General question regarding synthetic and leaks

[DaveInLA]

My understanding is that switching from dino to synthetic doesn't cause leaks, but just makes them more pronounced.

That said, I recently switched my 1989 BMW 325is (127k miles) from Castrol GTX 20w-50 to M1 15w-50 EP. This was about 3 weeks/120 miles ago. No leaks or any other problems thus far. Does that mean I'm out of the woods, or might a leak develop later on? Thanks.

 

[coal68]

What I understand, If the engine is tight ( no current leaks) You should be fine, however if there are some leaks they may get worse as the synthetic cleans stuff up. if you make it through your next oil change you should be fine, from what I understand. Hot that helps.

 

[abimanyu]

I used to own 1998 C230, used Redline 10w30, leaked pretty bad around the head gasket but never high oil consumption.

 

[DaveInLA]

Geez, leaking with a 1998 car?! MB really isn't what it used to be...

Anyway, I'll wait a few months more before I decide if I'm in the clear. Thanks.

 

[JAG]

Redline motor and tranny oil leaked past seals in my then-new Subaru Impreza RS. Engine leaks were only internal...causing oil consumption to double compared to all other oils tried. Tranny oil leaked past output shafts seals and onto the ground!
I'd only be concerned if you were using a mostly ester based oil, like Redline.

 

[ShotGun429]

Fiqure this one out: I started putting Mobil 1 15W-50 (back in 1989) in my mid 1950's Farm tractor (Ferguson 35 HP)that leaked a little bit on the floor,since then has not dripped at all!! The things got leather/and rope seals in it.Runs Great also!!

 

[glennc]

JAG it is interesting that you had problems with Redline tranny oil. I've always used it and never had a leak.

Dave, FWIW I have the same car, minus the "s," but almost double the mileage (I put on 30-40k a year). I used M1 for a while, 15W-50, and had some oil consumption. Switched to dino and it pretty much went away. The M1 was also noisy in the top end. Wish I had UOAs but I don't.

- Glenn

 

[Islandvic]

In my '95 GMC Z-71 with 168k miles and my '96 Crown Vic w/ 145k miles, after switching to Synthetic form years of clock work like dino oil changes, no leaks occured.

The Vic now consumes LESS oil.

My '00 Silverado was switched to M1 this year, but the truck only has 25k miles, so the engine is just now broken in.

 

[JohnBrowning]

If anything Redlines high POE content should swell the seals not shrink them. PAO based lubes are almost bulit proof in terms of seal issue. I have never ever seen Redline cause any leaks in any vechile that was well maintained and had good seals. Rember ester's are added to PAO to keep it from shrinking the seals.