manager their tractors are about $130k brand new and take 45 quarts of motor oil. They change it every 60,000 miles. I said 60k? He said yeah that is the upper limit of the interval. They are not going to do it at 57k, 55k, 52k, 25k because it's better, etc. They own these vehicles and are running a business with tight margins. The question was whether or not the service manager was wrong. No, he was not. Using synthetic is a waste of money, about $5 per change. But you and I can afford it.

 

Synthetic for extended drain intervals may be a good idea but for 5k oil changes I'd use any 5w-30 on sale. We're lucky to have cars that aren't too finicky about oil.

 

Can anyone report issues with keeping synthetic in our old cars? I think I will stick with conventional oil, as that is what the car has had since new. I hate oil leaks. Probably not a real concern tho.

 

I used synthetic 5W-30 in my last oil change, at 114,000 miles, and I believe this was the first time in the vehicle's history that synthetic was ever used. Still have no oil leaks and the valve cover gaskets are bone dry. Oil change was about 6 months ago.

 

I've always been a Mobil 1 guy, and have run it in my V8 4runner since new. Pretty darn close engine wise. I have 2K miles or so to decide.

 

 

again I thought the notion of leaks after switching to synth was applicable to 80's and very early 90's cars....the seals wanted the mineral spirits in the dino juice, but generally doesn't apply to any car mid 90's on....

 

I wouldn't think of putting anything other than synthetic in my car. Have been using synthetic in all my cars since 1991.

 

Another vote for 5W30 Mobil 1 synthetic (or any synthetic). I have been using Mobil 1 because they have rebates in the last few years and the price is not much different than regular oil which I am sure it will work fine too. I just like using synthetic oil because I can extend oil change.

 

Valvoline MaxLife 5W-30 here, and doing changes every 5,000km (3,100 miles). 275,000km and the car runs as smooth and buttery as my 13,000 mile Aston.