That whole "no synthetic oil for old motors" thing - Vintage Mustang Forums

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post #1 of 8 (permalink) Old 03-21-2003, 04:04 PM Thread Starter
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...because of potential leaks.

Some of you may remember that I asked a lot of questions a couple months back about changing my 182,000 mile engine over to synthetic oil. Then after I took the plunge, I updated everyone that I really did notice an improvement (smoother idle, etc.); but those leaks I had been warned about had started. Wherever it was coming from (on the bottom half) was blowing all over the belly of the car! I didn't let it bother me too much because I figured the benefits of synthetic were worth the mess.

Well, for some unknown reason, the leaks have stopped. And no, I haven't just lost all my oil I thought of that too, and already checked! No more drips in the garage and no more blown back oil on the transmission. Can't explain it.

Any ideas?

Danny Johnson
1966 hardtop: 289 4 bbl; 4-speed; Nightmist Blue with Palomino standard interior
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post #2 of 8 (permalink) Old 03-21-2003, 04:23 PM
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I experienced the same thing you have, No answer but not complaining either

Gary B

If It Ant Broken You Aren't Trying Hard Enough ( Red Green )
Duct Tape has Replaced The Dog As Mans Best Friend. Just Ask Red Green
69 Mach 1 ( Molly )
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post #3 of 8 (permalink) Old 03-21-2003, 04:28 PM
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I started putting synthetic in my 300 I6 at around 120k-130k. It started weeping oil more than with dino oil. It started leaking bad about 5k ago and I had to change the side cover gasket. Now only the front and rear main seals weep. I'll stick with synthetic.

In Thrust We Trust.
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post #4 of 8 (permalink) Old 03-21-2003, 04:44 PM
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Same problem here. I rebuilt my original 289 last summer and have been running synthetic since. I started with 30 weight, but it leaked a little around the harmonic balancer seal. Went to 40 weight, still leaked a little, then suddenly stopped. Been good ever since *knock on wood*. The stuff sure is slippery and will find ANY leak you missed [IMG]/forums/images/icons/smile.gif[/IMG]

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post #5 of 8 (permalink) Old 03-21-2003, 04:49 PM
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The oil that's all over your engine compartment has attracted dirt, which has now plugged up the leaking gaskets and holes.

That's my answer, and I'm sticking with it!

'Electrical Guru: Let me Check Your Shorts! Ooops...that didn't turn out right.
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post #6 of 8 (permalink) Old 03-21-2003, 05:03 PM
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Here is what I have heard a couple times, and I can't really comment on it's accuracy because I don't know: If you are changing from normal to synthetic, the synthetic actually forces the remaining normal out (most of the time through the gaskets) and when it's all gone, it just stops leaking. Seems kinda weird to me, but like I say, that's what I heard.

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post #7 of 8 (permalink) Old 03-21-2003, 08:29 PM
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Have you driven the car to any evangelical revivals? Did someone lay on hands? Sounds like a miracle to me.

I couldn't repair your brakes, so I made your horn louder.

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post #8 of 8 (permalink) Old 03-21-2003, 10:37 PM
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gotta love "self healing cars" right? [IMG]/forums/images/icons/smile.gif[/IMG]


'65 Mustang w/ 302, 3 speed, and Granada disc brake conversion "The Crustang"
'71 Mustang Convertible w/ 351C, 3-speed "Rita"
also owned:
2000 F-150 "Oscar"
1997 Mark VIII LSC "Layla"
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