Synthetic oil

[Melgottaexcoupe]

Would doin an oil change and replacing oil with synthetic mess ne thing up...sorry i knw noobie question

[Melgottaexcoupe]

Also wut type of oil is best for h23engine wit 140,000 miles

[Leung]

The only thing i would be worried about switching to a synthetic oil that late into an engine's life is that sometimes the extra detergents in the oil will remove deposits that keep oil from leaking.

Now if the engine was fully rebuilt with all new seals, then i'd definitely use a fully synthetic oil because you can go longer in between oil change periods and it'll keep sludge from forming.

Honestly if i were you, i would just stick with a conventional oil like Castrol or Valvoline. From a past experience with my Ford Ranger, which had 160K miles, when i used Valvoline high mileage oil it developed an oil leak. I went back to the regular valvoline oil in a white bottle and it still leaked but not as bad.

[DirtyBird33]

I have heard that you can't mix the two oils together. But if you drain the oil it should be fine.

[AbsurdNY]

I have heard that you can't mix the two oils together. But if you drain the oil it should be fine.

It has nothing to do with "mixing the two oils". It's all about the condition the seals are in. Synthetic oils are thin so if the seals do not provide a really good seal, they will leak. If you use nothing but synthetic oil from the start it is better because the oil is lighter and keeps the engine from gunking up so you dont have to change the oil as often and lighter oil puts less strain on the engine in theory, but old engines have oil seals. Conventional oil could be gunked up so much it is actually stopping a problem from happening. Synthetic oil is just gonna eat away at that gunk and make stuff leak

[DirtyBird33]

Ok his what I I found on Google. But I'm no expert or do I know if it cause it to. My opinion would to not use it if its not broken don't fix.
Myth #5 - Synthetic oil causes engine leaks. Synthetic motor oils eat gasket material and cause engines to leak. Synthetic motor oils affect engine seals and result in excessive oil leakage. Synthetic oil can’t be used on high-mileage engines. Synthetic and synthetic blend motor oils cannot be used in older or high-mileage vehicles. Fact: Synthetic oils do not cause engine oil leaks. Deteriorated and hardened seals and gasket material cause engine oil leaks. If the seals are already leaking with conventional motor oil, they will leak with synthetic oil. If the seals are in good condition, synthetic oils may be used in high-mileage engines.

[AbsurdNY]

Ok his what I I found on Google. But I'm no expert or do I know if it cause it to. My opinion would to not use it if its not broken don't fix.
Myth #5 - Synthetic oil causes engine leaks. Synthetic motor oils eat gasket material and cause engines to leak. Synthetic motor oils affect engine seals and result in excessive oil leakage. Synthetic oil can’t be used on high-mileage engines. Synthetic and synthetic blend motor oils cannot be used in older or high-mileage vehicles. Fact: Synthetic oils do not cause engine oil leaks. Deteriorated and hardened seals and gasket material cause engine oil leaks. If the seals are already leaking with conventional motor oil, they will leak with synthetic oil. If the seals are in good condition, synthetic oils may be used in high-mileage engines.

That myth does not explain the true reason synthetic oils are not good in old engines though. Synthetic oils don't eat gaskets. They dissolve oil buildup. If the buildup is around the seal and the seal is already bad, the buildup would stop the oil from leaking. No one is saying "synthetic oil causes engine leaks" but they can make the leak that is already there worse. You might not even know the seals in your engine are bad right now but they could be.

[deevergote]

Synthetic engine oils provide more protection... so honestly, they are better. Mixing oils doesn't hurt a thing (you can even buy a "synthetic blend"... that's what my H22 uses.) If your seals are worn and the synthetic oil leaks, REPLACE YOUR SEALS!

[9tAkord]

Deev is right change for the better oil and deal with the leaks if it happens...

[youngflyndsaved]

I just experienced somethin like this happen to me recently after i changed out my motor. Ran it for awhile, my engine wasn't leaking any oil at all. Then i did an oil change with Mobil1 Full Synthetic (don't know what oil was used previously) and my crankshaft seal began to leak..

[Flyingsheep]

I just replaced the crankshaft seals (on both front and back), intermediate shaft seal, cam seal, dipstick o-ring, spark plug tube seals, valve cover gasket, and oil pan gasket. Would it be safe to use synthetic now? I think the only thing left is the head gasket and I don't want to touch it. Plus there doesn't appear to be any leak coming out of it.

[nusdogg]

Whatever synthetic you're going with, make sure it's not Mobile1 5w30.

I heard those now adays are like water which can do damages. They ain't what they are back in the day. Now I'm running Amsoil 10w30, maybe expensive, but will save your engine in the long run.

[Flyingsheep]

Any enlightenment on my question?

[Slow]

I have switched to synthetic in several higher mileage vehicles I have owned, and increased leaking has never been an issue.

For oil we have gone to castrol syntec 0w-30, after doing research on bob's the oil guy site, and we have been happy with it.

[Fleetw00d]

I've also started using Castrol Syntec 5W30 in several of my high mileage vehicles without trouble.