Sidney004

FWIW

Dave said the limiting factor is not the breakdown, degradation or loss of lubricity at elevated temperatures of the oil(we all knew that) but rather the degradation of the seals(elastomers) above 300F and degradation of the surface hardening treatments performed on camshafts, etc. above 320F. Also, for the engineering types out there, the viscosity at 300F for RL 10W40 is about 6.15 cSt, the RL 20W50 about 7.2 CSt

waddisme

That has always been my understanding - the oil can take that high of temps, but parts in the motor cannot.

Z11409

Same story from Mobil Factory rep.

rikhek

Ahhhh.... there's that elusive magic number, namely 320 degrees F. Redline, Mobil and the manufacturer, GM, state the magic number as 320. From the C6 owners manual:

ENGINE PROTECTION

REDUCE ENGINE RPM

This message displays if the engine oil temperature
exceeds 320°F (160°C). Check the engine coolant
temperature and engine oil level. If the engine is too
hot, see Engine Overheating on page 5-31. Your vehicle
may need service, so see your dealer/retailer.
You can monitor the oil temperature with the gages
button on the DIC. See DIC Operation and Displays on
page 3-50.

Multiple chimes sound when this message is displayed.
This message remains displayed and active until the
issue is resolved.

I'm so tired of reading posts from guys petrified when they see 260 degrees oil temp. Makes it even worse when they quote their "mechanic" tells them their car is destroyed....

Rick

AU N EGL

Still the lower the oil temp and coolant temp the better the car performs

and yes no higher then 260 is that magic number to shoot for.


an other good idea is to get the oil tested each oil change

"bob the oil guy" does a great job

quick04Z06

Ah, to have forged internal parts made from a very light, but very strong, alloy....