High milage vs synthetic

[Ilivalidle]

2007 Avy with 5.3 flex, 125,000 miles. High milage, semi synthetic or full synthetic oil. What do you recommend?

 

Thanks for any suggestions.

[kstruckcountry]

I use full synthetic in my 2006 5.3. 122k miles

[DwayneJ]

99% of replies are going to be based on brand loyalty and marketting. If YOU like something go ahead and use it without trying to rationalize.

 

Lubricant related failues are a thing of the past, the very distant past.

 

Maybe I can end the "I have 100K miles on mine running xxxx" comments by saying my wife's Chevy has had dealer quicklube bulk oil at the OLM indication and has over 225k miles with no indication of trouble yet.

[zach1990]

^^^^ nailed it. But I will add my family has had 2 sierras over 300k miles with castrol gtx 10w30 just for DwayneJ

[Daryl LBZ]

Synthetic.

[Crf450r420]

High milage oil has more additive to condition seals or in other words swell the seals so the keep working. This is not needed for silicone seals that are used throughout the LS platform.

[Jsdirt]

Just my opinion, but full synthetic or dino. Anything in between is a marketing gimmick.

[DwayneJ]

Some of the synthetics sold in the US are group III not true synthetic which is group IV or V. Some can actually work very well.

 

If someone wants to split hairs they can either do Used Oil Analysis or read up on results people have with the same vehicle use report from their UOA results.

 

Pretty much everything these days is good quality, but sometimes one oil might provide better or worse results in a particular engine.

 

A decade or so ago I used to spend a lot of time on Bobistheoilguy forums the 90s LT1s were my thing and everyone outside that forum "knew" M1 5w-30 was best for that motor because it was what GM put in the LT1/LT4 Vette. Never saw a M1 5w-30 result for an LT1 that looked anything above mediocre, iron numbers in particular trended high. But say a Castrol Syntec 0w-30 that was actually a fair bit THICKER at operating temps showed much better results despite being outside GM recommendations.

 

That M1 that was not so great in the LT1 though turned out fantastic results in a VW 1.8Turbo motor.

 

It was a good product but just not the best fit for the application.

[GPGuy]

I switched to full synthetic on my last oil change and my engine is running smoother now than it has in a long time. 102k miles here.

[eddietorn]

It has to be pure synthetic oil, anything in between will just have contaminants. I personally use Mobil 1.

[DwayneJ]

It has to be pure synthetic oil, anything in between will just have contaminants. I personally use Mobil 1.

You are a marketing department's DREAM. besides the fact M1 has not proven to be that great in LS motors.........

 

It is quality oil but not worth drinking the koolaid over.

I say this having filled my truck up with it Sunday, I bought it because Advance had it on sale, $3o after mail in rebate with a M1 filter.

[dbbspider]

I have 178k miles on my 04. Right now I have full syn oil in it. Before that I had conventional oil in it. Trucks runs smooth, no knock, no leak, no eating oil. I buy and use what ever is on sale, including supertech from Wal-Mart and local auto parts store brands. It's more important to change ur oil when required than type or brand.