Conventional, Synthetic Blend, or Full Synthetic

[Manche757]

DirtyComa, aren't you ever going to have an opinion about anything?  Your comments made me curious about the metalurgy going on with zinc. I searched for the melting point of zinc. 787.2F. 419.5C. Since zinc is a primary metal and not an alloy those should be exact, probably at sea level. Next, I checked to see how hot it gets inside an engine, a less exact number. 600C, 1128.2F was the lowest I found. Others posted 1800-2500C or 3,272F-4,532F which must be wrong. Lets go with 600C. Steel melts at 1370C. 2500F. The melting point for iron is higher. Steel is an alloy with iron as it comes out of the ground as the primary element so the melting point may vary a little. With that temperature differnce from the melting point for zinc, melting could occur. Whether some plating of zinc to steel could occur, i can honestly state that I do not know.

[Manche757]

Divitha, that is some stunning mileage on your MJs. A lot of driving. You put most of that on them youself?

[dvitha]

All our vehicles are pickup and delivery vehicles. 3 times a week we get parts from Austin area, and from OKC. We pickup from all over Texas daily parts. 20 k a year is easy done and had seen 35k a year. We rotate the trucks so that we can keep them going.

 

[WyoCherokee]

Whatever is Cheapest on the shelf. 

 

[DirtyComanche]

6 hours ago, Manche757 said:

DirtyComa, aren't you ever going to have an opinion about anything?  Your comments made me curious about the metalurgy going on with zinc. I searched for the melting point of zinc. 787.2F. 419.5C. Since zinc is a primary metal and not an alloy those should be exact, probably at sea level. Next, I checked to see how hot it gets inside an engine, a less exact number. 600C, 1128.2F was the lowest I found. Others posted 1800-2500C or 3,272F-4,532F which must be wrong. Lets go with 600C. Steel melts at 1370C. 2500F. The melting point for iron is higher. Steel is an alloy with iron as it comes out of the ground as the primary element so the melting point may vary a little. With that temperature differnce from the melting point for zinc, melting could occur. Whether some plating of zinc to steel could occur, i can honestly state that I do not know.

 

The zinc isn't in elemental form.  It's not plating it because it's melting, it's a chemical reaction.

[coolwind57]

20 hours ago, 75sv1 said:

I pulled the link from MeanLemon's site.  The main reason Zinc is being phase out is the new emissions controls, or cats. It clogs them up. Not much of a problem on older vehicles. A bit harder to figure out how the new additives do in our engines.

Shopping for oil last night, I did see a diesel oil that actually mentions that it is not designed for gasoline engines with catalytic converters.  I think it was the Motorcraft brand.  

[75sv1]

https://www.bobistheoilguy.com/basic-lubrication-design/

Also, there are different certs for oils. I think CL-4 and CK-4 for diesel. I think CL-4 is the older cert. I would not try diesel oils in something newer. Probably 2000. Also, I would be hesitant on the last few years of the Cherokee with the Pre Cats. NO real direct info on this though. Metallurgy and roller cams might also influence the non use of ZPPD.

[WahooSteeler]

Interesting to note that while the factory manual has a footnote that says "10W-30 is preferred", it also says for temp ranges above 30*F 20w-40 or 20w-50 is suggested/approved. As expected, for temp ranges above 0*F 10w-30 or 10w-40 is recommended. 

[Manche757]

I thought we might have more MJ owners disclosing which type of oil they were using to get a bigger picture.  Conventional, synthetic or blend. Weight and general area you are in for temperature considerations.  If you haven't already and feel inclined, please post.  Just a short post is great.

 

I was surprised to find switching back and forth from conventional to synthetic and blends.   Question:  Am I correct in assuming no one is using any kind of engine  cleaner between these changes in types of oil for fear of causing seals to leak in old engines?  Or engine cleaner anytime.

