switching to synthetic

[2637042]

I have a 96 jeep grand cherokee with about 100000 miles on it and was thinking about switching to synthetic oil. the engine is the 4.0 by the way. i was thinking this oil might be better because i started towing quite often and in high temps. any thoughts on doing this?<br /><br />by the way, the engine burns no oil at this time and leaks none either using penzoil 10w30.

 

[LubeDude]

Re: switching to synthetic

There souldnt be a problem as long as your vehicle has had proper maintenance over the miles. In you climate, I would think you could use a 10W-30 Mobil 1, or Pennz, or whatever. Ive read that the 4 liter Jeeps like 40 weight, but generally that is if you are using a little oil to start with, I am personally using Amsoil now of course and using a 5W-30 in my Ranger that tows an 18' (glass) Bass Tracker, unsure of the weight. I changed it over to synthetic at 140,000, no problems, the first synthetic I used was Mobil1 10W-30. I like the Amsoil as it tends to thicken a little as it gets older and more miles, it starts out as a heavey 30 weight and ends up a light 40. I just changed it out at 8,500 Miles. Unless you are using oil now, I would not reccomend anything heavier. Im learning that the old addage of using a heavier oil just because you have more miles isnt necesarily true, as in thicker is better. Its not proving to be true as most thought, including myself. Use a good filter such as the Pure 1 from Purolator, the Mobil1 filter is good , but way over priced.

 

[ZmOz]

Re: switching to synthetic

Get ready for leaks! If the rear main and other gaskets haven't been replaced, they usually start leaking at around 100k in that engine if you don't change your oil. You are almost guaranteed to leak if it's had dino all it's life and those things haven't been changed.

 

[LubeDude]

Re: switching to synthetic

OZ, you have hung around at the BITOG forums long enough to know that isnt true. I know you know your Jeep 4 liters, but the esters in the synthetics will actually soften the seals over a little time and can actually stop some leaks, No leaks in my Ranger, and like I said, I changed it over at 140,000.<br /><br />I did reread your post and you did say, "if you do not change your oil", and that is true. Im under the usumpsion that he has maintained his.

 

[ZmOz]

Re: switching to synthetic

Synthetic cleans the seals...and opens holes that were covered by sludge. The 4.0 is an EXTREMELY leaky motor when you don't do anything drastic like switching oil at that high of mileage. I can almost guarantee it will start leaking if it has the original seals and gaskets. It would be leaking soon anyway if you didn't change oils. Changing to synthetic will just aggrivate this.

 

[LubeDude]

Re: switching to synthetic

OZ, I know you know these engine well and will not argue the point with you because of this and value your opinion, what you say is intirly possible, I would still do it, but the final decision of course is up to ratherBfishin.<br /><br />If he doesnt want to go with synthetic because of what you are saying , I would reccomend the Dello 400 15W-40 because of all the posts Ive read about the 4 liters liking a 40 weight, also because it is very easy to get. but with a synthetic I still would stay with a 30.

 

[SoulWinner]

Re: switching to synthetic

I would like to comment on the statement that thicker is not always better. I sometimes do some machine work in my shop. Working on this old Ford Lawn Tractor I have done some fab and machine work and I have noticed that thinner lubricants(like ZEP or Marvelous Mystery Oil) work great to cool drill bits and stuff, but heavey stuff (like gear or motor oil) will actually stop bits from cutting. Is this because the heavier lubricants are slipperier?

 

[LubeDude]

Re: switching to synthetic

What you are saying is true, but we are talking about different things when it comes to motor oils and using them as they are intended. I think what you are experiencing is due to the anti qaully additives like ZDDP which do not allow metal to metal contact. I follow a forum where there are a lot of oil analysis reports posted. Granted, the arguments usually are over very minute amounts of wear, but even a minute amount of wear in 3000 miles will show itsself as a lot of wear in 100,000 miles. I used to be in the crowd that used 20W-50 in everything, thinking that heavy ment less wear, but with the actual results that have been posted over the months that I have followed the forums, the lighter weight oils in the same vehicle with the same use show consistantly less wear than a heavier oil. The only place that the heavy oils out perform the lighter weights are in very hot environments and constant heavy hauling. But this isnt the average use in most cars and trucks. And then, only an increase from say a 30 to a 40 is needed. honestly, 20W-50 has vurtually no place in todays engines. Say for the last ten years. Even if the owners manual says its ok to use, its proving out that they arent doing the customer any good. Are they destroying the engines, No, but it is taking mileage away in terms of fuel mileage and life of the engine. I myself have gone from using a 15W-40 in my pick-up back to a 5W-30 synthetic. Another interesting thing is the new 0W-20 reccomendations on some of the new cars. When I first saw this I thought to myself, "Not in any of my cars", But surprisingly enough, the wear #s are coming in very good, so I guess its time for a change in thinking. But only use these oils in engines designed to run them. Going to a 5W-30 isnt doing yourself a favor.

