engine oil Should I switch my high mileage truck to synthetic oil?

[whydoIneedaname]

I recently acquired a 2007 Chevrolet Silverado 1500 Z71 (5.3L, 4 Speed Auto). I purchased it from my grandpa who babied the truck, and put 191,000 miles on it.

 

It has had a shockingly small amount work done over the years and drives like brand new (he kept all of the receipts). He always goes to the same shop which uses a Mobil 1 Extended Performance filter and Valvoline 5W-30 conventional oil. Now that it has 194,000 miles, should I change the oil to a synthetic blend, or full-synthetic oil? Also is it wise to use a high-mileage oil?

 

I changed my wife's car to synthetic oil with great effect (and I realize it is a completely different situation considering she has a lower miles car, but I just wanted to express that I was open to the change).

[CamGTP]

Everything out that says conventional is a synthetic blend oil already. The standard 5W30 Valvoline says it's a blend oil on the bottle.

 

So just stick with the same stuff if it's been working for this long already.

 

https://www.valvoline.com/our-products/motor-oil/daily-protection-conventional-motor-oil

[Colossus]

You cannot harm the engine by switching to a full syntheic oil.  Give it a shot.  Go full synthetic get a good oil filter, and see how she purrs. 

[Silverado/Sierra guy]

The Valvoline 5W30 is a good quality oil. I’ve been using the high mileage Pennzoil 5W30 and I’m happy with it.