Prep for synthetic

I am planing to switch from regular to synthetic engine oil in my 96'. It has 175K miles and the rear main leaks. If i install a new main seal, would that be enough to run synthetic? I hear synthetic will leak out of the seals if the engine has never used it? Any advise?

Synthetic doesn't have 'sludge" generation like regular oil, it also has detergents that will clean out sludge that is already there. If a leak is found after changing to synthetic, it's because the leak was already there and the detergents cleaned the sludge away that was stopping the leak from leaking. The main seal is the hardest seal to replace, so if you are doing that anyway, I wouldn't worry about it. Just switch and enjoy the extra HP and longer oil change duration

Cool Thanks!

I would also make sure from here on out you run a good quality oil filter. Try to stay with a Wix or Purolator quality as opposed to the cheaper house brands or Fram. When that synthetic starts doing it's work, a lot of the sludge will dissipate and it will either go into your filter or oil pump screen, you want the filter to catch as much as possible. Enjoy the changeover, I think you'll be happy with it.

I've changed vehicles with 130K miles with no ill effect as far as leakage or consumption.

If you want to switch, I would start with a Blend. Right now I am running Valvoline MaxLife Syn Blend and its good so far, actually it doesnt leak anymore (ha). For those that do not know, Napa Gold Filters are made by Wix (and are cheaper). But Bosch, Mobil1, and K&N oil filters are good. Right now I am running The Bosch filter, as I ran out of my supply of Napa Gold filters. And I get the Bosch filters with the oil change deal at Vatozone.

I'd be tempted to switch to synthetic just for the sludge cleaning abilities and hope it does leak so i would know where it's got a problem and get it fixed.

I'd change the front main while I was about it - the front and rear mains are the most likely seals to be "backed up" with collected crap, and to leak when cleaned. And, they're the biggest pain to replace.

Your 1996 should have the one-piece moulded rubber gasket OEM, but make sure that's what you get as a replacement. Saves you a lot of fighting putting it all back together... The moulded rubber gasket will fit engines all the way back to 1987 without incident.

Sounds good guys, thanks. How about oil stabilizer like Lucas or somthing? I heard it works pretty good.

-96JeepSpeed- said:

Sounds good guys, thanks. How about oil stabilizer like Lucas or somthing? I heard it works pretty good.

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I wouldn't think you'd need it with synthetic. Lucas is designed to improve the "stiction" of engine oil (making it carry up to parts better, stick to parts better, create a better film of oil,) while synthetic oils are designed to do that in the first place.

Save your money - switch to synthetic, think about a 15,000 mile change interval (that's what I've been running on my wife's car, but I switched it at 30K - before anything at all had a chance to build up, but long enough to make sure it was well worn in) and go for it.

Oh - be prepared, also, for valve guide seals to possibly leak on you. They can also build up sludge to help them - which gets stripped by the synthetic. You do not need to pull the head to replace them, if you're careful (shop air helps, but isn't strictly necessary either.)

I use Royal Purple synthetic and Bosch oil filters, never had an issue with it, changed over to synth at around 160k, the jeep is now at 220k