J W Drew

Recently bought a 85 Vette. 88000 miles. Don't have a history on service. What do you reccomend, synthetic or regular? 10/30 or 10/40? Seattle weather.
Thanks

Nathan Plemons

I run Mobil 1 10w30 in everything I own. If it has never had synthetic there is the possibility that switching will cause oil leaks, but that just means it's doing it's job cleaning out all the crud that's stuck where your gaskets used to be.

TorchTarga94

I would personally use Synthetic 10-30. I don't believe you will develop any leaks. If you are hesitant you could always use the full synthetic high mileage Mobil 1 that has seal swelling agents to help prevent leaks (That's what I use).

rocco16

In no catagory is conventional oil the equal of synthetic....unless, of course, you have to consider price.
I'll bet you dollars to doughnuts your 1985 already has an oil leak or two, so I wouldn't worry about that aspect....

Larry
__________
not easily impressed....

96 Vette CE

**Facepalm**

FOURSPEEDVETTE

Don't put synthetic oil in your 85. They were not designed to use it. It will absolutely leak around the valve cover gaskets with that stuff. My engine was completely drip free before I changed the oil to synthetic only because I know it works very well in my NEW cars. Two days after I put the synthetic in, the valve covers were leaking. The valve cover gaskets were only about 1.5 years old and definetly tight. I immediately switched back to Castrol GTX 10W30 conventional oil and the drips stopped on their own. That's all I needed to tell me not to use synthetic oil in my 85. Don't waste your money.

Nathan Plemons

Personally I'd rather change the valve cover gaskets or deal with a small oil leak as opposed to using an oil that doesn't protect as well.

96GS#007

Biker

I've seen several instances of synthetic oil leaking from older vehicles. Not saying it will happen, but it can.

I don't use synthetic. It's too expensive and I have too many crankcases to fill (4 cars, 2 motorcycles, ski boat). I've heard good things about synthetic, but I've had no compelling reason to switch. In my 30 years with motors, dino has worked just fine.

FOURSPEEDVETTE

It appears that this member is new here and is new to C4's. Give him a break. This is a good question and will always come up because new members don't know what the "search" function here is yet. To the new member, it's the section across the top of this page. Click on "search" and enter your question or topic. Many answers can be found here without waiting for someone to reply to your question.

Biker

What's worse than old topics is folks who knowingly open them and post wise cracks, smilies and suggestions to use the Search function. If you have nothing to say, say nothing.

FOURSPEEDVETTE

Mr. Peabody

JW consider going to the Pacific NorthWest section of the forum and posting this same question there .... mention that you would be interested in the view of "TJ Wong". Tom is one of the top corvette tuners & engine builders on the west coast and has owned C4's himself. Many of us who have had internal engine work done on our Vettes of all generations have taken them to Tom and he is very well respected.

Not saying that you won't get the right answer here but he is another source you can count on who has had more hands on experience than most individual owners and who will give you a straight answer

96 Vette CE

That's great advise but a lot of these "new" members aren't so new at all and just start these threads to stir the pot. Being a member here for the length of time that you've been, you know these types of threads just end up in people arguing and getting closed.

I'm not saying the OP is trolling, but the information being asked is easily found in your owners manual.

Save The Wave

Alan777

How does a synthetic vs conventional thread stir a pot. I'm willing to bet 90% of the new threads are repeats.

OP, there's no reason not to run synthetic. Longer change intervals, and better protection against high oil temps.

96GS#007

Forum LEO?

A few of the 134 threads in the C4 forums...

http://forums.corvetteforum.com/c4-g...hetic-oil.html
http://forums.corvetteforum.com/c4-t...hetic-oil.html
http://forums.corvetteforum.com/c4-t...-best-oil.html
http://forums.corvetteforum.com/c4-t...use-in-c4.html
http://forums.corvetteforum.com/c4-t...ional-oil.html
http://forums.corvetteforum.com/c4-t...gular-oil.html

Search Google and the sky is the limit.

To the OP...which one is the "right" one...which ever one you are comfortable with, especially with a car that is for pleasure only. If you plan to race it....auto-x or road course...synthetic.

J W Drew

Did not mean to start a war here. Yes I am a new member and feeling my way around. I am not new to racing and Corvettes, having owned a 64 and a 78. Also owned and raced an Unlimited Hydroplane. Thanks for all the good advise.

Tommy T-Bone

Synthetic blend

BSenzina

I have an 84 with 57,000...I use Royal Purple......no leaks.....

delphipgmr

i only use a synthetic blend in my 87.