I read through all the prior octane posts, and couldn't find the answer I seek.

Will the engine run cooler using higher octane?

I ask, because the price of hi-test (92 or 91 whichever) has plummeted here by over $.60/gal. In light of that I splurged and filled with hi-test rather than mid-grade this past weekend. Car is running like a screaming banshee, I mean that 4.5 really likes this stuff. Anyway, I noticed, starting Sunday, that the coolant temp has been consistently 5+ degrees cooler than before (now showing right about 185 rather than 190).

Coolant has shown a constant 190 or so since reworking the radiator, hoses and T-stat. I have run this engine on all grades of gas without any knocking or pinging, seemed to run good on mid-grade too. But the way this thing likes the hi-test, I'll probably just keep burning that - WOW .

PS: Mileage is looking great too! A little over 200 miles, combination driving and still above 1/2 tank.

__________________
Mike Tangas
'73 280SEL 4.5 (9/72)- RIP
Only 8,173 units built from 5/71 thru 11/72

'02 CLK320 Cabriolet - wifey's mid-life crisis

2012 VW Jetta Sportwagon TDI...at least its a diesel

Non illegitemae carborundum.