Pennzoil HD40

I've been away from this for quite a while now (was a certified marine mechanic for OMC, Volvo, Mercruiser and BMW back in the 70's-80's). But it used to be that all of the marine companies specified straight weight oil in thier applications. They marine service to towing a 3,000 Lb trailer behind your car or pick-up continuously up a 15% grade with gas to the floor or close to it. Obviously, that's much harder on engines (and the oil) than automotive service.
The problem with multi weights was (speaking from 20 years ago) that they were based on the lower grade stock, with additives to reduce viscosity reduction with temperature. So you start with a 10W oil, and add stuff to make it look like a 40W oil when it's at high temp. Those additives used to be unreliable, and would break down under severe duty - leaving you with 10W oil in your expensive boat motor.

I stuck by that for years - only running 40W (Valvoline, for what it's worth) in my boats (my last one going over 1700 hours while I owned it - and still running to this day).

Recently, I've done more reading and got comfortable with the multiweight synthetics. In fact, I think Mercruiser even markets one. I now run a heavy duty 15W-40 synthetic in my GT-40 engine. Time will tell if that was a good decision....

Bottom line - I'd either stick with a straight weight, or a multiweight that was specifically designed for severe service. But that's my opinion....

john33617 wrote: Processed and burned for energy recovery, which involves removing water and particulates so that used oil can be burned as fuel to generate heat or to power industrial operations. This form of recycling is not as preferable as methods that reuse the material because it only enables the oil to be reused once. Nonetheless, valuable energy is provided (about the same as provided by normal heating oil).

That doesn't mean it's ok to spike your car's gas tank with used oil. They're talking about firing cement kilns, boiling water for electricity generation and large stationary equiptment or ships.

I wouldn't pour any used oil in a gasoline engine. Oil burns way too hot (too many BTUs). A Diesel Engine, maybe.

You're pouring old 10-30 oil into your gas tank? I've never heard of anything like that b4. This is just an early April Fools Day joke, right?

don't pour it in without some kind of filter , paper towel , rag or it could plug the fuel filter , and don't go over 30-40 percent , it will start smoking , the power gain is amazing.

I use walmart 10-30 was cheap , gone from 4.39 to 6.39 for 5 qts , rotella best dino oil , 7.50 gal , pour waste oil in my trucks fuel tank , the more oil I put in the better it runs , sometimes 2-3 gal per tank .

I've always liked Castrol 20W-50 year 'round in Central Texas.
As far as the parafin build up in the engine, I've heard it all my life but I don't beleive it. While it is true Pennsilvaina CRUDE leaves parafin as a final distillation product, it is also true Texas CRUDE leaves asphalt as a final distillation product. The motor oil fraction is heavier than gasoline or diesel but it still isn't the bottom of the barrel. After the motor oil comes off, there's still heavy oil, grease and waxes. Then you get to the real nasty stuff and finally the asphalt or parafin.
I don't doubt after years of use there will be some goo buildup but the goo is neither parafin nor asphalt. It's long chain hydrocarbons that would be there regardless which brand of oil you used. I suspect the weight oil used would make a difference on how much goo but it'd need to think about it more.
Plus, nowadays, there's no telling what the origin of the crude was for any of the brands of motor oil.
This is the first time I've heard the low ash argument for Valoline and I'll buy that. I'm sure they use an additive to help it burn cleanly (like an oxygenate).
I've also been thinking about HD or Diesel Engine Oils. But it might be overkill unless you don't change the oil regularly?

delo and rotella are both hd and come in 15w40 and are both hd. i use rotella in the 88. i would use castrol if those wernt avalaible my .02

Anybody have an opinion on the Diesel/Marine 15-40 that some manufacturers now require?

I have been a fan of Valvoline oils through the years myself. One of the most famous racing engine builders of all time, Smokey Yunick, was also a user of this oil. Smokey says that Valvoline is a "low ash" oil which means that as the oil burns (whatever amount that is, because all motors do burn some) Valvoline (compared to some oils) leaves very little ash deposits behind. That means your engine stays cleaner inside for a longer period of time. And I agree with the weight as stated above, 10W-40 is right for just about any climate. Unless you live in Arizona, Southern Texas or anywhere else where it gets over 100 degrees. Then I'd use 20W-50 or straight 40 weight. I also agree with the statement made about Pennzoil. I had a friend who had a Chevy Silverado with about 90K miles. He had been a religious P'oil user and had the truck since new. When I looked under the valve cover on this truck, it looked like the famous Quaker State horror story from the past. I'd stay clear of these 2 brands (Pennzoil and Quaker State). I also believe Castol and Kendall are excellent products.

I use 5w-30. Straight 40 is thick.

I know I am going to get slammed for this or at least start an oil war. But, my OPPINION on Pennzoil AND Quaker State is that the two brands have a high parafin concentration that can lead to gunk/crude build up in the engine IF the oil is not religiously changed before the additives are used up.

My favorite brand (non synthetic) of oil is Valvoline (Racing). My favorite synthetics are Amsoil and Red Line equally.

My theory on dino oil weights are:
1. Up to 50,000 miles (or equivalent hours) use 10w40 (southern climate point of view).
2. After 50,000 miles (or equivalent hours) 20w50.

I use 15w40 synthetic from second oil change onward. I avoid switching high mileage engines to synthetic due to potential seal leak problems and unknown engine cleanliness.

With all that said, to each his own and I am not interested in a oil war as this is only MY oppinion.