Motor oil - What viscosity do you use?

[serehill]

for me

20W 50 Synthetic

[Brizio]

Mobil 1 10-W30.

[mattparliament]

the manual that comes with the jeep says 5w 30 when cold, and 10w30 when hot so that's what I do...

[svining]

Great Googley Moogley!

Simply put...there's no or little zinc in new car conventional oils per EPA ...your old car needs the zinc it was designed for (extra lube). The diesel Oils still have some last I heard so thats why guys use those. I heard that Castrol off road bike oil has some zinc yet.

New Synthetic oils are superior to conventional oils and these days there is not that big a price differential..especially considering you leave them in much longer...I go one year or 10,000 miles. The added bonus is that they are also highly detergent.

I went to great lengths to see that my motor is tight and my pump is fresh so I have great pressure. The new cars want 5-20w (ford), it gets into every little nook and cranny. So if your motor is not tight it will be a little leakier especially with the detergent.

I've heard people swear that synthetic oils will arrest almost all wear on moving parts, thin oils increase milage, get to where they need to be fast on start-up. So in my mind I have frozen my 360's wear at 140,000 miles. I will probably do a few short milage oil changes if it looks like the detergent is deslugging the motor in a big way. Just my way of thinking...there is a good website from engineers about oil research. Presently running mobil 1 ...(5-30)...75psi cold 60psi warm running and 40 psi at idle with a rebuilt pump last week before 20psi less across the board.

Never ending discussion on oil, I LOVE IT! Its always good to hear what you can about oil.

In my 911 I use 10 quarts of royal purple 20w50 synthetic. I truly believe in synthetic. I am also a pilot and I trust synthetic in aircraft thus my life.

When it come to weight it just depends on so many other things such as,
mileage on engine
Heat/average temperature in your area
Average trip length
Frequency your willing to change oil.

Personally my rebuilt engine required straight 20 weight break in oil then 20w50. The engine builder recomended this.

Personally, in Texas, i think 20w50 syn or dino is prolly the best to use. I also think if money is no object I would also use an oil cooler.

additives are great, I have not heard of adding zinc. I certainly cant hurt, but as with any oil arguements the end result is in time and mileage. I am not certain this board or users have been able to rack up enough miles with a certain brand of oil to actually see or make a call on whats best.

I have seen where the old oil additive, ash, has clogged up oil passages.

[Jeepguyp]

zinc

thats right. NO MORE ZINC in Rotella or other diesel oils. Mopar reformulated...cats on Cummins now. so I use synthetic Rot. in my Cummins....and either that or Mobil 15-50 syn. in my AMC engines. I think the syn. benefits make up for lack o zinc, so I dont slowly eat the camshaft. I have a guy here who sells "muscle car oil"...for older flat tappets like our V8s. conventional.oil...with zync already there. My Dad was getting it for the Avanti, but I talked him into Synthetics

[Randyre]

STP for small engines, in the Red bottle has ZDDP in it still. Also O'Riellies oil addative still has ZDDP. Or you can go for $7 qt Bradd Penn which is still at around 1400PPM ZDDP

[rreed]

So, if we're supposed to have ZDDP in our old AMCs, what are we supposed to do? Or is it zinc we're supposed to have? Where do we get it? And why is it important?

[svining]

Just compromise..Do it my Way!!

ZDDP, Zinc, Leaded Gas, Ash, are all extra lubricant additives in fuel and Oil. Synthetics are slipperier, stick to parts better (sheeting) etc. Forget the old Conventional Oils, they wouldn't have needed those additives if they lubricated all that well.

Mercedes Recommends mobil 1 at 10,000 mile increments. As far as what the shop manual recommends....my shop manual is 30 years old and Synthetic Oil wasn't around then. Like someone said...its backward compatible and exceeds original specs. Try buying Dexron that my manual recommends...its Dexron/mercron lll/lV now and exceeds those old specs, and is backward compatible.

My waggie is worth more then a Mercedes...just ask Marneus. lol and it gets Mobil 1....could I get paid for this ad?

So, if we're supposed to have ZDDP in our old AMCs, what are we supposed to do? Or is it zinc we're supposed to have? Where do we get it? And why is it important?