 

[2637042]

Re: switching to synthetic

i have alraedy replaced my rear main seal, but nothing else. i have considered using 15w30 delo before but the weight seems a bit to high. but this engine's design is something like 30 years old, so it may like a heavy oil. <br /><br />hey Lubedude, whats so great about this delo oil, i have seen that you really like it, expecially on inboard boat engines.

 

[LubeDude]

Re: switching to synthetic

The Chevron Dello oils are a hydrocracked petroium oil base stock. Very similar to the Base stock of the Castrol Syntec. Its as close to a synthetic that you can get with out paying the price. It also, (being a Diesel oil ) has very high acid fighting abilities and very high detergency. Also a high TBN of around 12, and a very good dose of Zink. (a friction aditive) Nearly stops metal to metal contact. All in all, it is just a very robust oil. Easily will go 5,000 miles between changes, and available at a reasonable price. There is a 15W-30 weight available also, but a little harder to find normally. In your climate it would be fine year around. If you deside to use it, make your first change at 2,500 or so as it will really clean your engine the first time, and will continue to do so.

 

[DJ]

Re: switching to synthetic

Come on guys, how many times do we have to hash this out. <br /><br />If someone wants to go syn., let them.<br /><br />I have opinions too, but I've found it's better, for my sanity, to keep most of them to myself- here.<br /><br />Opinions are RARELY changed by facts.

 

[LubeDude]

Re: switching to synthetic

If you do not want to read it, then why are you here. He has asked a question, and we are just trying to answer it. Seems simple enough to me.

 

[DJ]

Re: switching to synthetic

Lubedude.<br /><br />Sorry I butted in. I'll stay out of any of your conversations.

 

[k5ranger]

Re: switching to synthetic

thanks for the question....i myself was just telling my not-so-fishing-crazy other half that we should start running synth. in our vehicles. i have a 93 jgc laredo with 190k miles on her 4.0 liter. if i don't run straight 30 weihgt she will smoke like a teenager on a friday night.

 

[LubeDude]

Re: switching to synthetic

Come on now DJ, You know you are welcome. I thought you were compaining about the posting and figured if you didnt like it, then why were you there. Thats all..Like others have told me, Dont take it so personal.

 

[LubeDude]

Re: switching to synthetic

K5ranger: I think its too late to make the switch now.

 

[Skinnywater]

Re: switching to synthetic

ratherbfishin,<br />It won't hurt a thing to try using a synthetic. <br /><br />Things to look out for is a higher consumption of the oil. Switch back if it's an issue. <br /><br />Then take note of additional or an increased seepage or leakage.<br />Synthetic won't cause seals to leak, but will slip past moderately worn gaskets or seals. <br />Don't expect the synthetic to eventually cure already worn parts. Replace the leaking seals or gaskets instead.<br /><br />The 40w is a bad idea, unless your entering that puppy in the Paris/Dakar this year. Then I'd only recommend it if you promised to change back after the race. <br />Stay close to the viscosity recommended by mopar.

 

[LubeDude]

Re: switching to synthetic

Skinnywaters reply is pretty much right on, If you are not using oil now, I would very much doubt you would use any with synthetic unless leakage is a problem. Synthetics have higher flash points and the ring seal it going to be better, so if you are using just a little, you actually may see a slightly less amount of usage.<br /><br />When I just changed my Ranger at 8,500 miles with the Mobil1, it was about an eighth of an inch from the full mark and that is for the full 8,500 miles. It used about a half quart with the 15W-40 Dello I was using before at 3,000.<br />In your climate you could easily use the 15W-40 Dello, but I dont think you need to or should, unless you were towng heavily all the time.

 

[2637042]

Re: switching to synthetic

thanks for all the info guys. i think ill try mobil1 and see what happens. i also like the dello 10w-30, but it seems a bit hard to find at any local stores. they all carry 15w-40 though. i let you all know what happens

 

[SpinnerBait_Nut]

Re: switching to synthetic

How about the Rotella oil, is it any count?