FredSM

Finally took Rick's (Synergy) advice and swapped out my 5W30 for 10W and put in the 160 TStat. Also added some WaterWetter and dropped the coolant mix to a little less than 50/50 (in favor of water). Although it was ~5-10 degrees cooler this AM than past months, I saw nothing over 170 degrees on the coolant (had been ~200 no matter what the ambient) and nothing over 198 oil temp. Oil temps had me bothered for some time . . . I've been seeing in the mid 220s even in cooler air, and high 230s into the 240s in an afternoon commute on a 90 degree day. Comparisons are all highway, overdrive cruising after ~40 mi. So, which change made the diff? Or is it mother nature? I was too impatient to try one thing at a time, sorry. I'm curious how this will change with an afternoon commute.

FM

dennis50nj

the 160 stat

edv2122

not08crmanymore

and isn't changing the oil's weight a little dangerous to the motor?

JFTaylor

That 10W will kill your motor

WoodChuck2

Are you nuts, 10w oil!!

calemasters

You may want the engine oil temp to get over 212 degrees F, to boil off any water that occurs from the combustion of the hydocarbon fuel. Water in the crankcase will do you no good.

The powertrain guys spec'ed a 195 degree F thermostat for a reason.

VET4LES

EuroRod

What little condensation inside the engine will evaporate anytime the oil temp exceeds the ambient temp. The hotter the oil, the faster it will evaporate. Period. 10W40 synthetic (Mobil, Royal P., whatever) will not hurt engine. Mobil 1 is actually a relatively poor performing lubricant, compared to whats avilable today. Follow the money, and you'll discover why GM recommends it in the Vette. Mobie pays GM to put it in there, figuring they'll sell more from the Lemmings Effect! GM recommends 5W30 for fuel efficiency and emissions. 10w40 will protect the moving parts better. In hot weather, I use 20W50.

LMBC6Brian

No, you are very incorrect and putting a ton more drag on your engine. The 10w oil just means that its heaver when its cold in the morning causing it to be more like molassis in your oil pan. The 5 weight oil is much better for cold starts and then when it warms up you want it to be 30 weight. 40 and 50 are too heavy. Its like trying to run under water, vs trying to run under mud. Get that heavy crap out of there and follow what GM has proved works best for YEARS>!! I use 10w40 in my motorcycle, but it revs to 13,000rpm.

calemasters

Wrong. At 1 atmosphere, water gasses at 100 degrees C (212 degrees F).

rustyguns

at standard pressure

Wayne O

With my engine I'll run 15W50 Mobil 1 only when running on a road course (and it's hot here in Arizona to begin with). I change back to 5W30 for 'normal' driving.

I know Water Wetter is sometimes used by guys running on the track especially if their car has any risk of over-heating. They'd rather have Water Wetter on the track than anti-freeze....regular coolant on the asphalt is virtually invisible and slicker than oil...definitely dangerous.

Perhaps GM does recommend Mobil 1 for monetary consideration. Irregardless, many professional racing teams (whether they're sponsored by Mobil 1 or not) actually use the product with seemingly good results.

rustyguns

where you guys been? most of the race teams are usin 0-5w oil !

most new cars require 0-20w or your warranty is void!

world isa changin' !

ZO6 Fan

Can somebody please explain to me the differences in the weight designations? I.E. 5W-30 Etc Thanks

oneblackvette

5w oil good 10w who knows.....

But oil temps do need to get up enough to do there job.

FredSM

Thanks for the comments. I moved to 10W because my tuner recommended it for all my vehicles in this area. From what I read on the subject (admittedly all from the World Wide Sewer . . . er, Web), the viscosity index is increased mainly through the use of additives, including polymers. The greater the diff between cold and warm #'s, the more additives. Those additives apparently tend to break down more severely than the oil itself under mechanical shear stresses, and can form some nasty residues. Apparently, the narrower the range you can tolerate, the less additives you'll need, regardless of the running temp viscosity you're trying to achieve. Of course, I'm an EE trying to be a chemist, so who knows. But given where I live, my car is not likely to ever see startup temps below 50F. So, I'm betting I can tolerate a higher "winter" viscosity.

As for the TSTat . . . I've read with interest and amusement the TStat war threads. I know next to nothing myself on the subject, and certainly agree that GM knows what it is doing. But I'm equally sure when you build 40K+ of something this complex and expensive that you'll have to warrant for some time, you do so conservatively with a lean towards the more extreme environmental conditions. My only real defense, again, is my tuner recommended it.

BTW, on my sprint home yesterday (ambient ranged from mid 70's to mid 80's) I never saw oil temps above the low 220s and coolant never got above 200 . . . does appear much less stable as I was seeing it bounce between 170 and mid 190s under what I thought was basically the same conditions.

FM

DiverDown

So are you saying if you leave a glass of water on your kitchen sink it will never evaporate?

The water in the oil will evaporate from the oil but not as quickly.

calemasters

The API/SAE designation for multi-grade oils includes two grade numbers; for example, 5W-30 designates a common multi-grade oil. The first number associated with the W (winter) is not rated at any single temperature. The "10W" means that this oil can be pumped by your engine as well as a single-grade SAE 10 oil can be pumped. "5W" can be pumped at a lower temperature than "10W". "0W" can be pumped at a lower temperature than "5W", and thins less at temperatures above 99°C (210°F). The second number, 30, means that the viscosity of this multi-grade oil at 100°C (212°F) operating temperature corresponds to the viscosity of a single-grade 30 oil at same temperature. The governing SAE standard is called SAE J300. The motor oil grade and viscosity to be used in a given vehicle is specified by the manufacturer of the vehicle.

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