Custom mix 5w25 - good or bad?

[bob_ninja]

Originally Posted By: Al
I think with the price of gas what it is and the cost of your relatively new vehicle..seems lame to look at saving a couple bucks. Go with the 0w30 and run it out longer.

The 2.5 NA's are super easy on oil. You can easily run 10,000 miles on it.


Many manuals here in Canada call for Severe Service (certainly during winter) which is usually about half OCI. It has to do with tough weather conditions, moisture, salt, etc.

Also keep in mind that our car bodies tend to degrade much sooner than engines. So if additional wear from 5W20 reduces engine life from say 500K to 400K then it doesn't matter as body may fall apart at 200K (just making up numbers)

I am just getting to 100K on my oldest 13 year old car. Rust is still not too bad but I cannot see how I can go past 200K at most.

 

[scoobie]

Quaker State conventional 5w20 is fairly average for viscosity. And the 5w30 Quaker State Synthetic is viscous when hot, at cSt 11.3, but still has excellent cold properties (better than the 5w20 conventional)
As far as rusting out goes, (the scoobie is driven by my wife) I drive a 13 year old Dodge Colt (Mitsubishi) with 203,000 on the clock. It is exposed every year to heavy road salt applications. The car has been oil sprayed annually AND DOES NOT HAVE A SINGLE SPOT OF RUST - it is as immaculate as the day it came off the assembly line. The floor pan is perfect, and the original factory black stuff that was put on is still there, and the annual oil spray keeps it soft and tacky. I now purchase FLUID FILM wool wax anti rust compound by the 5 Gallon pail, and I have my mechanic mix it 50:50 with Safety Kleen
anti rust oil, and spray it on. One car uses 3 quarts of liquid spray each year, with no overspray, and no drip. The Fluid Film is caller AR, and it is like a grease, but when you stir it, mix it with oil, and heat it up, it goes on beautifully with a paint sprayer. The US military uses Fluid Film on all of their nuclear submarines, and even on the space shuttle. I had the car repainted at 10 years, even though the paint was still perfect, just to add an extra touch of protection. This is instead of waxing. I'm too lazy to wax, and I never wash it.

So, after reading all of the expert opinions, keeping in mind I'm in Canada, and synthetic oil is expensive here, I will try to mix the Quaker State Synthetic 5w30 50:50 with Quaker State conventional 5w20, and possible put in a little shot of Promoly - Bob seems to think MoS2 is alright, so I'll put in only 1/4 of a bottle, do 2 winter spring oil changes, and one summer fall oil change, about 8000 miles for the summer fall, and in the winter, probably 2000 miles each change.

By doing this, and using FLUID FILM AR annually, and with close attention to the paint, this will be the last Impreza I'll ever have to buy. I will also continue to maintain the Colt, and repaint the entire car every 5 years. In about 25 years, I will order a remanufactured NA 2.5 flat four from Colorado.

 

[scoobie]

I've just been at the synlube site, and the hot viscosity of 30w oil is defined as cSt 9.3 - 12.5 Based on this, since my mix should be around
9.4, this would still qualify as a thin 30w, and so this should
still be appropriate, expecially since I am running at an ambient
of 0 F - 20 F, approximately. Synlube says that the most appropriate weight for an automobile engine in moderate ambient temperatures is 30W. At ambient 100 degrees F, you MUST use a 40W. It never gets that hot here, at most 80 - 90 degrees in a heat wave. According to the synlube site, if engine speed is INCREASED, such a long distance high speed driving, in LOW ambient temperatures, oil viscosity could be DECREASED (20W), and since my mix is almost a very thick 20W, I will be doing
very well even if I need to travel. and with DECREASED load, viscosity can be decreased, and usually my Impreza has a very light load ... the 2.5 NA flat four barely breaks into a sweat, it never tows, and the car has very low rolling resistance, and extremely low wind resistance, due to aerodynamics, I think this is the best oil for it. It's still about 2 months away before I will be changing the oil - I plan on doing it around Christmas.

 

[Rolf]

Originally Posted By: chevrofreak
You would be better off just using a straight 5W-20 synthetic


Redline 5W-20 has a nice load of moly and high ZDDP.

 

[flatlandtacoma]

Originally Posted By: scoobie
I had the car repainted at 10 years, even though the paint was still perfect


Originally Posted By: scoobie
synlube