David426

Just P urchase a 2002 z.. Looks like the owner had our local performance shop do regular Red Line Oil Changes... Good stuff.. It looks as though they used 20w50.. The owners manual does not recommend this viscosity.. 21st Century Muscle car has a great reputation.. Am I missing something here?

enigma94

I think thats way too thick. even with 5w30 here in hot AZ i only see oil temps top out at around 215-225. I'll be switching to a 10w40 when it gets warmer here but 20w50 is waaay too thick, it wont allow the oil to get to the optimal operating temp and could cause a loss of power and worse gas mileage, not to mention put more stress on the motor itself.

thetorch

Unless you have an engine that was intentionally built with large clearances, 20w-50 will only cause increased wear and HIGHER oil temperatures than a similar quality 5w-30 or 10w-30.

If your going to run Redline, I would recommend the 5w-30. If you want better protection for a much lower price, try Pennzoil Platinum 10w-30.

21STCENTURYMUSCLECAR

Hi David,

We carry Motul, Red Line & Mobil 1 in 30, 40 & 50 weights, I suggest
the heavier oils for road race cars where 270+ oil temps are not uncommon, we suggest 30w for most street cars unless you plan on tracking the car in the Texas Heat.

I have used 50w in my personal track car for the past 12+ years without a engine failure.

Best Regards,
John Page
Twenty First Century Muscle Cars

1%r

Just what John said.

I run a TT which tends to make the oil temps hotter. I tried RP 20/50 and the motor didn't like it at all, I went back to Mobil 1 15/50.

Unless your tracking the car or running a setup that are going to give you extreme oil temps listen to John.

Mr. Lucky

20w50 is too much for a stocker. Since you live in a mild climate, 10w30 is your best bet. I run Red Line 15w50 in my stroker though.

rustyguns

i run 15/50 mobil with track oil temps around 270+

if you run stock normally I bet you could run 0-20W and pick up one or two miles to the gallon!

thetorch

My empirical oil analysis data from the last 4 years of testing on my LS6 shows much higher wear and oil temperatures when using anything thicker than a 10w-30. I have not tried Redline 20w-50, but I have used Redline 10w-40 and it was a BIG step in the wrong direction. The poor wear and increased oil temperatures with 10w-40 told me that going thicker would make the situation worse.

My car is a daily driver and I participate in 3 - 4 HPDE's per year in the yellow run group. My testing spans both types of driving conditions and Dyson Analysis was the consulting engineer for all UOA's.

You can run a 40 or 50 weight oil in an LSx engine, but it is no where near the optimum weight to provide low wear, stability, and satisfactory oil temperatures. Redline 10w-30 and Pennzoil Platinum 10w-30 have both proven to easily withstand 285 - 290 oil temps during open track events with lower wear, greater stability, and identical oil change intervals.

Fastgenious

You are being stupid if you do not follow the rec of GM. If the car is stock I would stay with 5W30 or maybe even use 10W30... If you track it maybe a 40 weight syn.

rustyguns

As Forest Gump says..stupid is as stupid does

might try some 40w

David426

Thanks John.. The previous owner threw in a half quart of 20w50.. I've tried to contact him to see if thats what is in the crankcase.. From pulling out the dipstick (cold engine), it looks like the oil dripping off of the dipstick is much thinner.. The last receipt from 21st Century says Red Line oil service and does not specify the weight..