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Mobil 1...worth it???

K2XJ

NAXJA Forum User
Location
British Columbia
Ok...one last oil question...

I was at the store this afternoon looking at all the different oils and was think of putting mobil1 in my 95 xj...but it is 3x the price of conventional oil. Is it going to be worth the price to switch or not??
THX
 
If it's under 60000 miles or so, I'd say go for it. Most people say they get leaks with synthetic if they have high mileage already. When I bought my 2000 Sport w/ 55k miles, I switched it to synth. I go 10000 miles between changes. It seems to keep everything I can see inside the valve cover clean. I've got about 120,000 on it now and all is well, except a small leak at the rear of the valve cover.

I first started using synthetic on a new 88 Mustang GT after the first oil change at 3000mi. I ran that car hard (autocrossing, etc.) to 225,000 miles and the engine and drivetrain were all that was good when I got rid of it. I ran synth lubes throughout and never had to replace anything engine, tranny, rearend related, not even the wheel bearings. I ran 10,000 mi oil changes and the other lubes were only changed once to go to synth. Never had oil leaks from anywhere.

Every decent car/Jeep I've had since has gotten the same treatment on the engine oil, wheel bearings, etc. I mainly do it now because I don't want to change the oil in both vehicles every 4-5 weeks... we drive alot.
 
I use it. It still gets changed every 3K miles along with the filter.
I know it protects better, so that's worth the extra cost to me.
 
At over 255,000mi on my 98 I use it and have since about 6,000mi when it it was new. I change it regularly at 5,000mi or thereabouts. All our jeeps and the wifes olds use it, 10w30 in the jeeps and 5w30 in the olds.
 
I have used it since I bought mine with 36K on it. Got 88K now. I change every 5500 miles.
 
If it's a high milage jeep then don't use it. If it's fairly new then go ahead. I've heard about them cleaning too well and revealing worn internals. Sometimes on an older engine a nice buildup of crud is what's holding it together.

On my new Xterra I started using synthetic after the break in point.
 
Which oil you use is for some reason something people are willing to go to war over, don't understand it. I know the US Army uses Mil-L-7808 and Mil-L-23699 in their turboshaft engines. Both oils are synthetic.

Knowing the thousands of gallons of oil used annually by the Military the cost accountants would have them go to a "cheaper" oil if the performance benefits of synthetics were worth less than the additional cost of the oil.

The Military changes the oil when it tests bad, not sooner. They take oil samples like every 5, 10, or 25 hours dependent on what the engineers had decided. They monitor the stuff in the oil and can lead to early removal of the engine due to a failing bearing, etc.

We as owner's of vehicles do not test our oil, we just change it when our change out interval is accumilated on the oil.

There are superior features of synthetic which pay benefits under severe operating conditions. I use synthetic in both of my vehicles - 88 XJ Pioneer and a 2003 Buick Le Sabre. I switched the XJ at 133,000 miles but before I did I had changed the oil pan, valve cover and oil filter mount gaskets so most of the seals were new.

I would recommend changing the oil at the interval in your owner's manual, use severe or normal schedule depending on how you operate the vehicle. If you are doing oil samples then you can extend the oil service life until it is fully "dirty".

With that said, it up to you what oil you use - normal or synthetic. The reason we change oil it to remove the bad stuff from engine wear so it does not cause accelerated wear.

One last thing, people over look the Oil Filter but it is just as important. If the filter goes into bypass then you get no filtering. Back in the early 80s when the talked about Mobil 1 being 25,000 mile oil the thing not mentioned was the life of an oil filter. The Engineer who talked to my Society of Automotive Engineers (SAE) chapture in college on this issue said to expect 10,000 miles out of a filter. If you run your oil longer it was recommended to change the filter every 10K miles even if you kept the synthetic in for 25K miles.
 
Hi :wave:

As still written, synthetic has the advantage, that it lasts longer than normal. The "only problem" with synthetic is that it washes out the oil-mud in older engines. this oil-mud is mostly at the seals (where it can help to seal too) and in corners (there ypu don't want it) and it's a mixture of all the dirt in the engine (dust, metal, ..). So when synthetic oil washes out the mud maybe the seals are not proof any more. :wave:

greetings from Austria
Rainer
 
Go back and look at Valvoline VR1 Racing Oil ...

It's like the difference between lubing your innards with Chivas Regal or Chivas Royal Salute.

Don't ask why I used that analogy ...

K2XJ said:
Ok...one last oil question...

I was at the store this afternoon looking at all the different oils and was think of putting mobil1 in my 95 xj...but it is 3x the price of conventional oil. Is it going to be worth the price to switch or not??
THX
 
Last edited:
I think its worth it just for the simple point that it has a higher "burning point,boiling point", then conventional oils which is quite handy when the engine heats up from the slow speeds of trail riding.
It want break down like conv. oils do
 
jeepbme said:
I think its worth it just for the simple point that it has a higher "burning point,boiling point", then conventional oils which is quite handy when the engine heats up from the slow speeds of trail riding.
It want break down like conv. oils do

Or simply the fact that the XJ 4.0 is one of the hotter-running engines on the planet!! I switched my XJ to Mobil1 last fall at 54k.

I used to run conventional oil, and changed it (with filter) every 3k.

I now run the synthetic oil, change it at 6k, but do a "mid-term" filter change at 3k anyway.

Old math:
6 x 1.79 = 10.74 + 2.99 filter = $13.73 every 3k miles. $27.46 for 6k.

New math:
$19.94 + 4.59 (5+1 qt Mobil1 at Walmart) + 2 x 2.99 = $30.51 for 6k.

So the cost is almost identical... and I feel the Mobil1 is a far better oil.

I was never a believer in synthetics when the cost differential was $0.99 vs $5.00. But now that the cost differential is $1.79 vs $4.00, the math works differently!

Den
 
I switched to synthetic and they overfilled me (yes I was lazy and let someone else do it) now about 2weeks later, my gas mileage is no more. I was gettin 15 city now I see 9-13. I don't think its the oil, so we're doing an alignment tomorrow. If it still doesn't change I'll look into other stuff. Would overfilling by a half-quart cause problems like that? I drained some but apparantly not enough.
 
I started Mobil1 when I got my 93XJ at 178K. Have put over 20k on it, no leaks at all. Hopefully things are cleaner on the inside. My oil pressure stays pretty steady about 45 as well.

"XJ's are like snowflakes...no two are alike!"
 
I have used Mobil One in the 88 cheif since day of purchase (@120k). Three years and 20k later, no complaints. Great lube. I also run it in the y2kxj with no complaints, I change it with filter every 5k.
 
Ok...i think im convinced to be switching to synth...my xj has bout 75k miles on it..is this going to cause problems??...most people seem to switch at a lower mileage.

One other note...how many quarts will i need to fill my rig ('95)

THX
 
4.0L 6qts

Shouldnt hurt anything, only help. Even with higher mileage, it will pretty much cease future wear on parts if changed when necessary.
 
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