I'd be leary. Who said the mfg of Opti-4 will double the warranty, your dealer or the mfg of Opti-4 ? Also remeber a warranty is not a guarantee. Your dealer probably probably has a financial gain if you use it. (imo) - Kris

Link to product page included in lats post... also contained details on warranty.

It is a warranty through the mfg of the oil.

http://www.opti2-4.com/opti-4.htm

Cost of the stuff is 4 quarts for $40 I think.

Not sure if it is only for use in cold weather small engines like on a snow blower... as that is the application I have seen the dealer push it on.

Here is a link that might be useful: Opti

Opti-4 also comes in 10W-30 for cold weather use, and is excellent for any 4-cycle equipment. It's my 4-cycle oil of choice.

Here is a link that might be useful: Opti-2 link with Opti-4 info

If you NEVER changed oil, an engine most likely wouldn't have any problems lasting longer than twice the warranty period.
I used synthetic in my 18+ year old Honda once. I came to the conclusion that it gets dirty just as fast as dino. DIRT is the reason you change oil in a mower. I can change my dino about 3X as often for the same price as synthetic.
IF you use a decent oil and keep it changed frequently, the engine is going to outlast the rest of the mower.

I have absolutely nothing against synthetic. In some uses, it's outstanding! It's just that to me, it's really not MY best choice for an engine without an oil filter used in a "moderate" climate.
IF I had a snowblower that was used in sub 0 temps, I think syn would be great. Or maybe a lawnmower used where the temps were well over 100F. Personally, if it's really hot out, I mow early or late instead, when it's cooler:-)

Who brought up synthetic? I thought we were talking about Opti.

'If you NEVER changed oil, an engine most likely wouldn't have any problems lasting longer than twice the warranty period.'

I know a guy with a vintage Porsche who takes great care of it and used to be an SCCA racer. However, he will not change oil in his mower - kind of strange, don't you think?

'I used synthetic in my 18+ year old Honda once. I came to the conclusion that it gets dirty just as fast as dino.'

That would be right - shows the oil is working to clean the engine and keep particles in suspension.

'I can change my dino about 3X as often for the same price as synthetic'

Okay, but all the time you are using regular oil instead of synthetic, particularly in an air-cooled engine, you are getting none of the benefits of synthetic.

'IF you use a decent oil and keep it changed frequently, the engine is going to outlast the rest of the mower'

Nothing wrong with that, but 9 out of 10 don't change their oil frequently.

'IF I had a snowblower that was used in sub 0 temps, I think syn would be great. Or maybe a lawnmower used where the temps were well over 100F. Personally, if it's really hot out, I mow early or late instead, when it's cooler:-)'

This statement has to do with oil viscosity, not syn vs 'dino'.

To my knowledge... Opti-4 is a petroleum based lubricant... which means to me it is not a synthetic. More info on Mfg's website below.

Here is a link that might be useful: Opti-4

My mistake about it being synthetic. How much does it cost VS dino VS synthetic?

opti 4 is way over priced and its cheaper to by a synthetic if you can find it in an approiate weight .

No doubt it is priced high, but since you use 20 oz of it once a year, does it really matter? How about the Husqvarna synthetic for air-cooled engines that's $16/qt.? Find it on the Sten's site. I think there's a difference between regular automotive oil and oil designed for a small air-cooled engine, and I'm willing to pay more for it, particularly since I've had such good service from it.