About synthetic motor oils...

[Solid Snake]

I've noticed that the cold PA winter has several effects on my car. Whenever I'd start the car, I'd hear lifters tapping loudly. The little 2.2L 4 banger sounded like a diesel during warmup. Also, it was obvious that friction within the engine was quite high, whenever I'd give the gas a quick punch and let go in neutral, the RPMs would drop very quickly. One day when it was very cold, the engine screamed for two minutes straight. The oil isn't low, all four quarts are there, it's Quaker State 5W30. I even added something that's supposed to quiet valves and help protect the engine. My car has about 65K miles on it and I've been considering switching to synthetic. Lots of people tell me that switching to synthetic may cause leaks in my engine due to the fact that conventional oil leaves behind deposits in seals and gaskets. Independent lab tests make Amsoil look VERY good compared to anything else out there. The combination of Amsoil's oil and their filter is supposed to last 7500 miles and keep my engine happy and well protected through all conditions. What do you guys think?

[usslindstrom]

The guys at Crower, (They make camshafts), recommend not using synthetic oil.

Aparently, it gives your car a little more horsepower (Like 1 or 2), but they say it doesn`t outweigh the costs of the damage it will do to the engine. They say the best is still the al-natural way, and not fabricated.

I think they were recommending 20w50 for racing applications. You might want to check it out when you get a chance...

http://www.crower.com

"Use of Synthetic Oils
Crower does not recommend the use of synthetic motor oils in any racing applications, particularly hydraulic and flat tappet camshafts. The minimum gains in horsepower are offset by the excessive wear to cam and lifter surfaces. Crower recommends Kendall GT-1 (20W50) Petroleum based motor oil in all high performance applications. If your manual suggests running synthetic oil, then do so. We have found, however, that the benefits do not outweigh the costs. For additional information click here!" - Quote from their web-site.

[Solid Snake]

I'm just wondering how synthetic would damage a camshaft. If weight it the issue, you can buy synthetics in different weights.

From the same site:

The synthetics offer the only truly significant differences, due to their superior high temperature oxidation resistance, high film strength, very low tendency to form deposits, stable viscosity base, and low temperature flow characteristics. Synthetics are superior lubricants compared to traditional petroleum oils. You will have to decide if their high cost is justified in your application.

I'd like to hear about why they're not recommended.

[whitebeard21]

I used synthetic in 14 service trucks. The average rebuild on an engine was 500,000 miles. You will find the engine starts easier in 0 degree weather. Crower has a sponsorship deal with the oil co. I recommend Mobil 1. Change your filter after 500 miles because it will cut a ton of crud out of your engine.
I know a man that knocked a hole in his oilpan and drove 5 miles. When we dropped the caps and checked the bearings there was minimal wear. I do not recommend doing that, if just blew my mind when I saw it.

[Gomer]

DO NOT PUT 20W50 IN A COLD CLIMATE CAR. That stuff is about 3 times thicker than 5W30 at 100F, and even worse as it gets colder. You can't even poor 20W50 at 11 below. 5W30 will pour all the way down to 45 below. 5W30 is the standard for me here in the winter.

You car's oil pump can't pump honey.

As for the problems w/ synthetic oils in old milage cars. The molecules in synthetic oil are very uniform in size and shape. The molecules in natural oil are comparatively irregular. This means that any gap in your engine small enough to allow one synthetic molecule through, will allow all of them through. With a natural oil, the large, irregular molecule will bridge the gap and maintain a seal.

You won't typically see an all out hemorage in older mileage vehicles, but the odds of gaskets and seals seeping/weeping oil become great when you jump to synthetic in an old car.

FYI, 2+ years at a garage here and a year at autozone. Not the greatest credentials, but not talking out of my rear either.

[J-Excel]

A research scientist for Mobil that my friend knows helped develop Mobil 1. He changes his oil every 100,000 miles. No problems. My friend changes his once a year (~15,000 miles). He's got about 100,000 miles on his car. No problems. Synthetics don't break down hardly at all. My father-in-law switched to sythetic on a car with 150,000 miles and blew the engine within a week. Based on those three peoples stories I tend to agree with Gomer.

[MTAtech]

Gomer is absolutely right. When I bought my first car (1975) I changed my own oil and decided to learn everything about oil. Mobil 1 just came out and was $5 per qt then (1975 dollars). Consumer Reports rated it and determined that compared to using regular oils and changing at the manufacturer's recommended times they saw no differences. Their judgment was that it did not pay.

In the oil spec., (#W-##), the number before the 'W' refers to cold weather viscosity. (The lower number, the more cold protection). The '-##' refers to high temperature protection. (The higher the number the better.) Thus a 5W-50 would protect the car year round. Unfortunately, they don't make a 5W-50.

You should use a 5W-30 in cold weather areas in the winter and 20W-50 in hot temperature areas in the summer.

To get extra protection, I used to buy at a speed shop a substance called molybdenum disulfide that I added to the oil. It turns the oil jet black and fooled people into thinking the oil was dirty but it gave extra protection against wear. I used the molybdenum on my 2nd car, a 1979 Mazda 626. At 150,000 I got rid of it when just about everything but the engine at trans was falling apart. The engine sounded like new.

[DaveLewis]

New high performance cars like Corvettes come from the factory with synthetic oil. I've run Mobil 1 in my last two vehicles with no problems at all. I work at a tech school and all of the automotive instructors swear by the synthetics. I've seen a small improvement (maybe 1 mpg) in gas mileage. I change filters at about 5,000 miles and oil about every 10,000. I know that you can't go by this but when I do the oil it still "looks" clean and doesn't have the acid smell that you get with high mileage petroleum base oils. I use Mobil 1 filters - they're a couple of dollars more than the Wal Mart specials but they seem to work for me. I can't speak to switching over to synthetic oils in a very high mileage engine - but I will say that I blew up a 454 Chevy at 175K that had run on petroleum base oil from day one.

[thekingofpain]

I use Amsoil thruout---engine, tranny, rearend---got tired of dumping hardly used dino oil...

[MTAtech]

I found this EPA test of a molybdenum disulfide product (PetroMoly®.) The EPA said that the product improved fuel economy by 2-3%. http://www.epa.gov/otaq/consumer/devices/r99001.pdf