Gasket and leaking question

[Nevering]

I have a Jeep Wrangler 2003 X with about 60,000 miles. It has had conventional oil in it since the beginning.
I just purchased this used and thinking of putting a good synthetic in it, Mobil 1 , Motul, Redline, Amsoil, etc.

I called the Jeep dealer and asked about it and was told that if it had conventional from start and I switch to synthetic that I would surely get a leak at the RMS within a short amount of time. He also mentioned that if Jeep had started with synthetics from the start it would be OK.
I then called a shop that works on Jeep and he recommended Mobil 1 which he said was part conventional (I don't think so, but he could be using an additive)

I wanted to ask the professional here about going to a synthetic and problems with gaskets and leakage. I'm looking primarily for longer engine life.

thanks

 

[BRZED]

They fed you utter rubbish.

 

[CT8]

Maybe or maybe not but the question should be why change to syn oils?

 

[Ramblejam]

Those myths will never die. Unfortunately, these folks run on correlation proves causation, and it's difficult for them to acknowledge otherwise.

Originally Posted By: Nevering
I'm looking primarily for longer engine life.


We're talking about the 4.0L I6 here. In other words, it's just about the very last thing I'd worry about on a TJ Jeep.

P.S. - You don't need synthetics. Rotella 10w30 is inexpensive and widely available. $14.99/gallon at Advance Auto right now.

 

[Chris142]

Originally Posted By: Ramblejam
Those myths will never die. Unfortunately, these folks run on correlation proves causation, and it's difficult for them to acknowledge otherwise.

Originally Posted By: Nevering
I'm looking primarily for longer engine life.


We're talking about the 4.0L I6 here. In other words, it's just about the very last thing I'd worry about on a TJ Jeep.

His d35 rear axle will be the biggest problem.

 

[Nevering]

Changing to Synthetics ... I love them and have run them in my Audi's for years. I started with Amsoil and it changed a 120K mile engine that was about to go, or sounded like it to a purring kitten, and got another 120K on it, that was an 88 80 quattro. My newer Audi's have had Redline, Motul and Castrol Euro Syn. Loved them all, quiet engines, etc.

Like I said before I'm trying to get good engine life out of the new/used purchase and thinking a switch to a Syn would do the job. Just trying to get the best oil possible in the Jeep.

I also feel that everyone that I talk to will give me a different story. One of the reasons I came here. I've been on this site for awhile now and respect the oil knowledge that resides in this site.

I'm of the mind that a synthetic would make no difference on any of the gaskets, but when you have a Jeep parts guy tell you that you put a synthetic in after conventional you will have problems with the RMS in short order, kinda makes your ears perk up. But then I think about it ...

I do remember a thread a long time ago around here regard some type of Synthetic causing a drying of gaskets. I don't remember much about it but thought that someone here might. My guess is that if that problem ever existed, it's been resolved by now.

I appreciate all the feedback.

 

[Branson304]

The only reason a synthetic would "cause" any leaks is if the engine was varnished/sludged, & the synthetic oil cleaned out the sludge to reveal leaky oil seals.

Your Jeep only has 60,000 miles & is likely a clean engine. You could use synthetic if you wanted.

Mobil 1 is technically a mineral oil, the same as "conventionals" because it comes from a mineral base stock. Mobil 1 is a Group III+ oil, whereas conventionals are Group II. Mobil 1 & other "synthetics" have mineral base stocks but they are still significantly better oils than their conventional competition. Group III+ is widely accepted & marketed as synthetic as it should be.

 

[Nevering]

Originally Posted By: Ramblejam
Those myths will never die. Unfortunately, these folks run on correlation proves causation, and it's difficult for them to acknowledge otherwise.

Originally Posted By: Nevering
I'm looking primarily for longer engine life.


We're talking about the 4.0L I6 here. In other words, it's just about the very last thing I'd worry about on a TJ Jeep.

P.S. - You don't need synthetics. Rotella 10w30 is inexpensive and widely available. $14.99/gallon at Advance Auto right now.



Yes a 4.0L I6 . Why not put a Mobil 1 Syn in it ?

 

[Nevering]

Originally Posted By: BRZED
They fed you utter rubbish.


My thoughts also

 

[The_Jeff]

Gaskets aren't seals, BTW. Seals allow something rotating to pass through them, like the end of your crank.

Seals have to "weep" a tiny amount of oil to keep themselves lubricated.

Jeep 4.0 rear main seals do seem to leak if you look at them wrong, but syns aren't that much different as far as antagonizing seals.

 

[Nevering]

Originally Posted By: Chris142
Originally Posted By: Ramblejam
Those myths will never die. Unfortunately, these folks run on correlation proves causation, and it's difficult for them to acknowledge otherwise.

Originally Posted By: Nevering
I'm looking primarily for longer engine life.


We're talking about the 4.0L I6 here. In other words, it's just about the very last thing I'd worry about on a TJ Jeep.

His d35 rear axle will be the biggest problem.


I was told by both the Jeep dealer and the other place mentioned that Synthetics would be ok fro all the underneath stuff, diffs and all.

 

[Ramblejam]

How about this...

Can you reasonably articulate as to why utilizing synthetics (we're painting with a very broad brush here, as you've lumped Red Line/Motul/Mobil 1 all together) in your 4.0L engine would result in longer engine life?

 

[Nevering]

Originally Posted By: eljefino
Gaskets aren't seals, BTW. Seals allow something rotating to pass through them, like the end of your crank.

Seals have to "weep" a tiny amount of oil to keep themselves lubricated.

Jeep 4.0 rear main seals do seem to leak if you look at them wrong, but syns aren't that much different as far as antagonizing seals.


Thank you.

 

[Nevering]

Originally Posted By: Ramblejam
How about this...

Can you reasonably articulate as to why utilizing synthetics (we're painting with a very broad brush here, as you've lumped Red Line/Motul/Mobil 1 all together) in your 4.0L engine would result in longer engine life?



It's a gut feel that I have from past experience from my 88 Audi.

 

[Ramblejam]

I suspected that to be the answer.

Look, my point is this: Should you want to rack up the miles on this Jeep, then devote time to other aspects of the vehicle.

 

[Kuato]

I've changed used vehicles with up to 105k miles to synthetic, worst I got was a little wettish area near the rear seal, which dried within 3000 miles.

On another note: the 4.0 produces a lot more iron when M1 is used. Take what you want from that, but it's been well documented on several used oil analysis.

 

[bvance554]

Originally Posted By: Ramblejam
I suspected that to be the answer.

Look, my point is this: Should you want to rack up the miles on this Jeep, then devote time to other aspects of the vehicle.


Yes. I've never lost an engine because it decided that conventional oil just wasn't cutting it.

 

[Merkava_4]

Let's talk about something interesting for a change. Let's talking about how we're gonna pull the engine to change the rear main seal and all the cool tools we're gonna buy.