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Syntheitc Oil Safe?

TERRor

NAXJA Forum User
Location
San Antonio, Tx
A couple of weeks ago I bought a 1997 XJ w/ 4.0 & AW4 with 256K on the odometer. 98% of it was highway miles. Is it safe to run Synthetic or Synthetic blend oil?
 
Any noticable leaks? If so they may or may not leak more. What I recommend to people with higher mileage engines that are thinking about switching, is to run a syn. blend first. Then if it is to your liking, then go full syn.
Vatozone has good oil change deals with all types of oil. But for full syn I recommend Amsoil. You can run full syn in your diffs, trans, and t-case as well
 
this is a myth. If you got cork...probably not a smart idea. rubber gaskets will not even sneeze at synthetic. If you have an oil leak...you got a leak (different oil isn't going to make a difference) I think people just start looking after they started using synthetic.

just my .02
1996 XJ 204k
synthetic since I bought it at 185k 3 years ago
 
Another thing I read the other day at work in a lube manual. It said that synthetics are not compatable with RTV.

That may be the problems people have running synthetic.
 
All depends on the condition of your seals. I bought my XJ with 62K on it, and switched straight over to Full Synthetic at 70K. Immediately had leaks. Addressed the valve cover gasket and oil filter adapter o-rings first. The oil pan gasket and rear main had started seeping, so I waited until it got worse. Fast forward to last month, at 130K, the oil pan gasket and rear main finally got to the point where it was becoming an issue. Replaced them, and immediately started losing oil again from the oil filter adapter o-rings. I replaced them once again, this morning actually. I've been considering switching to a Synthetic Blend, but I will wait to see how it does now. I did top it off with half a quart of Valvoline Synthetic Blend this morning however.
 
just read this from amsoil.
Is it true that installing AMSOIL or other synthetic oils will cause my engine to leak oil?
Answer: In modern vehicles, there is no risk of AMSOIL motor oil leaking. In fact, AMSOIL motor oil is fully compatible with modern seal materials. It is properly formulated to condition seals, keeping them pliable to prevent leakage.

so with that being said... uncc i think you just had a gremlin and it happened at the same time.

i have a 2000 XJ with 120K miles and i run royal purple full synthetic 10w-40 with a royal purple filter no leaks or problems at all. it actually quieted down what i think is lifter knock

i say going to synthetic is fine as long as you dont mind spending 60 dollars an oil change =/
 
just read this from amsoil.
Is it true that installing AMSOIL or other synthetic oils will cause my engine to leak oil?
Answer: In modern vehicles, there is no risk of AMSOIL motor oil leaking. In fact, AMSOIL motor oil is fully compatible with modern seal materials. It is properly formulated to condition seals, keeping them pliable to prevent leakage.

so with that being said... uncc i think you just had a gremlin and it happened at the same time.

i have a 2000 XJ with 120K miles and i run royal purple full synthetic 10w-40 with a royal purple filter no leaks or problems at all. it actually quieted down what i think is lifter knock

i say going to synthetic is fine as long as you dont mind spending 60 dollars an oil change =/

While it may be compatible with modern seal materials, I still believe that the condition of your seals prior to switching has all to do it if it's going to leak. If your seals are worn out and there is some sludge build up that's preventing your seals from leaking with conventional oil being used, then absolutely switching to synthetic will cause leaks. This is because the synthetic properties break down the sludge build up inside the motor.

I agree, synthetic definitely makes for a quieter running motor, especially on those cold morning. However I had to read several documents for work when I was going through training on the differences between conventional, synthetic blend, and pure synthetic motor oils.

I'm not saying your wrong, i'm just saying that switching to synthetic from conventional on a higher mileage motor, especially one that's had a hard life (lots of short distance driving where it didn't get warmed up much thus forming sludge) is discouraged. To each their own however.
 
=) 60 dollars is my price. 7.99 a quart i think for my royal purple times that by 6 quarts, then the price of a royal purple filter... your at about 60 dollars bud.
 
While it may be compatible with modern seal materials, I still believe that the condition of your seals prior to switching has all to do it if it's going to leak. If your seals are worn out and there is some sludge build up that's preventing your seals from leaking with conventional oil being used, then absolutely switching to synthetic will cause leaks. This is because the synthetic properties break down the sludge build up inside the motor.

x2. Mine had over 150k when I got it and small leaks. Engine is dirty but rarely saw a drop. I started blending in synthetic and when I got to mostly synthetic it started leaking worse. I've gone back to regular and it's slowed down some. Synthetic has 2 things against it when it comes to leaks: it cleans up gunk and it's thinner than regular. So it clears out the natural "stop leak" and it'll flow quicker than regular dyno juice. I like the synthetic but on this leaky motor I'll just change the oil more often. How much better is it to run synthetic for 10k vs. regular for 5k, anyways?

If I get a new motor I'll run synthetic.
 
x2. Mine had over 150k when I got it and small leaks. Engine is dirty but rarely saw a drop. I started blending in synthetic and when I got to mostly synthetic it started leaking worse. I've gone back to regular and it's slowed down some. Synthetic has 2 things against it when it comes to leaks: it cleans up gunk and it's thinner than regular. So it clears out the natural "stop leak" and it'll flow quicker than regular dyno juice. I like the synthetic but on this leaky motor I'll just change the oil more often. How much better is it to run synthetic for 10k vs. regular for 5k, anyways?

If I get a new motor I'll run synthetic.

I'm in the same situation as you right now. I've taken care of all my seals, but i'm still leaking just a little bit. We've got Valvoline going on sale next month at work, so I'm going to pick up some synthetic blend and give that a shot to see what happens.

On my mom's Jeep however, since she bought it new and I switched it over to Mobil 1 at 20K, she's still leak free and comin up on 90K.
 
I run mobil-1 oil and filters in all 4 jeeps, the 97ZJ, both 97TJ's and the 98XJ, all have over 150,000 miles on them, changed the ZJ over when we got it two years ago at 90 something or so. One 97TJ now has 198,000mi on it's 4 banger, does loose around a quart between changes but no obvious leaks that I have noticed. Oh, they are all synthetic from the engine, tranny, transfercase and both diffs.
 
Where are you getting WIX filters for $3.50? I pay around $8.00 for mine,but I also use the 51515 (longer filter,same for FORD).
Sorry, you are correct. I ordered mine from rockauto and it WAS just over $8. I was used to running Frams or Wallyworld cheapos, but recently changed after reading more info on NAXJA forum. :doh:
 
Napa Gold oil filters are the same as Wix. Bosch is good too (most of what comes with the vatozone oil special.)
 
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