alright heres my problem. i got this 91 dx with a ls motor in it, and the guy tells me to only use synthetic oil in it. i thought that was a little weird, its an old motor, but it hasnt leaked any oil so i havent put any in, and i need to do an oil change, and im wondering if i put synthetic or not. i heard that once u put synthetic in, you cant go back to the regular stuff. is there a way to tell if the oil is really synthetic. the only reason i ask is because the guy lied about a lot of stuff to make it seem better, so im thinking maybe he lied about this. anyways so should i just put some synthetic oil in it? im afraid its not synthetic and when i do put it in my gaskets are all gonna leak n sheit. any help pleases

 

I heard the same thing about synthetic oils. I heard u cant go back once u use it, cuz your engine depends on it. I was told that u dont want to use synthetic oils in an older engine. All the seals and stuuf would leak. This is what I was told, I just wanted to help out, if im wrong someone correct me. good luck

 

I can't help on the technical side of the oils but I do think that the regular oils are "thicker" which helps maintain the seals and gaskets better...I 'think' that with synthetic's it being thinner, where around some seals the regular thicker oil would not leak (as much) the synthetic would.
Personally I use Castrol "High Mileage" anyway, it's what the oil was designed for...it's a little more expensive...but if it saves/helps my engine...

By the way...if the "guy" you referred to is your mechanic...and he's lied to you before and you can prove it...why the hell are you still going to him!?!?!

Hope the offers a little help...

Jason :rockon:

 

Maybe a synthetic blend would be better than full synthetic.

 

menappi,
The old myth about swapping synthetic and organic oils is just that, a myth. Most of it comes from the fact that many synthetic oils (RedLine for example) have an excellent additive package that will actually help clean out the inside of your engine. Back when these oils were first becoming popular, say in the early 80s, there were some seal problems that caused leaks...I wouldn't worry about it now at all...after all, they do *blend* synth and organic oils, right. I've also swapped between synth and organic in my CRX without problems.

Without knowing what kind of oil is in there, it would be difficult to tell, even from a used oil analysis exactly what's in there...I'd say it's not too important. Use whatever oil you want that is the proper grade for the engine and environmental conditions and you should be fine.

Bogatyr