Would this make my truck run strangely?

[T?@\7]

Today I checked my oil, and added probably around 5-6 tablespoons worth of mobil1 high mileage 10w30 SYNTHETIC. I did so without thinking that the previous owner probably hadn't used synthetic oil. So would adding a little bit of synthetic to an engine full of dino (i think) make the truck VERY hesitant in gear, very chuggish, struggles to get up to speed but once rolling its good. But if I dont stretch 1st or 2nd gear more than usual, once I upshift it garggles again hesitates. Also, when cruising at a higher rpm and then letting off there was some what sounded like back firing, some popping in the exhaust.
I think I messed up

Thanks for your input.

 

[T?@\7]

ok, i started the truck up in the driveway and let it sit and idle, just to see what it would do.... I come inside, have a beer and go back 10min later to find it steaming like mad and I guess water boiling out of and inside the radiator....
wtf

 

[T?@\7]

broken t-stat, electric fan? fvck, and of course im supposed to be at work at 630 am lol

 

[T?@\7]

fan connection was somehow toasted, got a temp fix going on...... had me scared

 

[cometobanks]

Well, DID YOU MAKE IT WORK?!?!?!

 

[T?@\7]

oh yes! at this point, everytime I want to drive the truck I have to manually connect/disconnect the fan which is the case until this tuesday, when the oilpan gets replaced and the fan gets rewired