start using synthetics?

[Jay Welch]

Much as I like the stuff.....I probably wouldn't do it.

Jay in MA

 

[XgeekstarX]

So at almost 202K its not worth going over to Mobil One unless im ready to repair alot of seals?

not unless you love oil stains in your driveway, an oily back window, and the lovely smell of burning oil on your exhaust pipe.

 

[Devilfrog]

yeah, the problem isn't the synthetic oils ... it's the condition of the seals. The synth oils will clean better and flow better ... and so they find all the chinks in the armour so to speak. Switching back to dino will eventually slow things down again since they don't flow as well and will begin the build up process again, and plug up some of the smaller cracks and pinholes. Realisticly the seals and such should be replaced and then run what you want.
me I just use a synth blend in everything (it offers better cleaning and lubricity with less issues in older engines) ... and when my junk starts to leak I break out the tools, or I'd go nuts worrying about a severe engine failure on the way to work (when you drive four hours out into the middle of hippyville, BC theres alot of road with no help for miles (148kms between the last two towns on the route) these thing sometimes tend to cross your mind))

 

[Jay Welch]

http://www.boss302.com/oil.htm

You might want to read the section that talks to Synthetic Blends. On page 11 it states that the most synthetic base present in any of the blends is 5%. I'll stick with my blend of 50/50 (or better) or whatever is harmonious in my 2000 XJ.

Jay in MA

 

[Devilfrog]

Interesting read .... think I'll still do the blend thing, but I'll just do it myself (one quart synth for every three dino sounds about right to me).
call me crazy, most do

 

[majic_tech]

i dont think so... but my personal experience with changing to synthetics on a well used engine have givven me mixed feelings on doing it again... i changed a ford 2.5L with over 100K on it over to mobil 1 and it ran AWESOME.. increase in mileage, ran smoother and quieter.. sounds like a commercial but it was that noticable.. but conversely i had a new 99 TJ with a 2.5L and at 7500 miles i went with Castrol synthetic and the rear main started pissing within only a few days. back to petroleum and it stopped.. went to Mobil1 and it started again...
i like synthetics and run them in everything but tranys and engines right now... my next new engine will be broken in with royal purple....

Ummmmm I could be wrong but I think synthetics inhibit the break in process...

 

[Ben H]

switched to synthetic in my 2000 with 60k leaked out the oil filter housing and fixed it with new o rings and good old fashioned oil.

 

[majic_tech]

Interesting read .... think I'll still do the blend thing, but I'll just do it myself (one quart synth for every three dino sounds about right to me).
call me crazy, most do

I do this in trannys that call for 80/90 when its really cold helps stiff shifting big time also i do it in the transfercases that use atf I use 1 qt mobile 1 and the rest 80/90.I sold dads old chevy 3/4 ton just last year with 275000 miles on her and we kept the transfer case that way since it had 30000 on it (junk np208) never had a problem or a rebuild. He wasnt hard on it but I sure as hell was...........shhhh.....

 

[haynesn12]

actually it is true that a motor cannot be broken in with synthetic if the person did not use the right hone on the cylinders. i worked at a performance engine shop and we had to ask the people before hand what type of oil they were going to run so we could use the right hones. if the right hone is used then synthetic can be used from the start. so it can go either way.

 

[majic_tech]

why hasnt anyone given the true scientific explaination behind all these leak posts? ...ok I will......The synthetics have a smaller molecular structure so they leak easier.....just as if you do a r134 conversion on an r12 ac system without replacing the hoses with what they call barrier hose. They will leak the refrigerant out. Kinda like trying to hold water in a gunny sack as opposed to a bucket.

 

[Vertisce]

why hasnt anyone given the true scientific explaination behind all these leak posts? ...ok I will......The synthetics have a smaller molecular structure so they leak easier.....just as if you do a r134 conversion on an r12 ac system without replacing the hoses with what they call barrier hose. They will leak the refrigerant out. Kinda like trying to hold water in a gunny sack as opposed to a bucket.

I explained sometime long ago about the molecular size difference between synthetic and regular oil.

Edit---My bad...that post was on Jeepforum...

 

[majic_tech]

In this thread you did? guess i didnt see it ........through all the ranting about leaks ....by all means guys use synthetics and fix your leaks your just prolonging the inevitable

 

[Vertisce]

When it comes right down to it its not just the leaks in your seals thats the problem. If you switch to synthetics and your Jeep has 150K miles on it your also running the risk of losing a lot of oil pressure. The piston chambers will also get cleaned out by the synthetics along with the pistons themselves and if there are any grooves or scratches on the piston or in the chamber your gonna be in a world of trouble.

 

[Jay Welch]

No offense to anybody but I think the subject of dried out seals and synthetics cleaning out all of the sludge etc being the cause of the leaking in these engines is largely overestimated.

I just read a post on this forum regarding someone changing out the rear main seal on a 4.0. The thread had a pic. I didn't realize the seal in a 4.0 is a 2 piece seal. My guess is that the problem with synthetics is largely the 2 piece design and the fact that the molecular makeup of synthetic oil allows the oil to flow freely through this 2 piece seal,whether it's between the 2 gaps in the seal(s) or around the circumference of the crank.

I just checked the Advance page. Every car I have ever converted over to synthetics at high mileage uses a 1 piece design....never leaked a drop.

Jay in MA
2000 XJ

 

[Vertisce]

My old Dakota had a one peice seal and when I converted to synthetics several seals started to leak in several places. Then when I tore down the engine I found out that many scratches and cracks within my piston chamber were cleaned out and I was losing a lot of pressure.

 

[Jay Welch]

.........when I tore down the engine I found out that many scratches and cracks within my piston chamber were cleaned out and I was losing a lot of pressure.

Just curious Vertisce. How do you know that the Synthetic is what cleaned out those "scratches and cracks"?

 

[Vertisce]

There simply was nothing else it could have been and it happened about 2 weeks after I did the oil change. Never used any additives or cleaners or anything...simply had to be the synthetic oil.

 

[Jay Welch]

Was the engine really tired or was it running great and you just wanted to put the good stuff in to keep it running that way?

 

[Vertisce]

It was actually running just fine before...I just thought I would switch to synthetics to make it last longer...that was at 120k miles. Unfortunately with that engine it was just a mistake.

 

[Jay Welch]

Whose oil did you use?

Did you tear it down to fix the leaks or was it running poorly also after the addition of synthetic?