I'm looking for opinions from C4 members on what type of oil I should use in my 1988, stock condition, 100,420 miles and runs exceptionally well, at least to 130MPH. I have considered using synthetic Mobil 1, but was told by a a auto parts salesman that synthetic oil would not be a wise choice. I NEED FEEDBACK!!!  Thanks.  

|UPDATED|8/20/2017 9:48:03 AM (AZT)|/UPDATED|

I just went with Royal Purple full synthetic as this was what my mechanic carries.  I was nervous about going to full synthetic as I heard it would cause a leaking problem?  He said not to worry.  With the heat that these motors run at it would seem full synthetic would help.  Why mobile one would cause a problem is a mystery to me.  I have used mobile one in many of my prior cars.  Take care!!!!

How many miles on the engine, and what type of oil is being used currently?

With that kind of mileage, I'd keep using what your using. No pun intended!

I've always use Mobil 1. Synthetic in my 1994 C4 Coupe she has 85 K and trust Mobil 1 Synthetic. Never any problems and I run it for 7500 miles between changes....The person might have been try to sell you some new oil that is more costly... A sticker under the hood of my vette says to use Mobil 1....

Whatever your Owners Manual calls for. I have a '94 LT1 and a '96 LT4 (with over 193k miles, stock) and use Mobil1 exclusively - that's what the sticker under the hood says and it's obviously worked.

How is your car driven?

Don't spend extra $$$ on a motor oil if you don't spin your engine above 3000 RPM. Daily cruiser or weekend tourer, regular 5w30 is fine. Ask the previous owner what he used, then stay with that if the engine runs fine. If less than 3000miles/year, change oil and filter annually. I prefer Wix filters myself, just stay away from Frams.

There's a lot of variables here...the main thing is don't be talked into spending more money for oil than you need.

Ive been using MOBIL 1 10W60 Track/High mileage oil for many years and 100k miles in my '87. its a great oil and perfectly suited to the L98. I change it every 20k miles or two years as my car is used every day for pleasure and the commute.