oil weight

[95escahoe]

Hello I have a 95 Tahoe with 239k and change on it im currently using 10w30 castrol gtx high mileage, and have since I picked it up the previous owner used 10w30 too, the oil cap say 5w30 im pretty sure, I have had a few high mileage Mustang's and used the same weight cause heard it was better to use a higher weight oil if u have alotta miles on it, truck runs mint, doesn't use any oil, is 10w30 too high or should I use 5w30??? thanks for the help

 

[TahoeJim]

The only time 5w might help is if you live in a climate that actually experiences winter temps, below freezing. The 5w will circulate a bit faster during start up.

If you want to, do the next oil change with 5w and see if you detect any difference in how it drives when cold. Or just leave it as-is and keep feeding it what it's used to, 10w. I don't think you can make a wrong decision here.

 

[07Burb]

X2 what tahoejim said. Even here in Mo where it gets below freezing frequently here in the winter I interchange 5w-30 and 10w-30 from time to time

 

[IRQVET]

I've used synthetic 5W/30 and I was not impressed. The motor ran rough and had a weird sound to it. I changed to synthetic 10w/30 and I could feel a huge difference. It ran smoother and was quite.

Mobile 1 10w/30 Full Synthetic is the way too go !!

 

[95escahoe]

thanks for the info guys

 

[oldsalt]

I ran 20/50 for years with no problems but with this new engine my pressure skyrocketed and for some reason the lifters would chatter a bit starting up in the morning so I dropped down to 10/30.

 

[JonnyTahoe]

I like to think I'm the oil change king so this is what I run in my 95 5.7. In the minnesota winter I run what the cap says, 5W-30. If I lived in Alaska I would run that new Mobile 0W-20. In the summer months I run 10W-40 because with 190k it tends to use about a quart every 2500 mi. I change my oil every 2500 mi. because the TBI system is not as efficiant as the Vortec or the newer style injection systems and I get alot of fuel vapor in the oil so that's why I like to change it every two months or 2500mi which ever comes first. I just tried mobile conventional 10W-30 for the first time today but I usually use Quaker State, The "Q" stands for Quality and always will. I use to dump a half a quart of clean oil through the motor and let it drain out to "Rinse Out" what stays in the pan, but now I just let it drain till every drop comes out.

 

[AtomicHoe094]

how is synthetic more expensive? its 23bucks for 5 quarts compared to the 17bucks for 5quarts reg. but it lasts twice as long

 

[SunlitComet]

Here in Cali at oreilys Mobil 1 synthetic is $8.19 a quart right now. or a gallon for $30.

 

[JonnyTahoe]

I guess there are no walmarts in Ohio, 5 Qt. jug of most brands of conventional oil are about 12 bucks. Your local auto store must love you. Synthetic only lasts twice as long if you buy into the "Myth" that it lasts twice as long. I guess you like paying twice as much for the "Twice as long" filters too. Everyone has their own opinion on this issue so there is no point in going back and forth on it.