Leaks after switching from dino to synthetic - Harley Davidson Forums: Harley Davidson Motorcycle Forum
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post #1 of 17 (permalink) Old 12-26-2012, 05:58 PM Thread Starter
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Leaks after switching from dino to synthetic

I've been looking through the forum and searching but haven't found a clear answer. I've heard of folks developing leaks after the switch and the opposite saying those problems have been worked out. Just wanted one more check before I do so. I have a new to me 04 Electra Glide with 28,000 on her, I ride every day and while it's cold now it will be hot here in the South before we know it and I like the aspects of the synthetic. Has anyone had any problems with the switch?
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post #2 of 17 (permalink) Old 12-26-2012, 07:04 PM
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I swapped to SYN3 at the 1K service on my 2012 FLTRX.

No problems yet but I'd think if a leak developed it wouldn't be due to the synthetic oil, most likely the gasket was going to leak anyway.

Last edited by secoleman57; 12-26-2012 at 08:54 PM.
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post #3 of 17 (permalink) Old 12-26-2012, 07:41 PM
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No issues here on either 08 Heritage or 2012 Switchback when I switched to SYN3 in the both Oil and Primary cases. Went with Red Line in the Transmission and no issues there either.

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post #4 of 17 (permalink) Old 12-26-2012, 07:51 PM
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The instances of motors developing leaks after switching to a synthetic oil are pretty old, not the problem now as when synthetics first came out.

What happened was on motors that had many miles (way more than 28,000), were run on older dino oil that didn't have the detergents that modern oils do. This allowed sludge to build up, and this sludge is what was actually keeping the motor from leaking. Then when they switched to synthetic oil with a better detergent package, it cleaned out the sludge and thus showed evidence of bad rocker box gaskets that the sludge was masking.

Even today's dino oil has a better detergent additive package than the dino oils used when synthetic oils first came to market.

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post #5 of 17 (permalink) Old 12-26-2012, 07:56 PM
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I'd stay away from royal purple if your concerned about developing oil leaks . Ask me how I know !
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post #6 of 17 (permalink) Old 12-26-2012, 08:00 PM
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Kainam's explanation is the only story I could swallow. Otherwise, I'd say leaks occurring when changing fluids is either coincidence or nonsense.

A sludgy, high-miler impacted by detergents sounds reasonable, though.

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post #7 of 17 (permalink) Old 12-27-2012, 08:00 AM
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I had the exact same concern as you...and a bad experience with a low mileage Explorer..leaked like a sieve after the change.. but that was in 1993. When I bought this bike in Feb it had 7,000 miles on it, not very well cared for. I changed oil and filter and ran it another grand on dino (to clean it out). I then switched to Amsoil. That was 5,000 miles ago. No leaks, I'd do it again in a heart beat, I like the protection in the heat. Just my .02

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post #8 of 17 (permalink) Old 12-27-2012, 08:05 AM
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Not to worry, so long as U use HD's Syn3...

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post #9 of 17 (permalink) Old 12-27-2012, 08:22 AM
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No problems with the change.
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post #10 of 17 (permalink) Old 12-27-2012, 09:08 AM
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As stated: The oil isn't what caused the leak, rather sludge and a weak seal.

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