Switch from standard to synthetic at 165k?

BigClay

BigClay

Knower of useless ZJ things
Joined
Sep 24, 2008
Location
Winston-Salem
The 4.0 in my ZJ has 165k on it, and I want to try and get every possible mile out of it, so I am thinking of switching to synthetic. The jeep is not my DD and sits for periods of time (if that matters). So what do you think, is it a good idea to switch after these many miles?
 
I wouldn't, it will probably leak from every seal. Fill it with rotella 15-40 & go.
 
Jeff B said:
I wouldn't, it will probably leak from every seal. Fill it with rotella 15-40 & go.
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x3. If you go to 15-40 never go back to 10-30 or 10-40 tho. I had a truck with a 300 6 cyl in it that the po had used 15-40 diesel oil in, and i switched to 10-40 at 50k miles and it poured from every gasket.

Castrol or Valvoline High Mileage works great.
 
So I guess the concensus is to go to Rotella. Do I also need to switch from 10-30 to 15-40?
 
I would.
 
My wifes ZJ has over 200k on the 4.0. We use whatever 10w30 is cheapest at oil change time, and change every 5k miles. It has no leaks and runs better than most other 4.0's that I've driven (probably because I have it on a strict exercise routine).
 
I used 20-50 motor oil in most high mileage/oil leaking motors Ive had. when lucas came out I used it and found I could run 10-30 with one qt lucas with the same effect. I also had a car that I autocrossed for 3 years with over 150K miles on the motor. and when it started to give up, a few gaskets, tune up and a quart of lucas kept it alive for alooooot longer then I expected. revving 7 and 8 grand all the time. I gave it to my mom as a spare car and now a couple years later my uncle is driving it around King...I know he hasnt fixed it.....the darn thing wont die!
 
adam greene said:
i dont like it in a jeep or diesel
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Curious, why not in a diesel?

I've used the 15-40 flavor in my jeep and all the diesels at work (bobcat, backhoe, 4 snowcats with big merc diesels) and its been great in all of them.

And for whatever its worth, I'm at like 125k or so and have switched back and forth from 15-40 to 10-30 with no ill effects. YMMV.
 
My 96 zj has 290k on it ive been using synthetic since i got it and its runs great a little rocker knocking but that's all....
 
i dont understand why every one says it will leak its still 10w-30 or what ever they are the same thickness. they have to be the same consistabcy to be clasified 10w-30 or what ever oil you pic. a 10w-30 is a 10w-30 weather its regular or synthetic
 
thats just like people saying once you swithch you cant go back that a croc of crap they sell a synthetic blend wich is 1/2 reg oil and 1/2 syn so you can run synthetic for a while and swithch back to reg and so on if you choose
 
i just dont see how if its the exact same thikness, i just bought an OBS tahoe with 150K on it and will be swithcing to synthetic on the next oil change
 
Archdukeferdinand said:
Curious, why not in a diesel?
I've used the 15-40 flavor in my jeep and all the diesels at work (bobcat, backhoe, 4 snowcats with big merc diesels) and its been great in all of them.
And for whatever its worth, I'm at like 125k or so and have switched back and forth from 15-40 to 10-30 with no ill effects. YMMV.
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yea id like to know to?:confused:

theres a guy that runs around lexington with a 69 camaro 4 speed and a 502 BB and he runs rotella. and not in a diesel? just too many run it in a diesel. i run it in my 6.2 and everything else that takes oil never had any problems. plus for me its only a $4 and some jingle for an oil change. so that helps
 
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