Which oil, conventional, synthetic, or blended?

Mike92GT

Founding Member
Jan 23, 2002
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Florida
I've always used conventional oil in my cars, but the premature failure of my current engine has me thinking about going synthetic. What do you guys think? I'm not real concerned about the extra cost, as the car is an occasional driver. I hear that synthetic is much more likely to cause oil leaks. How about the blended stuff? Seems like a good compromise.
 
Was the blown DSS engine in your sig the one that failed? What happened to it? It's EXTREMELY rare that the oil itself is the cause of a failure.

Possible leaks is more of a potential issue when a high mileage engine that's been run on conventional oil is switched to synth. You shouldn't have that problem with a new motor provided it's sealed properly.
 
Michael Yount said:
Was the blown DSS engine in your sig the one that failed? What happened to it? It's EXTREMELY rare that the oil itself is the cause of a failure.

Possible leaks is more of a potential issue when a high mileage engine that's been run on conventional oil is switched to synth. You shouldn't have that problem with a new motor provided it's sealed properly.


Yeah, sadly it's my DSS motor that failed. Only had 40K miles and the main bearings are all wasted. Pics here:

http://forums.stangnet.com/showthread.php?t=620919
 
srothfuss said:
Run synthetic if you can. Like everyone is saying.

My car requires the dino blend (I don't want to create any more small drips)

Disconnect your PCV and install a crankcase breather and try again. You'd be surprised. Both my 143K 302 and my girlfriend's 154k tbird 302 were both oil fountains until I switched to a breather system and barely a drop every few weeks now on both cars. Its amazing what a difference it makes.

You need to give that blowby a path to exit the engine.
 
I would disagree a bit on the breather suggestion (they are only a last resort IMHO, and there are other options).
The PCV actively 'sucks' crankcase vapors out, where as a breather is rather passive, simply expelling pressure when there is enough delta.

The 'scavenging' effects of the PCV are worth it to get that corrosive vapor out of the crankcase........

Just MHO.
 
HISSIN50 said:
I would disagree a bit on the breather suggestion (they are only a last resort IMHO, and there are other options).
The PCV actively 'sucks' crankcase vapors out, where as a breather is rather passive, simply expelling pressure when there is enough delta.

The 'scavenging' effects of the PCV are worth it to get that corrosive vapor out of the crankcase........

Just MHO.

This is true but in my experience, when you reach 150k or so, the amount of blowby you can get from a spirited peg of the throttle far exceeds what the pcv can "suck" through that small hose and you get a pressure spike and some oil goes bloop out the side of the engine or out the dipstick.
 
Yeah, I've been going back and forth about the PCV / breather thing. I actually had breathers and no PCV on my last motor, but it didn't last very long. So now I'm thinking I'm gonna go back to a PCV system with an air/oil separator. It's gonna be a new shortblock, so hopefully blow-by and leaks won't be too bad
 
Newly mounted air / oil separator

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Old breather / catch can set-up

IM000037.webp
 

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Mike, if you had it built to take synthetic from the get-go, you would know it (there is slight machining that is done differently).

Another vote for dino for a bit, then switch.