[DirtyComanche]

33 minutes ago, Manche757 said:

I thought we might have more MJ owners disclosing which type of oil they were using to get a bigger picture.  Conventional, synthetic or blend. Weight and general area you are in for temperature considerations.  If you haven't already and feel inclined, please post.  Just a short post is great.

 

I was surprised to find switching back and forth from conventional to synthetic and blends.   Question:  Am I correct in assuming no one is using any kind of engine  cleaner between these changes in types of oil for fear of causing seals to leak in old engines?  Or engine cleaner anytime.

 

In case it wasn't clear, I live in a climate that varies from +40 degrees C to -45 degrees C and I use only synthetic.  I'm running Lucas right now because I get the best discount on it versus other oils with my account.  I will run any major brand synthetic though.  10w30 all year.

 

The "You can't switch oil types!!!!!!!11!!1!!!!one" thing is from oils of long ago, as in the 1980s.  I believe you will find almost all decent modern oils have very similar effects on seals and carbon buildup at this point in time.  Diesel oils are much higher in detergent agents though, and thus also have to run a lot more anti-foaming agents, but neither will adversely affect seals.  Seals are not kept sealing by buildup on them.  Engines you see that have massive sludge build up in them, and some "wise" person will say "Yup, that's what running Pennzoil will do to you" are actually the product of not changing the oil/filter often enough, it being contaminated by abnormal external factors (IE, running a K&N air filter will contaminate your oil considerably faster), contaminated by maintenance issues (very very small coolant leak into oil), the engine oil being subjected to prolonged temperatures outside of the range it was designed for (either by running it too cold, or too hot, for just too long), or using filters that are completely inadequate.

[Manche757]

Thanks Dirty.  Focus downstream from your comments.  If you bought an MJ, 30 years old and 175,000 miles or more on it and have no idea how well it was taken care of, you would not run any kind of engine cleaner through it?  Prior to coming to MJs, most car buyers are not buying 30 year old engines.

[Jeep Driver]

13 minutes ago, Manche757 said:

Thanks Dirty.  Focus downstream from your comments.  If you bought an MJ, 30 years old and 175,000 miles or more on it and have no idea how well it was taken care of, you would not run any kind of engine cleaner through it?  Prior to coming to MJs, most car buyers are not buying 30 year old engines.

Is this what you're getting at? Answer: No.

 

You want a clean engine? Build one and keep it clean. Otherwise, leave it alone. 

 

 

As for what oil in a 30  year old engine? It doesn't matter, this is an age old BS argument. 

 

New engine? it matters. 

[DirtyComanche]

3 hours ago, Manche757 said:

Thanks Dirty.  Focus downstream from your comments.  If you bought an MJ, 30 years old and 175,000 miles or more on it and have no idea how well it was taken care of, you would not run any kind of engine cleaner through it?  Prior to coming to MJs, most car buyers are not buying 30 year old engines.

 

I wouldn't try to clean it or throw mystery products in it.  It's clean enough.  So what if there's some sludge in the pan?  It's not hurting anything, use quality oil and change it regularly, you won't have a problem.

[75sv1]

      Mine would be if the lifters are clattering or clicking. Then I'd run Marvel Mystery Oil, Berryman's Chem B-12 or Seafoam.  Then again, a good diesel oil might do the trick. I have also tried a quart of trans fluid. I have tried the 5 minute Flush a long time ago. I would not use it, as it might be to aggressive, and cause bearing damage.

     As for the Pennzoil, Quaker State, Kendall and probably a few others, some of this info might be from the 80's. I heard stories where guys changed at 2K and their engines were clean. One guy posted some pictures on BITOG of an engine with over 200K using conventional oils. Looked clean, almost as clean as synthetics.  Basically, any brand name oil will be good. Just some better than others.

    Also, other factors can cause problems. When I lived in Tulsa, OK, I was in an Auto Parts store. A guy came in with an oil pan. It was filled with what looked like grease. I mean the whole sump. He said the rest of the engine was filled with it. Me and the counter guy just shrugged.  Looking back, either water or coolant was getting in there, or he might not have been running a thermostat.