motor oil question

[Nbudinich]

I heard from somebody (you know how that goes ) that once you put synthetic in your engine you can never switch back the fossil. He said it is very bad on the engine, something about ruining the seals? Anybody know anything about this.

[Butch 02 Denali]

That's an old myth that has very little truth in it. Synthetic oil cleans the engine way better than dino oil does. If your engine seals were all clogged up with gunk, the synthetic would wash it all away, and your high mileage engine could leak. Don't be concerned on any newer truck.

 

Butch 02 Sierra Denali

[superbee]

It's a wives tale.

[Nbudinich]

Thats what I thought. I switched back and forth a bunch of times in my last truck. Some times I don't have the money for the good stuff. I didn't want to make any mistakes with my new toy. Thanks a bunch for the response.

 

[vortec350]

Who ever tells you that you can not change back and forth is an idiot,dont listen to them.It will not hurt it at all.

[snoman]

Who ever tells you that you can not change back and forth is an idiot,dont listen to them.It will not hurt it at all.

THis is not quite true. While it is completely safe to switch from synthetic to conventional it is not wise to switch from conventional to synthetic in high milage engines. The main reason being that synthetic cleans a lot better and it could loosen up a bunch of "dirt/sludge" in short order and possible damage engine if build up is of a signifigant amount. You might just switch to a synthetic blend oil (usually 20 to 30% syn) and stay with it long term as they can be had for around 2 buck or so a quart. BTW I have a 89 4x4 suburban with 170,000 miles that has had Mobil One since day one and it does not burn a drop today and is quit as can be and still runs like new. I also put well over 200,000 on a Toyota using it for the first 170,000 miles then switching to blended oil. It was still running great when it was totaled regretably as I wanted to get it to 300,000. plus.