Originally Posted By: ZeeOSix
Originally Posted By: G-MAN
Just from my own observations, I'd say (at least on the C6 with the LS2 and LS3 engines), the Vette runs higher oil temps than a typical passenger car or light duty pick up. Even when the outside temp is a relatively mild 75F, I see oil temps of 230F+ on the Interstate with cruise set at 70 mph.
And let's not forget that GM first went to Mobil 1 as the factory fill (and recommended service fill) in the C4 when the LT1 engine was introduced and their stated reason was so they would not have to fit an oil cooler. That's tantamount to an admission that the LT1 in the C4 needed an oil cooler unless a synthetic oil was used, presumably because a syn oil can take the higher oil temps. As far as I can tell, there is no external oil cooler used on the C5, C6, or C7 Vettes.
My C5 Z06 doesn't have any extra oil cooling devices, but the Z06 does have a pretty good cooling system. The C5s have a digital coolant and oil temperature readout on the information center, and while cruising down the highway at 70 MPH on days around 75F I'd never see oil temperature over 210 F. Looking at a spreadsheet where I logged oil temp vs. engine RPM vs oil pressure, I never saw any oil temps over 220 F while holding the car at a steady 4000 or 5000 RPM for a couple of minutes to get steady readings.
Guys who tracked their C5 Z06 could see oil temperatures around 300F on hot days, and then decide to get an oil cooler (example below). His oil running at 280F in 90F weather seems a bit high to me ... maybe he's a real heavy footed driver on the streets. Could also mean his radiator needs cleaning, as the C5 was basically a vacuum cleaner how it picks up air going into the radiator along with lots of road debris, which eventually chokes down the air flow.
The 6th Gen Mustangs have a water to oil cooler block that the oil filter mounts to, and the "track package" has a larger radiator. The Mustang guys say on the track that the water-to-oil cooler doesn't help much because once the coolant temperatures increase due to laying down the HP at the track, the factory oil cooler loses some effectiveness (still better than nothing). Most guys who track their cars on a regular basis do cooling system mods and add a big oil cooler in order to keep oil temps reasonable during long runs on the track.
Mustang Cooling on the Track [LINK]
What kind of coolant temps are they seeing when the oil hits 280-300F? Thanks.
