High Mileage Oil Blend?

[Muskoka]

I recently purchased a 1996 GMC Yukon (5.7L Vortec) with 118000 miles on the clock.

 

It has probably been run with 5W30 from day one, but my mechanic who did a transmission flush today has recommended higher blends for the miles on it: 10W30, 15W30 maybe even 10W40.

 

Is this sound advise? His suggestion is Quaker State Higher Mileage because it has all of the additives in it already, and says that for a truck of this mileage he does not recommend full synthetic as it runs too thin.

 

The truck does have a slight lifter tap, but nothing outrageous.

 

I'm not so concerned about the brand as I am about the blend and the dino/synthetic comments.

 

What's the take of the masses on his thoughs?

[bigtruck21]

depends if the truck burns oil yet or not. If it's not leaking or burning, run what the manual calls for 5w30 or 10w30. If it is leaking past the valve seals, a thicker oil will be a temp fix. I used valvoline maxlife in an old truck, but the leaking got worse over time, so the product didn't stop it very good. I put amsoil 10w30 in my dad's 95 454 with 100k and this was the first time it's seen a true synthetic. I did an engine flush and it has yet to start leaking in 4 months and a couple thousand miles. Knock on wood.

[Black02Silverado]

If your not having any problems with it leaking now or using oil then stick with what the owners manual calls for.

As for the high mileage oils they have not been out all that long. So I have not heard good or bad on them. I would stick to the regular stuff.

 

As for synthetics. Bigtruck21 is one user of synthetic that is having great results. Synthetics have come a long way. There are a lot of users out there that have 100, 200 and 300k miles on their engines and are running synthetics with no problems. I had 120k on my Sonoma before I sold it and it was running synthetic with no problems. I have to admit Amsoil has been around over 30 and was the first to come out with an API synthetic so the technology has advanced with the changes in these newer engines.

 

If you do switch to synthetics remember to flush before you install. It helps clean out inside your engine and prep it for the synthetic.

 

Synthetics clean really well, and might take care of the lifter tap. I had a few that had that problem and switched to synthetic and the tap went away. It doesn't hurt to try. Also you can switch back to regular oil if you feel that synthetics are not doing anything different for you.

 

If you want to go to bobstheoilguy.com and check out what everyone on there has to say. There are a lot of good posts on there of what does and doesn't work.

[NewEnglandDmax]

Let me ask this stupid question, What is an engine fush to prep for Syn oil? I just drain the old and change filter, right? Thanks all.

[bigtruck21]

It's basically a bottled detergent that eats all the gunk away because dino deposits have low viscosity index and will sludge up in places. Otherwise the synth oil will eat this and the oil won't work as well and will clog up the filter. Amsoil makes an engine flush and someone else said there is another product that works slower and is supposed to be safer for the engine. Do a search in these forums. I forgot the name of it.

found it

http://www.gm-trucks.com/forums/index.php?...showtopic=19819

http://www.auto-rx.com/

[Black02Silverado]

Let me ask this stupid question, What is an engine fush to prep for Syn oil? I just drain the old and change filter, right? Thanks all.

There is no such thing as a stupid question. To me the only stupid question would be the one that was never asked. How else are you going to learn about life if you don't ask, right?

 

The engine flush just helps to get out of the engine what it can of the build up that has collected over time. This way the synthetic oil will have a cleaner engine to work in and not be busy cleaning out and filling up the filter itself.

 

My general rule is anything under 30k is safe without the flush if the oil has been changed at every 3k.

 

Amsoil's flush just gets the light build up out and hold it in suspension till you drain the oil and remove the filter. It will not remove the varnish like build up. With it all you do is remove your old filter, install a new filter, this removes just the right amount of oil so when you add the can of flush it isn't over serviced. Then run the engine at idle for 25 minutes. Shut it down, drain the oil and remove the filter and your ready for the new filter and oil.

 

If you really want to clean the engine use Auto Rx. That stuff is amazing. It is really safe and cleans really well. To use it you put a new filter on your vehicle and add the 12oz bottle of Rx to the old oil, then just use the vehicle like normal. When you reach 750 miles with the Auto Rx in just change your oil. If you have a high mileage vehicle, one with over 100k on it then they recommend changing out your filter half way between. You can also change your oil and filter then add the Auto Rx and drive it for the 750 miles then change it out.

 

I used the Auto Rx in my father-in-laws Eldorado and his oil consumption went down by half of what it was using.

 

If you want to read up more on Auto Rx you can go to it's site at Autorx.com or read what others have to say at bobistheoilguy.com

[speedshifter]

I use Castrol Syntec Blend 15W-40 Truck Formula in my 350. 120k miles and still running strong. The nice thing is the stuff only costs $2.1? a quart not $5-$6 like the full synthetics.

[SilveradoWV]

I have used the STP engine Flush (Off Road Diesel Fuel????????) on the '91 350 my dad used to have and before I could look in the oil fill and everything was stained and dirty, after the flush everything was clean and shiney. It had 5w30 in it ever since it was new and it had about 170,000 miles on it when we sold it, no leaks!!!