Synthetic oil

jeepmedic46 · **Posted:** Mon Apr 06, 2009 8:00 pm

Have over 106,000 miles on my Kj and would like to switch to synthetic oil. Is it to late to do that?

jeepkj02 · **Posted:** Mon Apr 06, 2009 8:09 pm

I wouldn't recommend it. Switching to synthetic that late in the game, your engine could start to leak. Just continue using the oil you are currently running.

jeepmedic46 · **Posted:** Mon Apr 06, 2009 8:13 pm

Thank you, I wanted to make sure before I did. Where I have so many miles should I treat the engine with anything to get gunk out?

jeepkj02 · **Posted:** Mon Apr 06, 2009 8:37 pm

Try pouring some seafoam through the brake booster vaccum line. That will clean intake. Pour seafoam in your oil will clean the gunk off your valves and the rest of your valvetrain. You can also pour some in your tank that will clean your fuel system, fuel injectors, etc...

You will need about 2 cans. 1 can for your tank (full tank), 1/2 can in your oil and the other half in your vacuum line/throttle body.

jeepmedic46 · **Posted:** Mon Apr 06, 2009 9:02 pm

I will try that, Thank you

JJsTJ · **Posted:** Mon Apr 06, 2009 10:21 pm

Shouldn't be a problem if your seals are in ok shape which they are on most modern engines. I converted my 94 Cherokee 4.0L over to Amsoil at 150K miles and it now has close to 190K and No leaks! I only replaced the rear main (and pan in the process) which was leaking when I bought it and all other seals are tight. Valve cover (notorious for leaking), oil filter housing, etc are all leak free.

I wouldn't hesitate to convert on a newer modern engine. Now an old, originally sealed engine in a classic.....I might worry about those.....but then I would Want to reseal it anyway so what the hey!

edit:
BTW, the additives in good quality synthetics are known to condition seals so if anything, it might even help prevent leaks.

Oh and I would like an explanation on how syn could cause a leak.

JeepinJarhead03 · **Posted:** Mon Apr 06, 2009 10:24 pm

i've been wary of switchin

ps, your new avatar is hypnotic

JJsTJ · **Posted:** Mon Apr 06, 2009 10:25 pm

JeepinJarhead03 wrote:

i've been wary of switchin

ps, your new avatar is hypnotic

wary why? splain.

JeepinJarhead03 · **Posted:** Mon Apr 06, 2009 10:26 pm

just don't want it springin leaks

stuck in the old ways i guess :lol:

JJsTJ · **Posted:** Mon Apr 06, 2009 10:32 pm

JeepinJarhead03 wrote:

just don't want it springin leaks

stuck in the old ways i guess :lol:

Shouldn't if your current seals are holding ok.

Funny thing is reading stuff like: "don't use it, it will clean everything up so much that the built up gunk that is sealing your engine will go away and then your seals will leak"......and then read something along the lines of: " use some of this or that engine cleaner in the oil to clean everything up" ummm.....hello?

Not saying anyone said those exact words, just that is the kind of stuff I have read in the past.
I have run syns in Numerous vehicles over the years of all types, mileages, old and new and only leaks I had were ones that existed before converting over and I have even seen seals leak less over time when running synthetics, including semi-syns.

JeepinJarhead03 · **Posted:** Mon Apr 06, 2009 10:39 pm

i usually don't run engine cleaners either, i also change oil more frequently than suggested

i did almost get semi syn last time i changed my oil, and then my hand drifted to what i usually use

i guess im just chicken

DryBones · **Posted:** Mon Apr 06, 2009 10:45 pm

switched the wifes 02 KJ to Mobil1 at around 75K. 2 changes since and now at88k on the 3rd change since going away form dino I just went to Amsoil in it. I'm not afraid. Also switching the 05 to Amsoil from Mobil1 on the next change. Been running Mobil1 since around 45K and now I am at 90k.

JJsTJ · **Posted:** Mon Apr 06, 2009 10:47 pm

JeepinJarhead03 wrote:

i usually don't run engine cleaners either, i also change oil more frequently than suggested

i did almost get semi syn last time i changed my oil, and then my hand drifted to what i usually use

i guess im just chicken

eh its all good! as long as the ol gal keeps tickin' right!?

tommudd · **Posted:** Mon Apr 06, 2009 10:55 pm

I have switched some over with 150,000 before and never had a problem. Older 60/70 model engines then may be a problem but 90s/2000s should not be unless you already have a problem

JeepinJarhead03 · **Posted:** Mon Apr 06, 2009 11:01 pm

i don't have any problems :lol:

and yes as long as she keeps on tickin, or.. Not tickin

I've gotta change the oil again in month or two, maybe i'll unchicken myself and order a few cases before then

jeepmedic46 · **Posted:** Tue Apr 07, 2009 7:47 am

No problems with the motor. Maybe I'll give it a try.

jeepkj02 · **Posted:** Tue Apr 07, 2009 8:59 am

When I switched over to synthetic (around 60k), I ran two/three rounds (3k OCI) of a semi-synthetic/synthetic blend, then went to the full synthetic.

long_tall_texan · **Posted:** Tue Apr 07, 2009 11:41 am

FWIW, I switched an 87 Caprice Classic with 100k+ miles over to Full synthetic and never had a leak one out of it. I did seafoam twice thru to oil first to get all of the gunk out to begin with. It had never been regularly maintained before I got it. But after the seafoam and synthetic , it ran great for many more miles. Still going as far as I know.

DryBones · **Posted:** Tue Apr 07, 2009 11:52 am

can or should you run Seafoam with synthetic oil or is this real overkill? May have to try a can through a tank of gas just for grins.

tommudd · **Posted:** Tue Apr 07, 2009 12:08 pm

DryBones wrote:

can or should you run Seafoam with synthetic oil or is this real overkill? May have to try a can through a tank of gas just for grins.

It states on the can you can run it with synthetic oil so guess so ??? I have never seen the benefit of doing so but ? Guess you could, I feel the oil has everything needed in it already if it is a high grade oil.

Synthetic oil

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