Opinions on switching a high mileage vehicle to synthetic oil

[white trash wagon]

Seeking opinions on switching a high mileage vehicle to synthetic oil. 160K miles, all oil changes done like clockwork every 3000 miles- so little to no sludge.

My only experience with synthetic oils was 15 years ago. I started a then new car with Mobil 1, by 60K miles it had an oil leak. I switched to dino oil & the leak went away in 2 days & never came back.

But since monitored fleet usage of synthetic oils has documented improved fuel economy - it's tempting.

[black2002ls]

Seeking opinions on switching a high mileage vehicle to synthetic oil. 160K miles, all oil changes done like clockwork every 3000 miles- so little to no sludge.

My only experience with synthetic oils was 15 years ago. I started a then new car with Mobil 1, by 60K miles it had an oil leak. I switched to dino oil & the leak went away in 2 days & never came back.

But since monitored fleet usage of synthetic oils has documented improved fuel economy - it's tempting.

I have used mobile 1 in my truck since I bought it with 40k miles. It now has 195k. It has developed an oil leak over the last couple of years. I have wondered in switching to dino oil will slow/stop the leak. Not sure if it will hurt mpg's, or the motor if I switch at this point

[2011GT]

Synthetic oils do not cause oil leaks. Modern day syn oils are great. Check out bobistheoilguy.com great info there. I use cheap ass walmart brand synthetic oil in my cars. No problems. I also used black stone lab to do a test on my oil. After 10k miles on my oil they said it still had about 30% of it's life left. Even with that info I still change my oil every 6k miles. 3k miles is fucking retarded unless you're running olive oil lol.

[Gasser64]

I have done it and never had a problem. No leaks

[line-em-up]

In the past, I've had issues where my motor would leak oil with synthetic, but if I switched back to regular oil, it would stop.

I only use synthetic oil. It's worth it to me because I tend to go +10k miles between changes. I have never had an issue with a motor wearing out, even after 300k miles.

[Captain Crawfish]

I switched mine when I bought it at 100k. No problems 130k now

[Tannerm]

Bought my 99 5.0 explorer with 130k miles. Was using Mobil 1 5w30 when I bought it. 3 years later and at 160k, no leaks or problems. Still use the same Mobil 1. In my mustangs and trucks i used motorcraft. Bobtheoilguy talks highly of motorcraft. Just a thought if u wanna use a semi synthetic. My bmw used mobil 1 0w40. Synthetic ftw.

[mikeb]

I have a 1999 Jeep Cherokee sport that I bought used with 147k miles. I switched to synthetic on the first oil change I did and have been running it ever since. It leaked oil when I bought it and it still leaks today at 196k miles LOL...... I have run a good synth like mobil1 but now i'm broke so it gets a steady diet of el-cheapo walmart super tech synth. No issues whatsoever.

[Pokulski-Blatz]

I have a 1999 Jeep Cherokee sport that I bought used with 147k miles. I switched to synthetic on the first oil change I did and have been running it ever since. It leaked oil when I bought it and it still leaks today at 196k miles LOL...... I have run a good synth like mobil1 but now i'm broke so it gets a steady diet of el-cheapo walmart super tech synth. No issues whatsoever.

Just fix the oil leak, they only leak from 3 places really. All are pretty easy to fix.

[mikeb]

Just fix the oil leak, they only leak from 3 places really. All are pretty easy to fix.

It's the rear main seal and the head gasket seems to be weeping a bit too. I live in an apartment right now with no place to do that kind of work and no spare car to drive if I run into problems. So it's just gonna have to leak for now.


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[Pokulski-Blatz]

It's the rear main seal and the head gasket seems to be weeping a bit too. I live in an apartment right now with no place to do that kind of work and no spare car to drive if I run into problems. So it's just gonna have to leak for now.


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Both are super easy. You can change the rear main in the Jeep.

Rear main.

http://www.go.jeep-xj.info/HowtoRearMain.htm

Sure it isnt the valve cover gasket? That is more common. I have only seen one head gasket leak oil on a 4.0.

[mikeb]

I was hoping it was the valve cover gasket so I changed it awhile ago but the leak is still there. I think that someone has been into this engine before and maybe that's a part of it leaking.


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