Join Date: Oct 2008
Thanked 5 Times in 5 Posts
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Ever since the first internal combustion engine first sputtered to life over a century ago, 30 wt oil has been the ideal weight lubricant to use at normal operating temperatures... Nothing can change this fact. It's all metal sliding on metal and 30 wt is the best balance of lubrication and viscosity friction for most internal combustion engines.
Some racing applications use heavier grades to help protect engines with profoundly high mechanical pressures but these are exceptions to the rule.
Problemo is... 30 wt oil flows too slow when it's cold and any engine will be starved for oil for far too long every time it's fired up in cold weather.
Multi-grade oils solve this problem, but with a small price... The viscosity enhancers used to make multi-grade oils don't have much lubricating value themselves, so they reduce the lubricating potential of the oil a bit. 5W20 actually lubricates better than 5W30 because it contains more oil and less viscosity enhancers!
The problem with ultra light oils occurs when engines overheat... Ultralight oils get so thin when they are overheated they allow metal to metal contact, scoring bearings and permanently damaging the engine with remarkable swiftness. A heavier oil will tolerate overheating far better than a light oil will, and save your engine if you don't stop the car immediately once the temp gauge starts into the HOT zone.
The ultralight oil engines are designed for the 1 or 2 extra MPG they will get compared to a normal engine... Thinner oil means less viscosity friction and better mileage. The price we pay for this mileage is a much greater risk of blowing the engine the first time you drive it in an overheated state. The dealers and mechanics are in on the scam and your warranty will not cover an engine damaged in this way... You simply buy a new car. Good for the manufactures and the dealers, bad for you and me!
Unfortunately, the ultralight oil engines are DESIGNED for ultralight oil, and upping the viscosity much over the design specs can cause problems, not the least of which is the voiding of your warranty.
My solution to this problem is to run 5W20 synthetic the first 50K miles while the engine is new, tight, and under warranty, and the cooling system is not old enough to be having problems yet... Over 50K, I will be switching to 10W30 synthetic for the added protection it gives to older engines with cooling systems that may fail and cause an unexpected overheat which will destroy any engine running ultralight oil.
Any engine (especially a 4 banger) will loosen up quite a bit in 50K miles, and I'm banking the jump from 5W20 to 10W30 will not cause a problem. I also live in a part of the country that never sees sub-freezing temperatures, so the ultralight oil is less critical for my cold starts.