jtblckmaro

Hey guys,
I have a '95 3.4 with 170,000 miles and climbing. Every weekend I drive from Atlanta, GA to Evansville, IN. That's a 6 hour drive twice a weekend. I've been changing my oil every other weekend with GTX hi mileage. I've been researching synthetics on here and am thinking of converting. I'm thinking that the synthetic will be better for the motor on the long drive since it doesn't get a rest from the heat for 6 hours straight, and maybe I won't have to change it quite as often. I'm hoping to be able to lengthen the time between oil changes to maybe once a month. Just wanted to get some input on it.

Thanks!

tom2

I suppose you'll get different opinions on this but I wouldn't use the syn. oil in it with that mileage. I put synthetic in two differentials last year, figured it was a one shot deal so the extra money wouldn't hurt. Both rears looked like new, no wear at all apparent. Wound up replacing pinion and axle seals in both right off, then got a noise in one, the pinion bearing was shot, and I noticed the spider gears were really shredding metal too. The lube might be great in new stuff, but I'd avoid it in the really worn in and older machines. I'd stick with the high mileage oil and run it a bit longer since your driving is mostly highway.

V8 Slayer

I agree with the above, it will also leak like a mother****er!

ImportKILLER

I currently use synthetic in my '96 with 148,xxx miles with no problem. I started using it when I first got the car (got her with 60,000). At the time, it had a small oil leak problem. Using synthetic, I saw no additional leaks. Since that time, leak has been fixed and no further problems.

With that said, because it is straight driving (I'm assuming little stop & go or idling), you could push your conventional oil further than the traditional 3,000 miles. If you don't mind the extra $$$ for synthetic, you'll get better protection and you can push it further before you change it out.

I do roughly 90% highway miles and do 7,000 mile oil changes on synthetic. I've done oil testing which has shown I could push it even further, but I like the 7k changes.

Good luck.

MarineReconZ28

I went to syn. a few months ago, and I have had a huge leak ever since. I'm going to tear it down and put new selas in everything sometime soon. I already went back to conventional oil and that helped a little with my leaks. But the day after I put the synthetic in, I had leaks. I drove it once and was pissed. I had 118k mi. on it.

70GTO

I switched my wifes 2002 Montana minivan that has the 3.4 v6 in it to synthetic when it had 20,000 miles on it & it started using oil. Turned out the intake manifold bolts were not tight " A new set of gaskets & problem solved" It wasnt really a fault of the oil that it started leaking, but that's how it happend to end up.
My 95 Camaro that has the 3.4 v6 had 85,000 miles when I bought it & got right at 24 MPG. I swapped it to synthetic oil a couple of thousand miles later & it got 28 mpg "no other changes" It now has 127.000 miles and leaks no more now than when I was running regular motor oil. I change oil & filter every 5000 miles and it still doesn't use any oil "also the oil stays clean". Personally if it were mine I'd try it, but the others here have brought up some valad points, so the ultimate decision is up to you.

Best of Luck "which ever way you decide"

Bruce

jtblckmaro

Well guys, I'm glad I posted up here before making the switch. I already have a small oil leak I'm thinking from behind the intake manifold so I'm not going to invite any more until I have the money to throw around experimenting with fixes.

Now, ImportKiller, you said that since it was straight highway driving I could push it farther than the 3k interval. The constant heat on the motor doesn't deteriorate the oil? I was assuming that I needed to change it more often BECAUSE of the highway driving. (But only because of just how long the drive is, like I said before 6 hrs of heat pounding on it.)

Thanks for all the inputs!

Dave89IROC

highway miles are easier on the oil then stop and go

if you check your owners manual, it probably say "normal service" mantinance is at
5000 miles, and "severe service" which includes stop and go, is 3000 miles

MarcR94v6

I remember someone saying something about older engines getting small cracks in the old, worn parts, and the synthetic getting sucked in all the cracks.

ImportKILLER

Highway miles are easy on engine oil. The RPMs are constant and it keeps a stable temperature. Short trips and extreme temps (extreme, not operating temps) kill oil.

I wouldn't sweat the time aspect of your driving. If you want, do an oil sample test to see how your oil is holding up. I'd imagine you could push conventional oil in your driving situation to 5-6k, making sure the oil level is maintained.

jtblckmaro

Cool
Thanks alot guys, I appreciate all the info!

zephxiii

I run synthetic religiously because it IS superior.

1995 pontiac trans am, 118k miles. After i put synthetic in it, the engine just feels a lil smoother. No leak problems.

I had a 1986 BMW 325es with 235k miles on it. When i first put synthetic in that car, there was a huge difference on how the engine felt. It ran so much smoother. I never had any problems with synthetic leaking in that car.

I recommend mobile 1

Do you put liquid gold in your engine? If not, you should.

jtblckmaro

Never heard of liquid gold. What is it?