For a weekend and cruise-in car only, how often is it really necssary to hange the oil? Currently I do it twice a year. Once at end of year, and one about 2 months into the drive season.

Max miles a year is 2,000-2,500. Stored for 2-3 southern winters. I use Penzoil with Amsoil oil additive, but am now switching to Mobile One plus the Amsoil additive.

Bluesdog

You know how they say 3 months or 3000 miles? The 3 months part is because of acidic compounds that build up in the oil when the engine is short cycled. Bascially the blow-by that every engine has will create corrosive compounds in the oil. This is especially a problem if the oil doesn't get hot.

Now, as for your question - I don't have a straight answer. It depends on your driving habbits. Oil would last a year IMHO in the crank case of a motor that was never fired.

bluesdog, Ive never heard of an Amsoil additive for petro oil? Can you explain what it is?
I use Amsoil 10-w 40 and change is once a year, used only for cruises and shows. It sits from Nov. to April too.

Mine sees about 1000-1500 miles a year in our 6-month driving season; I change oil once a season, about ten miles before I park it in the garage for the winter (you want fresh oil in it while it's sitting all winter, not old oil full of condensate and acidic blow-by contaminants). I use plain ordinary brand-name 10W30 (Valvoline, Pennzoil, Castrol, etc.); they all have the same base stocks and additive packages to meet the API and OEM specs on the container.

There's no economic justification in my mind for expensive synthetics with that kind of duty cycle and oil change interval; regularly-driven high-mileage-accumulating cars and race cars are a different issue. I don't use any additives - they're already in the oil's additive package as it is, and don't deteriorate with the oil changed every 1500 miles. graemlins/thumbsup.gif

My wifes uncle has built engines for a living for about 40 years now. He built an engine for me once and told me he would warrany the motor for 30,000 only if I changed the oil and filter regularly and did not put penzoil in it. At one time (and I presume now), penzoil puts parafine in their oil. If you open a motor with 10,000 or so on penzoil, it will have a yellow film all over the internal parts.

I've heard that tale before, not sure if it's for real or an "urban legend"; Pennzoil meets the same API "SH" and OEM durability test specs as every other brand-name oil that carries the "SH" test approval, and I'm not aware of any owners' manuals that prohibit its use for warranty validation. graemlins/thumbsup.gif

Hmmm,.....I've been using Pennzoil in all the Nissans we've owned since '84, and have not seen a problem with them, one was a 85 300ZX with 152K.

And use Penn in everything else, GM truck incl., and they are all pretty clean inside, at least looking thru the oil fill opening into the rocker arm area. But, I do cahnge about 3000-3500 miles.

I've been using Penziol for about 25 years now & never have had a engine problem & some of my Cars & Trucks had between 150,000 & 200,000 miles on them & had never been torn down. I use Penziol 30 weight in my 396 & change it once after about 200 miles into the driving season & once right before I park it for the winter.

Pennzoil here for me too, in all my cars...never had a problem because of oil. My RX-7 had 208K on the clock before it gave out. 2 times a year or every 3000 mi on the 69...works for me! :D

I have researched this subject for over five years for differing articles that I have wrote online and in several magazines. I think you will find this interesting and maybe I can convert a few of youse out there.

I use REAL synthetics (from Group V and VI bases) from Mobile One/ Amsoil/REDLINE or Royal Purple ONLY.

All of these have superior lubricity indexes, film adheasion, viscosity indexes and moreover will not combine with blow-by products to produce acids in the crank case. Film adheasion is expotential compared to regular stuff ...something that creates a cushion when cold starting! On the synthetic thing...you either got to be all in or all out. Group III and Group IV based products are just over-refined regular oil such as the other "pretenders" such as Valvoline, Castrol, Penzoil yadda yadda yadda. Don't waste your money!

But, the real stuff is excellent. I can buy Mobile One jugs at WallMart for around $8 on sale. This is $2 a quart...well worth the extra $4 per change to have the best protection and less friction to boot. The wear protection will be a huge factor too. After tearing down engines with over 80K with synthetics you can detect wear at all if all is well.

So, in my book... synthetics all the way around and what's best you can easily push these super oils to 15 to 20K intervals in your regular cars and trucks which means the economics is actually reversed. Another myth busted!

One last interesting fact also. You will rethink your habbits! We all know that regular oils will combine with combustion by-products to form acids harmfull to steel and iron parts..right. Well, todays oils are manufactured with a slightly alkyline base right out of the can. This is in anticipation of acids to come! What happens is that "base" or alkylines attack aluminum, copper, and other "soft" metals. What happens is if you change your oil toooooo often (and you have fallen for the marketing of the...it needs to be changed every 3000 miles)you are damaging these parts as much as not changing enough. I have sent oil in for lab analysis and for regular oil and regular everyday starting and stopping the oil gets to the perfect acid/base solution at around 4 to 6000 miles! So you may be taking perfect oil out of your car to replace with a more harmful product. Even the manufacturers all recommend about 7000 miles between changes for this very reason! Not 3K as by the oil manufacturers. graemlins/clonk.gif

I report.....you decide!

Steve - are you saying Valvoline is false advertising when they say their "SynPower" oils are 100% synthetic? Same for Castrol "Syntec" they claim it's a "full synthetic" also...

Originally posted by HOTRODSRJ:

I use REAL synthetics (from Group V and VI bases) from Mobile One/ Amsoil/REDLINE or Royal Purple ONLY.
Aren't the PAO/esters Group IV & V, not V & VI with the cheaper synthetics like Castrol QS, Valvoline etc Group IIIs?

Click, my writing was faster than my thinking. I use Tufoil as the additive, not Amsoil. I was reading about Amsoil just before posting and got thoughts disqabobulated.

Thanks for everyone's response.

Bluesdog

Bowtie-70 you are correct. I didn't proof read my own post and got the "I" in the wrong place.

All "pretenders" such as Valvoline, Castrol, and etc are all Group III...which makes them simply highly refined regular stocks. Now, they are much better than just regular oils but do not share some of the features of the Group IV and V products such as Mobile One, Amsoil, RedLine, Royal Purple, and so forth.

A good site for definitions is http://www.performanceoiltechnology.com/baseoilcategories.htm

I found this board with alot of chemical experts and it features lab tests of used and new oils. Its a VERY cerebral site, lots of technical talk but for those interested in DEEP oil thinking its great to read.
All you want to read and learn about OIL (very technical, lab tests, engineers and chemists love it) (http://theoildrop.server101.com/cgi/ultimatebb.cgi)

I'm still confused, How can the ones I mentioned claim full synthetic or 100% synthetic if all they are is refined dino oil?

There are big differences in specifications in Europe vs US lubricants and mostly based on marketing BS here. Europe has it right for once on their spec for sythetic. The "fake" group III products cannot be called synthetic under Europe specs.

Here is some interesting history at http://www.oil4kids.com/syn-hist.htm

Also, the real story is put in perspective here. I have seen several redentions of this but it's factual and not marketing hype.

Go to http://www.oil-tech.com/dirty-secret.htm

Good bedtime reading. If you still want to change your oil every 3000 miles after reading these articles then I have a beautiful mountain lot in Florida I want to sell ya :D

Cool!! graemlins/thumbsup.gif

Steve, Thanks for the info...I owe you a beer, from all the $ I will be saving on less oil changes... graemlins/thumbsup.gif Mike smile.gif