Synth blend or full synthetic for extreme summer?

Aug 8, 2005
stamford, CT
Hi all! Doing my oil change soon. I really wanna try Sunoco synth blend! Got that exciting itch. And am teeder toddering between that,and ....2 quarts 2005 era Pennzoil synthetic,( found clearance local napa earlier this year bought them) 2 quarts Mobil 1 10w30, and half quart leftover of 2013 Pennzoil PUP.
Summer here, lots stop n go traffic. Lots. Temps 97% F. Humidity pressure bad.
My question is....would the Sunoco synth blend hold up too all this and resist thermal breakdown? Or should I very much DEF,stay with synthetics for these conditions!? I really wanna try that how containers look remanisent if 90s Mobil drive clean containers! But got that feeling...I should be staying with synthetic.
Think for 6 months in aggravating traffic,heat, ect...Sunoco will hold up? I'll do about 3000 miles in that time.
At 110'F your car has a delta of 100 degrees between its radiator and ambient air.

At 80'F your car has a delta of 130 degrees.

Do you think your cooling system is sized so it can reject 30% extra heat compared to a "nice" day? They sell your model south of Connecticut. :rolleyes:

Just because it's uncomfortable for a human, that runs at 99 degrees, doesn't make it so for something that runs near boiling.

To answer your question, I'd run a complete change of one particular oil, and save the leftovers for the lawnmower.
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Lol. Okay,I knew I put too much info.just being honest n having a small story too tell..
Under these circumstances...would it be okay too run a group II synth blend oil,aka Sunoco oil? In 10w30...?
But..think it might go under thermal breakdown in those temps? The Sunoco group II synth blend?
Having spent a lot of time* in your climate, running carbureted cars on Dino oil, you can use whatever you like with an appropriate change interval and be fine. Southern CT is just not that extreme.

Give it a try. Have fun. No worries.

*Born in Granby, grew up in Bloomfield, and my daughter has been in New Haven for the past five years.
But..think it might go under thermal breakdown in those temps? The Sunoco group II synth blend?
Your oil temp will be so far from that. Even on the track at 80+ degrees my oil was at 270 which isnt hurting will be at 200 or so just driving around.
And if you are really worried about this, then get an oil that has documented oxidation resistance such as one with Porsche A40 approval.
As long as the Sunoco oil, be it a synthetic blend or a full synthetic is rated SM, SN, SN+, or SP it will be fine in your application.