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I'm looking for opinions regarding a switch to synthetic oil.

I just purchased my '88 which has 65,000 mi. While I don't have a service history, the engine is not consuming oil outside of what I would deem "normal", nor does it have any leaks. When synthetics first appeared on the market I seem to recall hearing discussion to indicate that it would be ill-advised to put a synthetic in a used engine. Something to the effect that the stuff was so slippery that it would leak all over the place. True or false??? Or is it an issue that as long as I perform a good maintenance schedule that nothing would be gained by switching?

Any opinions would be most appreciated. Thanks.

I have never heard anything bad about switching. I think it is totally beneficial. I know that in the ZR-1's, it is recommended to make the switch to synthetic after so many miles........somewhere around 10,000 (from what I hear anyway)
I only run Mobil 1 in my car........hope this helps

And welcome to the CAC:)


Between my wife and I we have 6 vehicles, from an 72 Cougar to a 98 .... uh oh ....Mustang, Don't hit me too hard gang, all run on Mobil 1 and their filters.
Barry :upthumbs
Slippery stuff!


Make the switch to synthetic. Oil is oil. There seems to be some shroud of mystery or magic surrounding synthetic oil; it lubricates just like conventional oil, only better. The statement that putting synthetic oil in high mileage engines will hurt them is completely a myth. If you have leaking seals and gaskets with conventional oil now, or are consuming oil, you may consume and leak more with synthetic due to its higher flow properties and temperature stability. Flushing is your oil system is NOT neccessary when switching to synthetics. You may want to flush your lubrication system with a cleaner ONLY to get rid of the crud built up from years of conventional oil use.

I run synthetic in all my vehicles except one, including a 1981 Dodge 4WD pickup with 95,000 miles on it.

The one car I do not run synthetic in is my 1977 Datsun 280Z. It needs new rings and burns a quart of oil every 200 miles. Too much $$$ to be throwing out the exhaust using synthetic. If the orginal owner had used synthetic oil with regular oil changes, I wouldn't have this problem! :bash

I am curious as to what problem Keith's freind had with his vette.

JT ZR-Won,

The reason manufacturers reccomend using conventional oils in brand-new engines is to allow enough friction for break-in. Some synthetic oils have friction-reducers which work so well they will prevent ring-seating and inital wear for break-in of components.
Another thing. Don't think that just because you switched to synthetic oil you can go longer between oil changes. Change your oil at the very LEAST, every 3,000 miles.

Happy Trails!
We switched to Mobil1 synthetic in the 84 at about 35,000 miles (now 82,000) and had zero problems.......we even now use a 0w-15 and it does not leak at all...Do It! You wont regret it! The car runs alot cooler and seemingly smoother
I for one don't buy that 3,000mi oil change theory at all. Especially with high quality synthetics. I have used Mobil 1 synthetic and that is all the original owner used. Engine burns no oil and runs strong with almost 80K on it.
The oil filters on the other hand won't last with the oil.
With Mobil 1 I run 5,000mi. Change oil filter at 2,500.
I've converted to Redline Synthetic and they say extended drain intervals of 10,000mi in heavy duty use is ok.
I'm already 4,000mi into the Redline Synthetic and my oil temp stays stable. I don't live in extreme heat/cold or dust/dirt area.
The 3,000mi thing as far as I'm concerned is a great marketing ploy for all the quick lube oil change places to make a buck.
I'm sure I'll get a reaction from those comments but to each his/her own. If you want to change it every week that's on you.
To all who responded:

I got exactly what I expected and wanted...intelligent and knowledgeble commentary. All of your responses are indeed appreciated.

I "think" I will make the switch. First, I will continue to evaluate the current condition of the motor, and if the final analysis is good...it's a go.

Red Line, or Mobil 1?



Both are extremely good oils. Red Line is IMHO, slightly better, however, keep in mind that it is much more expensive than Mobil 1.

In my opinion, if you were going to be racing the car competitively, I'd go with RedLine....without batting eye. If you occasionally drive the car hard and really exercise that engine I think Mobil 1 is an excellent choice.

I have run Mobil 1 Synthetic in my '90 ZR-1 since 5,000 miles. I currently have 23,000 miles on it and have never experienced a problem. I do drive the car hard every chance I get, but it is not competitively raced where it sees extended periods of WOT (wide open throttle) use. Hope this helps. For more information on Mobil and Red Line products, check out our Corvette Portal and look under "Parts and Accessories" and then "Lubricants" for company information and links to the companies.
Just to follow up on Robs comments. I agree with that. Mobil 1 for most driving is just fine. I'm just experimenting with the Redline. You can get Mobil 1 for like $4.50/qt. The Redline cost me $6.95/qt and it is harder to find locally. Usually you find it at speed shops. The Mobil 1 you can find in most department stores or car parts stores. Surprisingly the best price I've seen on Mobil 1 happened to be a Walmart and Kmart, and they had the Mobil 1 oil filters too!
In the last 12 years I've either switched to or run on since new six cars:

65 Malibu (modified 400 cuin SBV8
71 BB Coupe (modified 460 cuin BBV8)
88 Beretta (2.8L V6)
95 ZR1 (modified LT5)
99 Blazer (4.3L V6)
01 Camaro (3.8L V6)

The two oldest were run on Valvoline petroleum-based oil, then on Mobil 1 then, about 1990, switched to Red Line. The ZR1 came new with Mobil 1 and was switched to Red Line (first 10W40 and now SAE30 Racing oil). The other three were run on the factory fill oil for 500-1000 miles then were switched to synthetic.

The 99 Blazer and the 01 Camaro use Red Line 10W30. The drain interval is every 16,000-18,000 miles with a filter change every 3000-4000 miles.

The 88 Beretta was run the same as above but I no longer own the car.

The Malibu uses Red Line 10W30 and the two Corvettes use Red Line 30 Race. All three are changed about every 10,000 miles or two years.

The 88 Beretta was once a part of a Red Line Oil extended drain interval test. It went 140,000 miles using extended drain intervals which usually were16,000 but went to 22,000 miles in one case for testing. The last oil analysis was done at about 140,000 miles before the car was sold. It's data shows the engine to be in outstanding condition for being 12 years and 140K miles old.

Bottom line: synthetics such as Mobil 1 or Red Line work well in older vehicles as long as there's not a pre-existing high oil consumption problem.

Thank you for your response. I've made the decision to switch. The engine is not consuming oil nor leaking, so I should be fine. The benefits seem to be exceptional.

Racer78 said:

What oil do the NASCAR Winston Cup boys run in their engines for 500 miles?


Great question. What the Cup guys truly run in their cars is pretty much known only by those in the motor shops of each team. I do know there are Cup teams that use Red Line Race Oils but I don't know specifically which teams those are. I also know that Red Line, on a special-order basis, packages their racing oil (not sure what viscosity) in unmarked 5gal. pails for a big distributor in the southeast which sells to Cup teams on a cash basis. I'm told by sources that this peculiar packaging is for teams who are sponsored by major oil companies but that do not use that oil companies product(s) in their engines.

Lastly, Red Line sells a lot of light viscosity versions of their race oils and gear lubes to Cup teams for use in qualifying engines, transmissions and gearboxes.

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