Two questions about oil

[dd74]

Can overfilling the oil reservoir result in oil leaks from the engine? My dipstick shows a little bit above maximum after I put a quart in a few days ago.

Does using synthetic oil help prevent oil leaks? I'm currently using 10w30.

Thanks.

[Nickshu]

Not sure on the overfilling, but aside from spilling over the breather tube I doubt it will cause more leakage from the engine.

I believe that synthetic oil will cause more leaks than dino oil b/c of its consistency being somewhat "thinner".

Nick.

[Emission]

Originally posted by dd74


Does using synthetic oil help prevent oil leaks? I'm currently using 10w30.

Thanks.

It does not prevent leaks.

It does not cause leaks.

The additional detergents in Synthetic oil will cause bad gaskets to leak when they previously did not as it helps break-down sludge (sludge build-up from dino oil can prevent bad gaskets from leaking).

[ChrisBennet]

Originally posted by Emission
It does not prevent leaks.

It does not cause leaks.

The additional detergents in Synthetic oil will cause bad gaskets to leak when they previously did not as it helps break-down sludge (sludge build-up from dino oil can prevent bad gaskets from leaking).

If you define "cause leaks" as making and engine leak after when it didn't before, yes, synthetic does cause leaks in older motors. Sythetic oil is also better at squeezing through smaller spaces. Mobil-1 will escape an unopened bottle for example.
-Chris
(Dino oil in the 911, synthetic in the winter car)

[gr8fl4porsche]

Seems like there is always a nice syn vs dino discussion every couple of weeks.

You are right Chris.

Mobil 1 does leak out of the container sealed from the factory.
Just bought 2 quarts yesterday at Walmart. Put the receipt in the bag. When I pulled the quarts out of the bag the receipt was covered in fresh oil. As I recall, the last time I bought Mobil 1, I had the same issue. Also just changed the oil in my Mountaineer,
I had 6 quarts of semi-synthetic in a bag for 3 months - not a drop in the bag.

My point is the same as Chris', if Mobil 1 can leak out of a closed plastic container, then it seems reasonable that it will find any weak point within your gaskets and seals.

BTW - switched over to Mobil 1 15W50 in my 87 with 84,000 miles and now I have oil hitting the garage floor and increased consumption. Also found increased consumption using the same oil in my Subaru GT.

[pwd72s]

Overfilling can cause an oil drip...at least on MFI cars...oil collects in the air filer housing, is routed out the low point of the housing to the ground, appearing like an "oil leak"...

[ed martin]

Huh, that's interesting. I have a '73 2.4 MFI and I have noticed oil leaking from the bottom of the air filter housing. I have been very careful not to overfill with oil. However iI did make the switch from dino to synthetic after reading much literature in regard to the pro's and cons.I will say this, without question, after doing so the engine produced way more leaks! In fact I believe as time progresses so do the leaks.I would imagine because the synthetics disolve varnish and sludge, the very thing occluding a potential leak.

[stealthn]

Originally posted by dd74
My dipstick shows a little bit above maximum after I put a quart in a few days ago.

Hi,

If you are saying your oil level is above the max on the dipstick, your oil is waaaaay overfilled. It should be in the middle between the max and min marks. You need to drain some out.

[dd74]

I've had the oil changed since beginning this thread, so all is fine.

Thanks.

[sweater914]

Which would folks rather have, varnished and sludge in the engine or nice clean shiny parts fully protected?

A few drops of oil on the floor = oil in the engine

Aircooled engines be it aviation or otherwise, tend to let oil past. Somewhere, somehow, the oil is always trying to get out.

A lousy 2 or 3 drops of oil can make the bottom of the engine look like the Exxon Valdez, the stuff smears and spreads all over the place.

[tryan]

there is a nice article in aprils vw trends. it compares flashpoint, pour point ect of dino and synthetic.

if a car is driven EVERY day, i use synthetic.

[RickM]

Quote:Mobil 1 does leak out of the container sealed from the factory.
Just bought 2 quarts yesterday at Walmart. Put the receipt in the bag. When I pulled the quarts out of the bag the receipt was covered in fresh oil. As I recall, the last time I bought Mobil 1, I had the same issue. Also just changed the oil in my Mountaineer,
I had 6 quarts of semi-synthetic in a bag for 3 months - not a drop in the bag.

I think it's a packaging issue. I get the stuff by the case from a friend who owns a Mobil station. The outside of the quart bottles are typically bone dry.

I've used Mobil 1 since it came on the market...and other synthetic brands previous....on many cars. I have never had a leak produced by using synthetic oil. Including high mile, older cars. IMO, it probably makes a small leak worse.

I have no affiliation with Mobil.

[RickM]

This is from the ExxonMobil site....

Again: I am not affiliated with Mobil or Exxon, nor am I out to promote them. I'm listing this info because I can easily admit that they know more about the subject than I.


Myth: Mobil 1 will leak out of the seals of older cars.

Reality: Mobil 1 does not cause leaks. In fact, new Mobil 1 with SuperSyn™ was tested in dozens of industry standard and OEM tests to prove its seal performance. It is fully compatible with the elastomeric materials from which all automotive seals and gaskets are made.

ExxonMobil engineers are wary of conventional oils that tout their use of additional seal-swelling agents. With extended use, these agents can over-soften engine seals, resulting in leaks. More to the point, an oil additive will not rejuvenate worn or damaged seals. The damaged seal may have been caused by a worn rotating metal component in the engine.

If an older engine is in good condition and does not have oil leaks, Mobil 1 with SuperSyn™ provides the same advantages as when used in a new engine. ExxonMobil recommends taking measures to repair the leaks, then using Mobil 1 with SuperSyn™. ExxonMobil also always recommends following the automobile manufacturer's manual for the proper oil to use.

Other "myths" listed:

-You should break in your engine with conventional oil, then switch to Mobil 1.

-You don't have to change the oil as often when using Mobil 1.

and others....