[cccamoj10]

rebuilt 258

I have just installed a rebuilt barn find motor, it took some time getting all those Mud-dobbers out of every open bolt hole & tube, It was rebuilt about 10 years ago and was set aside for a 360 swap. There was about a cup of water (condensate) in oil pan and a few tablespoons in each piston, but a good prelube saved the walls. I no longer have to worry about touching the back of the truck, or wiping the "Mosquito ControL" tags off tailgate.
I'm going synthetic after break-in and was wondering about the 'Oil Filter Magnets' I have seen advertised. and what about the PTFE Teflon Holy Grail of additives. are they DOA?

[drcom]

90 weight gear oil

I use straight 90 weight gear oil so it will stop leaking !!!!!

[Jeepguyp]

STP

I couldnt get my Dad to stop putting blue-bottle STP in our old 77 Olds(R.I.P. , now in China in a smelt).... but STP has paraffin(wax)... accumulative

[rreed]

I've seen what happens when paraffin builds up in engines. NOT pretty, and engine rebuilders throw a screaming fit when they find it. Didn't know STP engine treatment had it in it.

I'm not driving a Mercedes, I'm driving a '76 360 and '81 258 (not at the same time, of course) both AMC. I would like to make sure I'm running the proper oil to help them live a long and healthy life. The 360 leaks too much to pour out expensive synthetic on the ground. The 258 will get freshened up w/ all new seals and gaskets but just because it's "synthetic" does it mean it will have everything the engine needs?

Last I recall was that Dupont threw a screaming fit over people putting Teflon in their motors via those oil filters that came out w/ it in there about 15 or so years back. They said something about "do not put Teflon in an internal combustion engine, it does not belong there." I try to be wary of snake oil, myself.

I'm also curious about the oil filter magnets, though for the price tag I'll just bust up an old speaker magnet and stick the chunks to the side of the oil filter one of these days. Figure surely it couldn't hurt...

[95steel]

I've seen what happens when paraffin builds up in engines. NOT pretty, and engine rebuilders throw a screaming fit when they find it. Didn't know STP engine treatment had it in it.

I'm not driving a Mercedes, I'm driving a '76 360 and '81 258 (not at the same time, of course) both AMC. I would like to make sure I'm running the proper oil to help them live a long and healthy life. The 360 leaks too much to pour out expensive synthetic on the ground. The 258 will get freshened up w/ all new seals and gaskets but just because it's "synthetic" does it mean it will have everything the engine needs?

Last I recall was that Dupont threw a screaming fit over people putting Teflon in their motors via those oil filters that came out w/ it in there about 15 or so years back. They said something about "do not put Teflon in an internal combustion engine, it does not belong there." I try to be wary of snake oil, myself.

I'm also curious about the oil filter magnets, though for the price tag I'll just bust up an old speaker magnet and stick the chunks to the side of the oil filter one of these days. Figure surely it couldn't hurt...

Rick,

Your in Tejas now, run rotella and you and your engine will be happy. If it gets cold long enough (Dec-Feb/March) run rotella synth 5w40 for colder months.

Most oils are a parifin based oil, people blamed crapy pvc designs and bad maintenance on oil. Yes some oils are better than others, not going to start that arguement... Our engines will require oil changes more often if used for short trips because the engine won't be able to get warm enough to boil out condensation (what causes most sludge build ups). I am not a big believer in oil additives, I'd rather buy better oil.

Adam

[codyyy]

I haven't ran my old engine long enough to know the effects of what oil to use, but I put in 10-30 as that is basically what it says to use in the Haynes manual I have. I might decide to put STP or Lucas Oil Break-In for the zinc content but I'll hold off for now, I'm keeping it simple.

[Herk]

Rotella T6 5w40 synthetic in EVERYTHING.

I don't worry too much about oil pressure, I have the relief valve set at only 45 PSI on my Gladiator. I am more concerned about how fast I get pressure (circulation) on cold starts, how soon it drops to the regulated pressure when warm, and how well it maintains regulated pressure.

Viscosity is RESISTANCE TO FLOW, more is not better. Also since the oil pressure tap on our engines is typically upstream of any bearings, that high pressure may be indicating that oil isn't getting to where it's needed.