Hey guys, from reading these forums i hear people have reported leaks developing after switching to synthetic. my 91 L03 has 30k on it, is it too late to go synthetic? thanks for your help guys.

 

Mine seemed to start leaking from the rear seal after switching to Mobil 1.

But it had about 200k when I switched. At 30k I would do what ever I wished.

DM

 

At this point it shouldn't be a problem...

In most cases the leaks develope because over the years (and miles) deposits starts forming inside your engine and when you switch to synthetic oil it acts as a detergent cleaning out all these deposits and when that happens the gaskets that have cracked or shrunk overtime are not sealing the oil in it's place therefore leaking...

I wouldn't recommend changing over to synthetic on any vehicle with an engine that has more than 70,000 miles on it...

 

I haven't had a problem putting synthetics in my cars (all with at least 100k miles on them ) for the past few years. I definitely wouldn't be worried about a 30k mile engine. Heck you have barely broken it in as far as I'm concerned!

 

Slightly off topic, but if you switch over to synthetic or a synthetic/regular blend, you cannot switch back to regular right?

 

you can do whatever you want as far as oil goes, the oil isn't the problem.

if your engine has 150k miles on it, you're gonna have some leaking issues in various areas of the engine. sythetic/mineral doesn't change that.

if you're having leaking issues and you don't have time or money to get those gaskets replaced, switch to a higher viscocity oil in the meantime.

i've run 0w-30, 5w-30, 10w-30, 30w, and 20w-50 in my engine. some mineral, some synthetic.

the only real difference there was between any of it was that the 0w-30(being thinner) leaked out in no time at all, i had to replace 4 quarts in 2 weeks. the straight 30w though(which i had to use as I suddenly had no oil pressure and all they had was w30), lasted me a long time, in fact it comparably "barely" had a leak after that.

the 20w-50 had similar results, but was just too thick for the engine, there was an obvious sluggishness to the engine, even when the oil was brand new.

usually these days I put a mix of 10w-30 and straight 30w in, it lasts longer, and i've still got a light enough weight to get into the nooks and crannies on start up.

all oil has detergents, many of them designed to be proprietary(as in, don't mix oil companies if you don't have to), that's not going to change based on synthetic or mineral. the main actual difference between synthetic and mineral is the point at which they become sludge, the point at which they oxidize, and in the case of mineral, what inherent minerals are actually in them.

don't blame synthetic oil for causing your engine to leak, the leaks were already there. the oil was simply doing it's job by removing your old sludge.

switching back and forth will make no difference, as the "damage" will have long since been done.

if you guys actually want some info on oil:

Bob Is The Oil Guy

 

My car has over 13xx,xxx miles and I switched to synthetic 30k ago NO LEAKS!!!!!

 

thanks alot guys really appreciate all the help.

 

You are welcome. I wished that I only had 30k on my engine. The only seals that are leaking on mine are the two original front and rear crankshaft units so you should be good to go. I agree with FreeLoader in that the syn basically should clean the varnish and gunk that may be preventing leaks before using a higher detergent oil.

You should also IMHO run some M1 ATF in the T5.