Synthetic motor oil & additives? (1 Viewer)

[Ryan Wright]

Hello all,
As some of you know, I bought this new Fiero with the supercharged 3.8l V6. The guy I bought it from says he only uses Mobil 1 along with a bottle of Prolong engine treatment every 5000 miles and highly recommends I do the same. I thought, sure, might as well keep putting the same thing he's been putting in it. I'm almost up for an oil change so I went to the store today to buy my oil.
Well, Mobil 1 is a synthetic at $5 a quart. A bottle of Prolong (does 1 oil change) is $20. A better oil filter to handle the synthetic stuff is $10. So I'm looking at about $60 for a single oil change. Granted, I should be able to go 5000-7000 miles on one change, but something about it just bothers me.
So, I thought I'd post here to get your thoughts on synthetic oil and this Prolong treatment. Is it all a bunch of snake oil? Does it REALLY make a difference whether I use this every 7k miles or use regular oil every 3k? The guy I bought the car from seemed to know what he was talking about, but on the other hand, perhaps he was just sucked into their marketing ploy. I don't mind shelling out the cash for the "good stuff" if it's really that great but don't want to waste my money if it's not necessary.
What do you think?
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-Ryan (http://www.ryanwright.com )
Before you criticize someone, walk a mile in their shoes.
That way, when you do criticize them, you'll be a mile away and you'll have their shoes.

 

[Erich_H]

Stick with the Mobil 1, but ditch that snake oil. The Prolong is probably doing more harm than good. Just in case your are wondering, my main hobby is my car, so I have some experience in this area. I also spend more time on car forums, and nobody, and I mean NOBODY uses that stuff.

 

[Steve Owen]

I agree 100% with Erich. There's enough scientific evidence out there to prove that synthetic oil is better than conventional in a lot of reasons. I use Mobil 1 in my car. It costs more, but I can feel comforable going 5K miles w/o changing oil.
The other additives are junk and should be avoided .
-Steve

 

[Kolya]

I've always run straight synthetic (Castrol Syntec) in my Acuras ('90 & '98 Integra) and I've had 250000 trouble free miles (and my engine spends a LOT of time above 7000 RPM
I agree with the other posters, ditch the Prolong.

 

[Todd Hochard]

I agree with everyone else. Synthetics are the real deal. The engine will last much longer with the "fake" stuff. It flows better, doesn't break down over time, and is much more tolerant of high temperatures. Synthetics will protect the engine better if you like to "stand on it". You don't need to use a $10 oil filter (I assume you speak of the Mobil 1 filter), though- use the same one you've always trusted.
I'm a little leary of going to the extended change intervals with synthetics, though. Even though they are better lubricants, you still get condensation and fuel contamination of the oil- things that the filter cannot remove. Now, most modern engines have rapid heatup, and exceedingly tight tolerances, so these effects are minimized somewhat, but they are still there. My personal change interval is 5000 miles. I do this with the intent of getting at least 250,000 miles, without ever doing any corrective work on the internals. It has worked on one car- the rest I didn't keep long enough.

I have two cars that will be staying at least that long now, though- A '95 Accord with 107K trouble-free miles so far, and a new '02 Acura TL-S, with only 5000. Both will be with me for the next ten years (it's a personal financial goal thing).
The additive, though, has to go. Virtually all modern oils, synthetic and dino juice, have a well prepared additives package. It is a well-researched, well-balanced mix. Adding extra stuff in the motor can upset this balance, and actually cause the additives to begin destroying one another. Specifically, things like Prolong, X-1, etc. usually contain high amounts of zinc, an anti-wear additive, which will actually destroy some of the anti-corrosion additives. Think of it like a cake made from scratch- all the ingredients must be measured, otherwise it tastes like crap.
I'd recommend the Mobil 1, 5W-30 for your climate, and change it every 6 months or 5000 miles, whichever comes first.
Todd

 

[Ryan Wright]

Thank you to all for the replies. The Prolong is history; I didn't buy it. I did purchase Mobile 1 10-30 with a regular old Fram filter and will change on a 5k mile schedule. Can someone explain to me the differences between, say, 5-30 and 10-30? I've always used 5-30 in all of my engines, though this car has had 10-30 in it. Is it better to stick with it, or should I change to 5-30? I haven't opened any of it yet so could trade it for 5-30 with no problems...
Thanks again!
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-Ryan (http://www.ryanwright.com )
Before you criticize someone, walk a mile in their shoes.
That way, when you do criticize them, you'll be a mile away and you'll have their shoes.

 

[Steve Russell]

10-30, or 5-30 refers to the oils viscosity or thickness at a certain temperature. The first number refers to its thickness cold( the lower the number the more free flowing the oil is in low temperatures). The second number(30, 40, 50 etc...) refers to viscosity at running temperature(again lower numbers means thinner oil) I would stick with 10-30 or 40 unless you live in a very cold area. I use valvoline 10-40 in my truck( I think the 40 weight gives a touch more oil pressure than 30). I use valvoline racing 20-50 in my 65 cutlass. The cutlass is summer driven only and I like to beat on it quite a bit(modified 403, 4-speed, 4.10 gears). The racing oil is actually recycled oil and all the paraffin has been removed so less chance for sludge or deposits.(Synthetic wouldn't do that either) Any way, didn't mean to start confusing you. Mobil 1 is good oil, 10-30 is probably fine. Good luck.

 

[Todd Hochard]

I suggested the 5W for below 40F startup conditions, because in newer engines with tighter tolerances, it can take a lot longer to get oil to the top of the engine on startup. And higher oil pressure isn't necessarily a good thing- oil pressure is measured at the outlet of the pump, so higher in this case simply means a larger pressure drop along the oil flow path.
Additionally, with stock oil pumps, particularly those found in GM engines of 80-up vintage, they can cavitate (lose suction pressure) at high RPM (above 5000). This, in turn, starves the bearings of oil pressure. BAD. I was actually able to see this happening in a friend's '96 Camaro at the track. Needless to say, he no longer subscribes to the thicker-is-better idea.
For GM V6s and V8s, higher mileage engines (>120K or so) probably should go to a 10W mix.
I've never used a 20W in any of my race engines (or a high pressure pump for that matter), as it robs too much HP from the engine, and has a greater tendency to "rope" around the crank at high RPM.
Todd
P.S. One engine that I'm particularly proud of- a 1978 two bolt 350, using only a cast crank, has made over 250 passes at the strip, shifting at 8500rpm. It hasn't come apart- yet!