What oil should I use in my '88 Coupe?

[cajuncorvette]

I have a 1988 Corvette and need to know what oil and filter to use for my car. The previous owner used Castrol 10 20 40. I live in south Louisiana, and my local oil dealer is Pennzoil. Could I use Pennzoil? If so, what type?

There is a Mobil 1 oil change outlet close to me, and I have been reading the threads about Mobil 1. I have never used a synthetic in any of my cars. If I go with Mobil, is the synthetic what is recommended?

If so, does it matter if the previous owner did not use synthetic? How often must a synthetic oil be changed?

What should I use? I don't drive the car daily, but when I do it is a mix of highway and in-town driving. Thanks! 112K miles

 

[Baldie88]

It's me again, from your other post on what to do with the underside paint on your car.

You will get many different opinions on oil but for me the local dealer uses a Castrol synthetic blend. They switched over from a straight oil about a year ago. No problems with the switch. As for the Mobil 1, you don't need a straight synthetic blend for our L98 engines. I think the LT1 and later engines required Mobil 1. So just stick with your regular oil or a synthetic blend and you should be fine.

As to the brand of oil, I don't know if it really makes a difference, although again you will get many different opinions. I've used Valvoline for about 4 years and now Castrol for about 4 years. No problems with either one.

Ron
"Baldie88"

 

[cajuncorvette]

What weight?

Hi again, and thank you!
It is actually much easier for me to have oil changes made at our local Pennzoil dealer. What weight/type of oil should I ask for?

If I did decide to use Mobil 1 (regular -- not synthetic) and have the oil changed an hour away at the Mobil dealer, what type/weight would our C4's need?

I am without an owner's manual now, so I apologize for the questions.
Do all the regular (not synthetic) oils meet GM requirements? (You can tell I have read that somewhere!) Thanks so much! Cajun

 

[TedC]

The owner's manual recommends 5W-30 for your 1988 L98. 10W-30 would be a good substitute based on your warmer climate. My local corvette shop uses "regular" 10W-30 oil on L98s. Which brand oil? This is like religion to some, but I've never had internal engine damage because of the brand of oil I used. Use a high quality filter.

 

[Hib Halverson]

First, if you are considering a synthetic, all Mobil 1 products are synthetic. There is no "regular" or non-synthetic Mobil 1 branded product.

Be it petroleum-based or synthetic, the best viscosity to use in an 88 is 10W30.

Don't go the "synthetic blend" route as many of those products mislead the consumer because there is no legal or industry-accepted standard for how much synthetic is in a "blend". With some it might be as little as 10%. Some have more but there is little practical advantage in a synthetic "blend" over a straight petroleum-based oil.

If you want all the benefits of a synthetic, you need a "full" synthetic. Of those Mobil 1 is good but Red Line, while it is quite expensive, is the best.

The oil change interval for 88 was 7500 miles. As long as you use a API-rated petro-based or synthetic oil, you can change the oil at that distance or longer. Many synthetics lend themselves to extended drain intervals.

The best filters come from ACDelco, WIX, Bosch, Mobil 1 and K&N. You may find WIX the best combination of quality and price.

 

[Tuna]

I'm with Hib on this one.

I'm a Mobil 1 10w30 and ACDelco guy.

 

[cajuncorvette]

Thanks for all the assistance. I had my car serviced this morning. Used Pennzoil 10/30 and changed filter. I also had the system clean done. Thanks for your advice.