I changed the oil & filter today in my '04 Silverado LS 5.3L 2wd. I used Mobil 1 5w30 and a SuperTech (Wal-Mart) oil filter. I have used this combo in almost every vehicle I have driven during the past twenty years or so - with good luck so far.

I bought the truck used in February with 75,000 miles on it - and soon changed the oil & filter (as I always do when buying a used vehicle) at just about 76,500 miles. I used Quaker State 5w30 dino oil and a Wally World filter. Now that it has been ~ 3,000 miles since that oil change, it was time to it again - but with synthetic (which was on sale at Costco).

The old oil still looked as though it had life left in it, but I am taking a long trip out the Midwest in a few weeks.......and wanted the truck to be prepared for almost 2,000 miles of driving within about a week.


After changing the oil & filter, I checked for leaks, ensured all was well and then went to top off my gas tank. I added a bottle of STP fuel injection cleaner and jumped on the highway for ten miles of "high speed" operation. Immediately, I noticed the temperature gauge was running a bit cooler. Normally, it is right up in the middle - but now runs a bit cooler. Is this normal with synthetic oil? No other vehicle I have ever owned had a different reading on the gauge after switching to Mobil-1.


Just wondering.

 

I have never herd of that. But I guess ya never know. maybe the oil you used could get some of the heat out faster. I would say you would have to run it for a longer amount of time to see what the temp is after a long drive. the temp should depend on your cooling system.

 

It is running about "one or two notches" cooler on the gauge after I switched to synthetic; and the outdoor temperatures here have been HOT HOT HOT lately.

Even so, this truck always runs cooler than most other vehicles. I can practically put my hand on top of the engine after driving it all day long (my old Mustang GT was like that). My other vehicle is a Nissan Sentra, which runs a lot hotter than the truck - probably because it has a little four-banger in it.

I'll have to keep an eye on it, but do feel good about running Mobil-1 in my truck. Synthetic oil has served me well in several vehicles, even though I probably still change it more often than I should. ==> Cheap insurance & peace of mind, eh? <==