How many miles on a rebuilt 4.0 liter inline 6 before I can put full synthetic back i
#1
Newbie
Thread Starter
Join Date: Apr 2017
Posts: 3
Likes: 0
Received 0 Likes
on
0 Posts
Model: Cherokee
How many miles on a rebuilt 4.0 liter inline 6 before I can put full synthetic back i
I have a 2000 Jeep Grand Cherokee with a 4.0 liter inline 6 cylinder engine that has ran Mobil 1 full synthetic since the 1st oil change new. . It had 265,000 miles before we had a cracked head and broken piston. Engine has been rebuilt and we were told by the mechanic to not put synthetic back in until at least 60,000 miles. This makes no sense to me as we got 265,000 miles running full synthetic after the first oil change new.
Thoughts?
Thoughts?
#2
Newbie
Thread Starter
Join Date: Apr 2017
Posts: 3
Likes: 0
Received 0 Likes
on
0 Posts
Model: Cherokee
How many miles on a rebuilt 4.0 liter inline 6 before I can put full synthetic back i
I have a 2000 Jeep Grand Cherokee with a 4.0 liter inline 6 cylinder engine that has ran Mobil 1 full synthetic since the 1st oil change new. . It had 265,000 miles before we had a cracked head and broken piston. Engine has been rebuilt and we were told by the mechanic to not put synthetic back in until at least 60,000 miles. This makes no sense to me as we got 265,000 miles running full synthetic after the first oil change new.
Thoughts?
Thoughts?
Last edited by zatn02; 04-24-2017 at 08:58 PM.
#3
Member
Join Date: Feb 2016
Location: Tucson, AZ
Posts: 211
Likes: 0
Received 2 Likes
on
2 Posts
Year: 1999
Model: Cherokee
Engine: 4.0L
I have a 2000 Jeep Grand Cherokee with a 4.0 liter inline 6 cylinder engine that has ran Mobil 1 full synthetic since the 1st oil change new. . It had 265,000 miles before we had a cracked head and broken piston. Engine has been rebuilt and we were told by the mechanic to not put synthetic back in until at least 60,000 miles. This makes no sense to me as we got 265,000 miles running full synthetic after the first oil change new.
Thoughts?
Thoughts?
#4
CF Veteran
Join Date: May 2012
Location: Lost in the wilds of Virginia
Posts: 7,964
Received 952 Likes
on
767 Posts
Year: 1998 Classic (I'll get it running soon....) and 02 Grand
Model: Cherokee (XJ)
Engine: 4.0
FYI, the Grand Cherokee section is here. This part of the forum is for the regular Cherokee.
Find a new mechanic. Yours is an idiot.
That's because you have good sense!
That's because you have good sense!
#5
::CF Moderator::
Join Date: Aug 2011
Location: Prescott, Az
Posts: 43,867
Received 1,524 Likes
on
1,236 Posts
Year: 1990
Model: Cherokee (XJ)
Engine: 4.0
FYI, the Grand Cherokee section is here. This part of the forum is for the regular Cherokee.
Find a new mechanic. Yours is an idiot.
That's because you have good sense!
Find a new mechanic. Yours is an idiot.
That's because you have good sense!
Your mechanic is indeed an idiot. All sorts of new vehicles come from the factory with synthetic oil.
Trust your own intuition.
#6
Old fart with a wrench
Most synthetic oils today are not true synthetic, but ultra-refined petroleum oil. Ashland (Valvoline) runs it thru the cracking tower 4 times to purify it. It's still petroleum, not chemically built molecules. It's as stable as they can make it as far as breaking down under heat.
I used to use full synthetic in my 4.0 until it started using oil (as in burning it). Now I'm using conventional oil and cut my oil burning down considerably. I have ZERO, ZIP, NADA sludge in my engine because 3 times a week, it's running continuously for at least 3 hours while delivering newspapers.
Personally, I think synthetic oil is all hype for normal vehicles unless they are run at high temperatures with heavy loads all the time. In all the years I've been driving, I've never had an oil related engine failure using conventional oil. I DID have a fresh oil fill turn black in an air-cooled VW beetle on a trip from FL to NY though.
I used to use full synthetic in my 4.0 until it started using oil (as in burning it). Now I'm using conventional oil and cut my oil burning down considerably. I have ZERO, ZIP, NADA sludge in my engine because 3 times a week, it's running continuously for at least 3 hours while delivering newspapers.
Personally, I think synthetic oil is all hype for normal vehicles unless they are run at high temperatures with heavy loads all the time. In all the years I've been driving, I've never had an oil related engine failure using conventional oil. I DID have a fresh oil fill turn black in an air-cooled VW beetle on a trip from FL to NY though.
Last edited by dave1123; 04-25-2017 at 04:30 AM.
Thread
Thread Starter
Forum
Replies
Last Post
toddreg
Stock XJ Cherokee Tech. All XJ Non-modified/stock questions go here
0
04-23-2017 01:03 PM
el_dragon
Stock XJ Cherokee Tech. All XJ Non-modified/stock questions go here
13
04-20-2017 09:48 PM
xjmuddy
Stock XJ Cherokee Tech. All XJ Non-modified/stock questions go here
5
04-18-2017 10:58 PM
Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)