rahoyme

The owners manual for my '85 L-98 says "use SF/CC quality SAE 10W-30, energy conserving engine oil". I had been using Mobil 1 5W-30 synthetic; when I used the Mobil 1, I had a slight oil leak from the valve cover gaskets. No big deal. But with the last oil change, I decided to use just regular "Mobil Super", conventional 10W-30. I noticed no difference in performance, and the slight oil drip/leak from the valve covers stopped. Now I'm thinking I should use the conventional 10W-30 from here on in. What are the thoughts and opinions on this?

DaleD

From what I've read, and opinions posted here, conventional is fine for L98s. Just have to change it more often. It's also been noted that synthetic is a smaller molecule and will leak out of places conventional won't.

Use the conventional, I would.

genefree3

Use the conventional, as often as I change oil I would need a second job to pay for synthetic. And I like my cars to be house "broken" Twice I have tried synthetic and both times they leaked like a seive. my .02 cents

BADDUCK

Use what your manual calls for. Mine has been on dino for 18 years, no leaks.

ynk1121

synthetic will not cause a leak that isn't there. It does however contain cleaners that will clean all the gunk built up in your engine. Sometimes all that gunk is the only thing stopping a leak to begin with.

CorvetteMike2024

I use Mobil 1 15-50 in my vette and harley. My harley runs 25 degrees cooler with syn. oil.

c4cruiser

I run Mobil-1 5W-30 in my 87 primarily because of track days. I usually see oil temps of 240-260 degrees toward the end of a 20 minute session and synthetic oil will handle higher temps without breaking down like a conventional dino oil would.

For normal street driving, a conventional oil works fine.

As far as cost, I buy the 5-quart jugs of Mobil-1 at Wal-Mart. They typically run around $20 per jug. I change oil twice a year so that really isn't a lot of money in the long run.

Johns87

Hello,
I use synthetic oil in My Vette and My Suburban. I use to reduce engine wear. I have not experienced any leaks with the synthetic. I too have noticed a little reduction in engine temps with the synthetic oil. I still change my oil every three thousand miles. Synthetic oil is a little more expensive but if you watch the fliers and stock-up while it is on sale, It's not that bad. It is also a lot cheaper than a new L-98 or 7.4 L vortec. Just My .02 worth.
You All Take Care, -John

rws.1

anything you can find just about anywhere on the shelf today is a higher qualitity oil than the SF specifed for you L98.
As long as the viscosity is correct you can buy just about any name brand or private brand avialable on the shelf in NAm.

hexane

"Oil is cheaper than engines." That's a phrase I've heard at least 4,000 times in my life. I use Mobil 1 Synthetic 5w-30 on both my Vettes. My 88 has 202k miles on it and it is working perfectly, leak free as well! I did an oil change on the "family C5" and used that weight as well. I also know that synthetic oil is less likely to sludge up when run hot. Its also provides better lubrication during those cold days on a cold start. This might be overkill, but I change the oil every 8,000 miles/8 months whichever comes first. No problems yet.

drippingwithgold

I use Mobil 1 Synthetic in everything. Lawn Tractor, Air Compressor.
My DD, is a 04 v6 Sebring Convertible has 190,000 miles and don't leak and uses no oil. Full synthetic will not sludge if overheated, also runs cooler and gets better mpg.

tomtom72

I would think that any name brand oil, dino or synthetic, is fine to use, as long as you at least observe the 3 mos/3k mile thing on dino oil. I use syn in my 90 even though it came with dino oil.

I believe the thing with the synthetic stuff is better lub performance at the lower & higher temps. My owners manual says that if "you use your corvette enthusiastically then using synthetic fluids are recommended." That kind of leaves me thinking that the synthetic stuff is better, well that and the fact that the factory after 90 went to syn oil as OEM. So I use M1 10w-30 full synthetic.

Also, fwiw, there is discussion about the lowering of (?) zinc phosphate(?) and it's effect on flat tappet motors. In view of that I plan to switch to an oil that meets the OEM specs for that substance. As I understand it the vast majority of motors in the more recent past, except for C4's, have roller lifters & cams so this old additive is less necessary. This is an EPA thing, I believe!

I can e-mail a link to some research that was done by one of the ZR-1 community's well respected tuners on this subject. Obviously, the thrust is toward our LT5's......however in MHO, a flat tappet is a flat tappet. I don't see much difference if it is OHC or cam in block...JMHO.

Red Tornado

i buy whatever is on sale, 10w-30 dino oil. i change it every 5,000 miles. every other oil change gets a $3 purolator oil filter.

Corvette Kid

Uh, most C4s do indeed have roller cams.....

xCCTer

I've never had an issue with leaking in either of my 'vettes using Mobil1.

redwing76

CorvetteMike2024

I agree with redwing

frenchyoliver

what about Mobil 1 0w40 synthetic ? I am using this one !

Red Tornado

frenchyoliver

here is the link

http://www.mobil.com/Canada-English/...il_1_0W-40.asp

It s advertise as the fastest lubricating cold oil.

It is working very good for me with zero leaks.

Anybody used this oil before ?

But may be I should not use it !